Primary Breast Cancer Patients Research Articles

Racial and survival disparities in inflammatory breast cancer (IBC) and non-IBC: a population-based study focused on Native Hawaiians and other Pacific Islanders

BackgroundIt is well known that race is an independent predictor of breast cancer mortality and advanced stage at diagnosis. Inflammatory breast cancer (IBC) is the most aggressive type of breast cancer and has distinct clinical and biological features. Previous studies have shown that Blacks have a higher incidence of IBC than Whites. However, the proportion of IBC and the role of race on prognosis in Native Hawaiian and other Pacific Islander (NH/PI) populations with breast cancer are poorly understood. In this study, we aimed to examine the proportion of IBC to non-IBC in NH/PIs and to identify the clinicopathological, biological, and socioeconomic factors associated with the overall survival of NH/PIs compared to other races.MethodsUtilizing a comprehensive cancer registry from the largest hospital in Hawaii, newly diagnosed primary invasive breast cancer patients diagnosed between 2000 and 2018 were identified. Univariate and multivariate Cox proportional hazards models were used to test the association between race and clinical outcomes. Variables with P-values <0.05 in the univariate analysis and race (variable of interest) were included in a multivariate analysis.ResultsThe cohort included 3691 patients, 60 of whom had IBC. NH/PI race had the highest proportion of IBC compared to other races (3.44%) but was not found to be an independent poor prognostic factor in IBC (HR 1.17 [95%CI 0.26-5.22]). Conversely, NH/PI race was associated with worse survival outcomes in patients with non-IBC (HR 1.65 [95%CI, 1.14-2.39]) along with other factors such as lack of insurance, underinsured status, triple-negative breast cancer (TNBC) subtype, age, and advanced clinical stage.ConclusionsThe findings of this study highlight that NH/PIs had higher rates of IBC and inferior survival in non-IBC compared to other races but not in IBC. It is essential to disaggregate NH/PI race from Asians in future population-based research studies. Further research is needed to understand the factors contributing to higher rates of IBC and poor survival outcomes in NH/PIs with non-IBC as well as targeted interventions to improve breast cancer outcomes in this population to ultimately help improve survival rates and reduce health inequities in NH/PIs with breast cancer.

Abstract PO2-24-02: Molecular characterization of primary tumors associated with various CTCs’ subpopulation

Abstract Background: Circulating tumor cells (CTCs) are prognostic in primary breast cancer (BC) patients and represent a heterogeneous population of cells with different phenotypes and biological value. However, molecular characterization of primary tumors associated with various CTCs’ subpopulation is lacking. This study aimed to identify expression of genes associated with the presence of different CTCs subpopulations in primary BC patients using a comprehensive genomics approach. Methods: This prospective ongoing study included 312 patients (pts) with non-metastatic BC enrolled from March 2012 to February 2015. CTCs were detected on day -1 to 0 before surgery. Isolated peripheral blood mononuclear cells (PBMC) were depleted of hematopoietic cells using RossetteSepTM kit negative selection with anti-CD45 antibody. RNA extracted from CD45-depleted (CD45-) PBMC was interrogated for expression of EMT-inducing transcription factors (TWIST1, SNAIL1, SLUG, ZEB1) and epithelial (CK19) gene transcripts by quantitative reverse transcription-PCR. Expressions of gene transcripts in CD45- PBMC of patients were compared to those of CD45- PBMC of 60 healthy donors. Formalin-fixed paraffin-embedded tumor tissue was subject for gene expression analysis performed by HTG EdgeSeq Oncology Biomarker panel (HTG Molecular Diagnostics, Inc., Tucson, USA). Results: CTCs with epithelial phenotype (CTC_EP) were detected in 30 (9.6%) pts, CTC with EMT (epithelial-to-mesenchymal transition) were detected in 54 (17.3%), while blood of 79 (25.3%) pts exhibit at least one type of CTC. Patients with detectable CTC in peripheral blood had inferior disease-free survival compared to patients without detectable CTC (HR = 0.62, 95% CI 0.37-1.06, P=0.048). There was no association between epithelial CTCs and analysed patients/tumour variables. Genes expression analysis identified 7 differentially expressed genes in patients with the CTC_EP phenotype (CHGA, MESP1, COL2A1, MT2A, COMP, MMP7 and ORM2), 200 genes associated with CTC_EMT phenotype (top 10 genes included CHGA, CECR6, SMAD2, HUS1, FGF10, HNF1A, SEC61G, CDK4, CD44 and F3). Analysis identified that low expression of CHGA and MMP7 was consistently associated with any CTC subpopulations. Conclusions: In this study for the first-time revealed gene expressions associated with various CTC subpopulations. We suppose that these genes could represent potential therapeutic target aimed to inhibit metastatic cascade in breast cancer. Citation Format: Michal Mego, Gabriel Minarik, Milan Hucko, Katarina Kalavska, Marian Karaba, Juraj Benca, Tatiana Sedlackova, Lucia Kucerova, Jozef Mardiak, Lubos Klucar, Zuzana Cierna. Molecular characterization of primary tumors associated with various CTCs’ subpopulation [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-24-02.

Abstract PO4-11-03: Impact of Short Term Fasting (STF) on Fatigue developing in primary breast cancer (BC) patients receiving the Henderson or Sparano Scheme in the prospective multicentre FIT2- cohort

Abstract Background: Experimentally, it has been shown that short-term fasting (STF) induces a “protective mode” in healthy cells against chemotherapeutic toxicity while it enhances the susceptibility of tumor cells to chemotherapy. In healthy cells, fasting triggers distinct protective metabolic and gene expression changes, such as upregulation of DNA repair mechanisms, autophagy, and downshift of metabolic pathways including IGF-1-dependent signaling. This study was conducted to assess feasibility, quality of life (QoL) including chemotherapy-induced fatigue (CTF) comparing STF around each chemotherapy (4xAC or 4xEC) to a plant-based low-sugar diet (PBD). Methods: Newly diagnosed BC-patients treated by the Henderson or Sparano scheme were included in this randomised, controlled, multicenter study. CTF was assessed by the FACIT-F questionnaire before (day 0) and after chemotherapy (day 7) as well as at months 4 (V1) and 6 (V2). Results: Of the included n=106 patients, 52 were randomized to STF and 54 to PBD. n=90 (84.9%) patients obtained AC/EC+Pac and 16 (15.1%) AC/EC+Doc. FACIT-F showed no significant difference at baseline (STF 42.8; PBD 41.3; p=0.708). The differences between the corresponding FACIT-F Trial Outcome Index resp. Total FACIT-F at cycle 4 day 7 were 13.1 (SE 4.7) resp. 15.8 (SE 5.6), both in favor of STF (statistically significant (p < 0.007) and clinically relevant (minimal important difference (MID) > 5). This difference was visible for all breast cancer subtypes, i.e. luminal A & B, as well as HER2 overexpressed and triple negative tumors, with the STF group showing no clinically relevant fatigue after 4 cycles of chemotherapy (FACIT-F > 34), across all subtypes. The opposite was true for the PBD group (FACIT-F < 34) across all subtypes. FACIT-F (22.7) for PBD in HER2 overexpressed and triple negative tumors was significantly worse than those in luminal A and B patients (FACIT-F= 29.1; difference 6.4 > MID=3). STF was well tolerated and there were no serious adverse effects. Conclusion: STF during chemotherapy is well tolerated and appears to improve QoL including fatigue during chemotherapy compared to a plant-based low-sugar diet, independent of intrinsic subtypes. Citation Format: Daniela Koppold, Christian Kessler, Manfred Wischnewsky, Ixquic Alvarado, Nico Steckhan, Cornelia Kempter, Marion Paul, Barbara Brückner, Dorothea Fischer, Aysen Wunschel, Rainer Stange, Etienne Hanslian, Michael Jeitler, Andreas Michalsen. Impact of Short Term Fasting (STF) on Fatigue developing in primary breast cancer (BC) patients receiving the Henderson or Sparano Scheme in the prospective multicentre FIT2- cohort [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-11-03.

Abstract PO2-07-05: Deep learning model for automated quantification of HER2 expression in invasive breast cancers from immunohistochemical whole slide images

Abstract Introduction Human epidermal growth factor receptor 2 (HER2) protein overexpression and/or HER2 gene amplification is found in about 20% of invasive breast cancers. Considering the results of the DESTINY-Breast trials confirming the remarkable efficacy of anti-HER2 antibody drug-conjugate (T-Dxd) in both HER2-overexpressed and HER2-low tumors, it is necessary to identify not only HER2 (immunohistochemistry (IHC) score 3+) overexpressing tumors, but also HER2-low tumors. The latter category, defined as IHC1+ or IHC2+ but non-amplified, has proven to be challenging even for experienced pathologists, with high inter-observer variability. Here, we validate the performance of a deep learning (DL) model at: 1) predicting the IHC score from IHC histological features and 2) identifying HER2-low tumors with high sensitivity. Methods 675 HER2 stained IHC slides from primary breast cancer patients were selected based on pathology reports across three different cohorts (KCL_GSTT_1 n=369; Cypath_Breast n=214; KCL_GSTT_2 n=92). The slides were digitized and reviewed by expert breast pathologists. Specifically, Cypath_Breast and KCL_GSTT_2 were each annotated by one expert pathologist, while KCL_GSTT_1 was annotated by 5 expert pathologists with the ground truth defined as a majority vote between the 5 annotators. Cypath_Breast was assigned as the “discovery” set; while KCL_GSTT_1 and KCL_GSTT_2 were used as two independent validation cohorts. The model was specifically trained to extract features from IHC tiles to ensure they would capture both the staining intensity and the staining location on the cells (membrane, cytoplasmic or nuclei). The one-vs-one (OVO) and one-vs-rest (OVR) AUC as well as sensitivity and specificity to HER2-low and positive tumors were used as metrics to assess the performance of our model. An expert pathologist reviewed the most predictive regions of HER2 expression. Results After review by expert pathologists, 59 slides from KCL_GSTT_1 were removed either because of folded tissue, blurriness or because there was too little tissue. The IHC scores (0/1+/2+/3+) for the 3 cohorts were distributed as follows; Cypath_Breast: 42/120/36/16; KCL_GSTT_1: 120/90/52/48; KCL_GSTT_2: 54/22/15/1. For KCL_GSTT_1, the average agreement between the 5 expert pathologists amounted to a Cohen’s Kappa score of 0.63. Following training on Cypath_Breast, the performance of the model are presented in An ablation study proved that a feature extractor trained on IHC tiles outperformed an in-house extractor solely trained on H&E tiles (OVO AUC 0.95 vs 0.93 on KCL_GSTT_1; DeLong p< 0.001). Specifically, the model performed best at distinguishing HER2-negative (HER2 IHC 0) from HER2-low and HER2-positive tumors with a sensitivity (0 vs 1+/2+/3+) of 0.95 [0.93 - 0.98] and a specificity (0 vs 1+/2+/3+) of 0.78 [0.72 - 0.84] on KCL_GSTT_1. We observed the same tendency on KCL_GSTT_2 with a sensitivity (0 vs 1+/2+/3+) of 0.97 [0.91 - 1.00] and a specificity of 0.91 [0.83 - 0.98]. More importantly, the DL model reached a Cohen’s Kappa score of 0.72 [0.67 - 0.77] with the ground truth on KCL_GSTT_1, surpassing the average agreement Kappa score between expert pathologists (0.63). The most predictive regions showed cytoplasmic staining in tumor regions. Conclusion Our model provides a path towards a fully automated workflow for identifying up to 95% of breast cancer patients who could potentially benefit from anti-HER2 targeted therapies. Additionally, we show the utility of AI-based tools to minimize discrepancies among pathologists and assist in the diagnostic patient pathway. Table 1: Results of external validation on KCL_GSTT_1 and KCL_GSTT_2 <grpahic> Cohorts OVO AUC OVR AUC IHC 0 OVR AUC IHC 1+ OVR AUC IHC 2+ OVR AUC IHC 3+ KCL_GSTT_1 0.95 0.95 0.80 0.91 0.99 [0.93 - 0.96] [0.94 - 0.95] [0.79 - 0.82] [0.90 - 0.92] [0.99 - 1.00] KCL_GSTT_2 0.92 0.97 0.78 0.84 N/A [0.90 - 0.93] [0.96 - 0.98] [0.76 - 0.81] [0.80 - 0.88] Citation Format: Pierre-Antoine Bannier, Loïc Herpin, Rémy Dubois, Lydwine Van Praet, Charles Maussion, Ellen Amonoo, Anca Mera, Jasmine Timbres, Cheryl Gillett, Elinor Sawyer, Patrycja Gazinska, Piotr Ziolkowski, Roberto Salgado, Sheeba Irshad. Deep learning model for automated quantification of HER2 expression in invasive breast cancers from immunohistochemical whole slide images [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-07-05.

Abstract PO1-24-03: The clinicopathological and prognostic significance of HER2-low breast cancer: A comparative analysis between HER2-low and HER2-zero subtypes

Abstract Background: HER2-low breast cancer (BC) is a newly defined subset of HER2-negative BC that has a HER2 immunohistochemical (IHC)-1+ or 2+/ISH negative phenotype. Recent clinical trials have demonstrated the clinical benefits of novel HER2 directing ADCs in treating this group. It is uncertain whether HER2-low BC represents a distinct biological/clinical subgroup or if the HER2-low categorization has any prognostic significance. We retrospectively investigated the clinicopathological and prognostic significance of HER2-low BC and compared it with HER2-0 BC. Methods: Primary BC patients who underwent surgery from January 2000 to March 2023 were enrolled in this retrospective study. A total of 10,215 invasive BC cases with Stage I-III were analyzed. The HER2 status was divided into 3 groups: HER2-0, HER2-low, and HER2-positive (3+ or 2+ with positive ISH). The clinicopathological factors investigated were age, nodal status, tumor size, nuclear grade (NG), ER/PgR (cutoff points; 1% and 10%), and the Ki-67 index value (cutoff points: 15% and 30%). The pCR rate in patients who underwent neoadjuvant chemotherapy (NAC) was examined. The disease-free (DFS) and overall survival (OS) were calculated using the Kaplan-Meier method and tested with the log-rank procedure. Uni- and multivariate analyses for recurrent factors were performed using the Cox proportional hazard model. Results: 1. The HER2 status was classified as follows; HER2-0 in 1,227 cases (12.0%), HER2-low in 7,209 cases (70.6%), and HER2-positive in 1,779 cases (17.4%). In the recurrent cases, HER2-low was observed in 648 cases (66.1%), and in cases treated with NAC, HER2-low was observed in 544 cases (52.7%). 2. The HER2 status significantly correlated with age, tumor size, lymph nodal status, ER, PgR, NG, and the Ki-67 index value. A comparison between HER2-low and HER2-0 revealed that patients with HER2-low tumors were significantly more likely to be under 50 years of age and had more positive nodes. Moreover, HER2-low was significantly associated with positive ER/PgR, lower NG, and lower Ki-67 index values. 3. There was no significant difference in terms of DFS between the three HER2 groups. However, a difference was observed between the three groups in terms of OS. HER2-0 had the lowest OS rate. Moreover, there was a significant difference in OS after recurrence between HER2-0 and HER2-low. 4. When the DFS for the ER status was examined, a significant difference between the HER2 status in cases with ER < 1.0% and ER>10% was observed. Moreover, the DFS in the HER2-low cases was equivalent to the DFS in the HER2-0 cases. However, the DFS in HER2-low was lower in the ER 1-10% group. Although all the HER2 groups showed a significant difference in OS, HER2-low in the ER 1-10% group had the lowest OS, and HER2-0 in the ER>10% group had the lowest OS and was significantly different from HER2-low in the same group. 5. A multivariate analysis revealed that there was no significant difference between HER2-low and HER2-0 as a prognostic factor after recurrence. 6. The pCR rate for NAC was lowest in the HER2-low group, and the pCR rate in the HER2-low group was significantly lower than the HER2-0 group. 7. The DFS after NAC was significantly better in all the pCR cases, regardless of the HER2 status. However, the DFS was significantly lower in the HER2-low non-pCR cases. Conclusion: HER2-low accounted for 70% of the cases. There were more cases with positive ER/PgR, lower NG, and lower Ki-67 index values in the HER2-low group. The HER2-low group had a significantly better OS than the HER2-0 group. However, the response to NAC was low in the HER2-low group and this group had the poorest prognosis among all the non-pCR cases. These findings indicate that HER2-low has a different biology and prognosis compared to HER2-0 and it may be a new subtype. Citation Format: Reiki Nishimura, Yoshitaka Fujiki, Tetsuhiko Taira, Toshiko Miyaki, Shuichi Kanemitsu, Daisuke Yotsumoto, Megumi Teraoka, Junko Kawano, Naomi Gondo, Reiko Mitsueda, Shinichi Baba, Yasuyo Ohi, Yoshiaki Rai, Yoshiaki Sagara, Yasuaki Sagara. The clinicopathological and prognostic significance of HER2-low breast cancer: A comparative analysis between HER2-low and HER2-zero subtypes [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-24-03.

Chemoinformatics and machine learning techniques to identify novel inhibitors of the lemur tyrosine kinase-3 receptor involved in breast cancer.

Breast cancer is still the largest cause of cancer death in women, and around 70% of primary breast cancer patients are estrogen receptor (ER)-positive, which is the most frequent kind of breast cancer. The lemur tyrosine kinase-3 (LMTK3) receptor has been linked to estrogen responsiveness in breast cancer. However, the function of LMTK3 in reaction to cytotoxic chemotherapy has yet to be studied. Breast cancer therapy research remains tricky due to a paucity of structural investigations on LMTK3. We performed structural investigations on LMTK3 using molecular docking and molecular dynamics (MD) simulations of the LMTK3 receptor in complex with the top three inhibitor molecules along with a control inhibitor. Analysis revealed the top three compounds show the best binding affinities during docking simulations. Interactive analysis of hydrogen bonds inferred hotspot residues Tyr163, Asn138, Asp133, Tyr56, Glu52, Ser132, Asp313, and Asp151. Some other residues in the 5-Å region determined strong alkyl bonds and conventional hydrogen bond linkages. Furthermore, protein dynamics analysis revealed significant modifications among the top complexes and the control system. There was a transition from a loop to a-helix conformation in the protein-top1 complex, and in contrast, in complexes top2 and top3, the formation of a stabilizing sheet in the C chain was observed, which limited significant mobility and increased complex stability. Significant structural alterations were observed in the protein-top complexes, including a shorter helix region and the creation of some loop regions in comparison to the control system. Interestingly, binding free energies, including MMGB/PBSA WaterSwap analysis estimation, reveals that the top1 complex system was more stable than other systems, especially in comparison to the control inhibitor complex system. These results suggest a the plausible mode of action for the novel inhibitors. Therefore, the current investigation contributes to understanding the mechanism of action, serving as a basis for future experimental studies.

Abstract 121: Gut microbiome association with dietary habits and abemaciclib-induced diarrhea:A multicenter, prospective study

Abstract Background: Abemaciclib, a leading treatment used for HR-positive, HER2-negative metastatic and primary breast cancer patients, often causes diarrhea. Understanding the reasons machinery behind this adverse event leads to reduce the toxicity and improve the quality of life. This study explores a hypothesis that specific gut microbiota profiles are engaged in gastrointestinal toxicities caused by abemaciclib and may be influenced by patients' dietary habits. We assessed it using the Brief Diet History Questionnaire (BDHQ). Materials and Methods: Our research involved collecting blood and stool samples, as well as dietary data through the BDHQ from 39 patients diagnosed with HR-positive, HER2-negative metastatic breast cancer. These were obtained prior to the start of abemaciclib treatment, at the first imaging evaluation, and at either disease progression or treatment discontinuation due to adverse effects. Incidence and severity of diarrhea were evaluated by the Bristol stool scale at baseline, from day 1 to day 14, and at day 90 of treatment. Stool samples were collected at baseline and at day 90 after the start of abemaciclib treatment. We conducted 16S metagenomic sequencing for gut microbiome analysis and used mass cytometry along with RNA-sequencing to profile immune cells. Results: Our findings indicate a significant association between the gut microbiota composition and abemaciclib-induced diarrhea, which also appears to be modulated by dietary patterns. An increase in Dorea was observed with higher Bristol Stool Scale scores, while Bifidobacterium and Sellimonas abundances were inversely related to changes in stool characteristics. The presence of Dorea was also positively associated with the consumption of specific food items such as tea, root vegetables, and dietary minerals. In contrast, Collinsella abundance decreased as the frequency of diarrhea increased and it was associated with the consumption of fried foods and certain fats. Conclusion: The prevalence of diarrhea as a side effect of abemaciclib treatment highlights the need for better management strategies. Our study indicates that gut microbiota, altered by dietary habits, is linked to this adverse effect. The data suggest a possibility of using specific gut bacteria as probiotics to alleviate this condition, pointing towards personalized dietary interventions as a potential avenue for improving treatment tolerance. Citation Format: Yuri Fujimoto, Kosuke Kawaguchi, Yurina Maeshima, Hiroshi Ishiguro, Kazuhiko Yamagami, Sachiko Takahara, Hirofumi Suwa, Masae Torii, Shigenori Nagai, Yasuaki Sagara, Wakako Tsuji, Hiroyasu Yamashiro, Takeshi Kotake, Shinji Fukuda, Kuniaki Saito, Yasuko Yamamoto, Masako Kataoka, Yuki Himoto, Atsushi Yonezawa, Yukiko Fukui, Yuki Nakamura, Wei Li, Sunao Tanaka, Masahiro Takada, Satoshi Morita, Masakazu Toi. Gut microbiome association with dietary habits and abemaciclib-induced diarrhea:A multicenter, prospective study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 121.

Abstract 5914: Non-muscle myosin IIA as a promising therapeutic target in breast cancer

Abstract We aimed to determine the role of non-muscle myosin IIA (NMIIA) in breast cancer using various cancer cell lines including estrogen receptor (ER)+, HER2+ and triple negative breast cancers (TNBC). Myosin heavy chain 9 (MYH9) gene encodes for the heavy chain of the hexameric protein NMIIA. We have recently identified that NMIIA serves as a binding partner for HER3 following the inhibition of the HER family member compared to the vehicle control treatment, as observed in HER3 immunoprecipitates. We checked the basal protein and mRNA levels of NMIIA in different breast cancer cell lines and found higher levels of NMIIA in both HER2+ and TNBC cell lines compared to ER+ cell lines. These data correlate with clinical data of primary breast cancer patients with high MYH9 being less likely in ER+ breast cancer patients and more likely in the PAM50 subtypes basal and HER2 enriched breast cancer patients. By employing a pool of four siRNA targeting MYH9, our data indicated a reduction in proliferation of HER2+ and TNBC cell lines when compared to the control siRNA. We have previously found that loss of MYH9 sensitizes to the HER family inhibitor neratinib treatment as assessed by cell proliferation, colony formation on matrigel, cell migration and invasion. We aimed to determine if pharmacological inhibition of the NMIIA pathway would sensitize to neratinib. RhoA-associated kinase (ROCK) serves as a master regulator of NMIIA activity as it directly phosphorylates the regulatory light chain (RLC) of NMIIA. Pharmacological inhibition of ROCK-NMIIA pathway using the ROCK inhibitor GSK269962A alone or in combination with neratinib reduced the cell proliferation in HER2+ cell lines BT474 and MDA-MB-453 as indicated by MTT and cell proliferation assay. It is well known that HER2-targeted therapies cause the upregulation of HER3. Given our identification of NMIIA as one of the interacting partners of HER3, our focus will be on investigating the NMIIA-HER3 signaling axis to elucidate its contribution to an adaptive response to HER2 inhibition and potential treatment resistance. Furthermore, we will explore strategies to target NMIIA in breast cancer. Citation Format: Wasim Feroz, Rosalin Mishra, Mary Kate Kilroy, Joan T. Garrett. Non-muscle myosin IIA as a promising therapeutic target in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5914.

Abstract 109: Identification of tumor-intrinsic and extrinsic mechanisms of T cell exclusion in estrogen receptor-positive (ER+) breast cancer through integration of bulk and single-cell transcriptome and spatial analysis

Abstract T cells are generally present in low numbers in estrogen receptor-positive (ER+) breast cancer (BC) potentially due to limited antigens or impaired antigen presentation, however defined mechanisms are not fully understood. This study explores the interplay between estrogen receptor signaling (ERS), antigen presentation machinery (APM), and T cell signaling (TC) using diverse datasets, including BC cell lines, TCGA, METABRIC, and clinical trial bulk transcriptomes, single-cell RNA-sequencing of ER+ primary BC, and single-cell spatial multi-plex cyclic immunofluorescence (CyCIF) of primary BC patients. Co-expression analysis of both computationally and manually curated genes in TCGA and METABRIC data unveiled distinct 29-gene ERS and 225-gene combined APM/TC modules with strong inverse correlations in ER+ BC. This inverse correlation was confirmed in independent cohorts. ERS and APM/TC modules were down- and up-regulated, respectively, in response to aromatase inhibitor therapy in ER+ BC patients from the ACOSOG Z1301B trial who demonstrated clinical benefit. Analysis of published single-cell RNA-sequencing data of 20 primary ER+ BC was performed to elucidate cell types that express individual genes in the modules. It confirmed that high ERS activity is associated with reduced T cells, and identified distinct cell types contributing to each module, showing higher ERS activity in tumor cells and higher APM/TC activity in stromal and immune cells. At the cell type level, we found distinct contributions and precise insights of individual genes. The prevalence of ERS activity in tumor cells prompted investigation to determine if the ERS and APM/TC modules were preserved as tumor-intrinsic signaling. Analysis of 54 BC cell lines indicated partially preserved module correlations in cancer cell lines and revealed that the APM/TC module is a contribution of both tumor-intrinsic (e.g., complement and type-I IFN-response), and tumor-extrinsic (e.g., lymphocyte activation) factors. CyCIF analysis of 29 ER+ BC samples was performed to bridge gene signatures with spatial biology and validated that higher ERS activity correlates with lower T cell infiltration. The spatial pattern of T cells varied from immune desert to stromally bound to fully inflamed tumors. Neighborhood analysis revealed increased frequency of CD8 T cells around a tumor cell is associated with elevated MHC I and II in broad immune cells and macrophage subsets, respectively. pTBK1+ macrophages inversely correlated with CD8 T cell frequency and MHC expression in neighboring cells, suggesting an immunosuppressive role. This study uncovers robust and tightly regulated ERS and APM/TC signaling in ER+ patients, unraveling molecular intricacies and offering potential insights for targeted therapeutic interventions. Citation Format: Kenichi Shimada, Yvonne X. Cui, Daniel Michaud, Kelly F. Zheng, Jonathan Goldberg, Ricardo Pastorello, Lukas Kania, Sandra S. McAllister, Sara M. Tolaney, Adrienne Waks, Rinath Jeselsohn, Peter K. Sorger, Judith Agudo, Jennifer L. Guerriero, Elizabeth A. Mittendorf. Identification of tumor-intrinsic and extrinsic mechanisms of T cell exclusion in estrogen receptor-positive (ER+) breast cancer through integration of bulk and single-cell transcriptome and spatial analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 109.

Abstract 7634: HER2 extracellular domain in serum samples from HER2+ metastatic breast cancer patients as a potential biomarker of progression-free survival

Abstract Introduction: The detection of serum biomarkers holds potential for non-invasive methods for early cancer detection, monitoring of disease progression, and assessment of treatment responses leading to earlier interventions that may significantly improve patient outcomes. Human epidermal growth factor receptor 2 (HER2) overexpression plays a key role in the prognosis of HER2+ breast cancer (BC). While HER2 is well-established as a cell surface marker, its soluble extracellular domain (ECD) in serum has gained attention as a potential prognostic biomarker. Elevated levels of HER2 ECD (>15ng/ml) have been associated with a poor outcome. However only a small percentage of primary BC patients have levels of HER2 ECD >15ng/ml. Research has suggested that HER2 targeted therapies can influence the rate of HER2 ECD shedding. Therefore, this study aimed to explore the association between circulating HER2 ECD levels with progression-free survival (PFS) and overall survival (OS) in patients with metastatic HER2+ BC. Methods: Matched Pre and post treatment serum samples (n=25) from BC patients enrolled in TH V THL (ICORG (CTRIAL-IE) 11-10/NCT01526369) clinical trial were assessed. Human ErbB2 (HER2) ELISA Kit (Invitrogen) was used to detect levels of soluble HER2 ECD in the serum. Serum levels were stratified as Low (<300pg/ml n=5), Intermediate (300-700pg/ml n=10) or High (>700pg/ml n=10). Patient data correlation was used to assess PFS and OS, Kaplan-Meier survival curves were constructed based on the serum levels of HER2 ECD. Significance p values were determined using log-rank (Mantel-Cox) test. Results: Levels of HER2 ECD detected (94-1730pg/ml) did not exceed 15ng/ml for any sample. There was no significant difference in HER2 ECD levels between treatment arms (TH vs. THL) for PFS (p=0.4685) or OS (p=0.1376). There was no change between the pre and post treatment HER2 ECD serum levels in the samples tested (p=0.344). However, when pre-treatment samples were stratified based on Low, Intermediate or High HER2 ECD levels, there was a significant increase in PFS for patients in the High cohort. Median PFS increased from 8.31 months in the Low cohort to 13.57 months in the Intermediate cohort. The median PFS increased further to 22.24 months in the High cohort (Log rank p=0.0197). The same parameters were applied for the analysis of OS, which also improved as the level of HER2 ECD increased. Median OS increased from 35.19 months (Low) to 68.7 months (Intermediate), with a Median OS not reached for the High cohort (Log rank p=0.077). Conclusions: Patients with HER2 ECD levels above 700pg/ml display a survival advantage in this limited study. Further validation and prospective studies are warranted to fully establish the clinical utility of HER2 ECD as a biomarker in metastatic HER2+ BC. Citation Format: Debbie O'Reilly, Marc Nolan, Ausra Teiserskiene, Bryan T. Hennessy, John Crown, Denis M. Collins. HER2 extracellular domain in serum samples from HER2+ metastatic breast cancer patients as a potential biomarker of progression-free survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7634.

TP53 and/or BRCA1 Mutations Based on CtDNA Analysis as Prognostic Biomarkers for Primary Triple-Negative Breast Cancer.

Precise biomarkers for predicting the therapeutic efficacy of molecularly targeted drugs are limited at the protein level; thus, it has been important to broadly scrutinize individual cancer driver gene mutations for effective cancer treatments. Multiplex cancer genome profiling can comprehensively identify gene mutations that are therapeutic targets using next-generation sequencing (NGS). In addition, circulating tumor DNA (ctDNA) is a DNA fragment released into the blood by tumor cell-derived cell death or apoptosis. Liquid biopsy with ctDNA is a novel clinical test for identifying genetic mutations in an entire population noninvasively, in real-time, and heterogeneously. Although there are several reports on ctDNA, fewer have evaluated ctDNA with NGS before an initial treatment for breast cancer patients. Therefore, we examined whether analyzing tumor-associated gene mutations in primary breast cancer based on ctDNA could serve as a biomarker for prognosis and optimal treatment selection. Ninety-five primary breast cancer patients treated at our department from January 2017 to October 2020 were included. Pretreatment plasma samples were subjected to NGS analysis of ctDNA, and correlations with patients' clinicopathological characteristics were evaluated. Fifty-nine (62.1%) patients were positive for ctDNA. ctDNA tended to be positive in hormone receptor-negative, and TP53 (34%), BRCA1 (20%), and BRCA2 (17%) gene mutations were more frequent. Regarding recurrence-free survival, the prognosis was poor in the TP53 and/or BRCA1 mutation-positive groups, especially in triple-negative breast cancer (TNBC) patients. In conclusion, the results of this study indicate that ctDNA with liquid biopsy could identify the poor prognosis group before treatment among TNBC patients and for those for whom optimal treatment selection is desirable; additionally, optimal treatment could be selected according to the ctDNA analysis results.

RANK and RANKL Expression in Tumors of Patients with Early Breast Cancer

AbstractThe receptor activator of nuclear factor-κB (RANK) pathway was associated with the pathogenesis of breast cancer. Several studies attempted to link the RANK/RANKL pathway to prognosis; however, with inconsistent outcomes. We aimed to further contribute to the knowledge about RANK/RANKL as prognostic factors in breast cancer. Within this study, protein expression of RANK and its ligand, RANKL, in the tumor tissue was analyzed in association with disease-free survival (DFS) and overall survival (OS) in a study cohort of patients with early breast cancer.607 samples of female primary and early breast cancer patients from the Bavarian Breast Cancer Cases and Controls Study were analyzed to correlate the RANK and RANKL expression with DFS and OS. Therefore, expression was quantified using immunohistochemical staining of a tissue microarray. H-scores were determined with the cut-off value of 8.5 for RANK and 0 for RANKL expression, respectively.RANK and RANKL immunohistochemistry were assessed by H-score. Both biomarkers did not correlate (ρ = −0.04). According to molecular subtypes, triple-negative tumors and HER2-positive tumors showed a higher number of RANK-positive tumors (H-score ≥ 8.5), however, no subtype-specific expression of RANKL could be detected. Higher RANKL expression tended to correlate with a better prognosis. However, RANK and RANKL expression could not be identified as statistically significant prognostic factors within the study cohort.Tumor-specific RANK and RANKL expressions are not applicable as prognostic factors for DFS and OS, but might be associated with subtype-specific breast cancer progression.

Stereotactic body radiation therapy (SBRT) for the treatment of primary breast cancer in patients not undergoing surgery

PurposeThe purpose was to explore the role of stereotactic body radiation therapy (SBRT) in providing local control (LC) for primary breast cancer in patients unable to undergo surgery. Materials/methodsBetween 2015 and 2019, 13 non-surgical candidates with 14 lesions were treated with SBRT for primary breast cancer. In 4 cases, SBRT was used after whole breast radiation therapy (WBRT; 40–50 Gy/20–25 fractions). SBRT dose was 30–40 ​Gy in 5 fractions for patients treated with SBRT alone and 25–32 ​Gy in 4–5 fractions for those treated with SBRT ​+ ​WBRT. LC and overall survival (OS) were estimated using Kaplan-Meier curves. Response was also assessed using RECIST guidelines. ResultsMedian follow-up was 32 (range: 3.4–70.4) months. Imaging at median 2.2 (0.6–8.1) months post-SBRT showed median 43.2 ​% (range: 2–100 ​%) decrease in the largest diameter and median 68.7 ​% (range: 27.9–100 ​%) SUV reduction. There were 3 cases of local progression at 8.7–10.6 months. Estimated LC was 100 ​% at 6 months and 71.6 ​% at 12, 24 and 36 months.Estimated median OS was 100 ​% at 6 months, 76.9 ​% at 12 months, and 61.5 ​% at 24 and 36 months. Acute toxicity (n ​= ​13; 92.9 ​%) included grade (G)1 (n ​= ​8), G2 (n ​= ​4), and G4 (necrosis; n ​= ​1). Late toxicity included G2 edema (n ​= ​1) and G4 necrosis (n ​= ​2, including 1 consequential late effect). Only patients treated with SBRT ​+ ​WBRT experienced acute/late G4 toxicity, managed with resection or steroids. ConclusionsSBRT to primary breast cancer resulted in good LC in non-surgical/metastatic patients. Although necrosis (n ​= ​2) occurred in the SBRT ​+ ​WBRT group, it was successfully salvaged.

Abstract A027: Detecting and modeling frequency-dependent evolution in serially passaged primary triple negative breast cancer patient derived xenografts

Abstract Tumor evolution is a contributing factor to most failed cancer treatments. The intratumor heterogeneity of cellular phenotypes found in the tumor microenvironment acts as an evolutionary substate for cancer cells during tumorigenesis, subsequent growth, and after the patient is in the clinic. Selective forces imposed by certain medications can cause the emergence of a tumor with a resistant phenotype. Chemotherapies that target rapidly dividing cells will select for slower dividing ones which are less sensitive to such agents. However, many selective pressures acting on the tumor microenvironment are yet to be elucidated. For example, the effect one cancer cell has on another’s growth through competitive (i.e., the struggle for resources) or cooperative (e.g., exchange of growth factors) interactions remains poorly understood. Our central hypothesis is that cancer cells with distinct karyotypes will have a varying growth rate influenced by the karyotype landscape of the entire tumor. That is, we expect the fitness of a cancer cell to be largely determined by its karyotype and the karyotypes of its neighbors. Thus, we predict that frequency-dependent selection has a significant impact on clonal evolution in cancer. To test this, we have developed two novel methods for respectively identifying likely instances of frequency-dependent selection and modeling the long-term evolutionary trajectory in such cases. To detect frequency-dependent effects, we investigate the relationship between the frequency of one clone and the growth rate of all others (including itself). If a statistically significant correlation can be found, we proceed to modeling clonal evolution. To do this, we use a penalized least squares method and find the best-fitting parameterization of the replicator equation to the clonally resolved frequency data. This provides us with a payoff matrix describing the intensity of competition between each pair of clones. Furthermore, it allows us to model the long-term evolutionary dynamics of the tumor and to make predictions regarding co-existence of clones or clonal sweeps. Recently, investigators serially passaged primary triple negative breast cancer (TNBC) patient derived xenograft (PDX) tumors in NRG mice for over a year, inferring clonal frequencies at multiple timepoints using single cell whole genome (scWGS) and RNA sequencing (scRNA-seq). From this data, we were able to detect statistically significant frequency-dependent effects in the majority of serially passaged PDX tumors. Of these, most are predicted to result in a clonal sweep. Three of the PDX tumors were treated with cisplatin which revealed clone-specific drug response. This presents an opportunity for adaptive therapy scheduling which takes advantage of fitness tradeoffs under different contexts. A greater understanding of the effects frequency-dependent selection has on tumor evolution will contribute to the design of therapies intended to preclude or delay the emergence of resistance to treatment. Citation Format: Thomas A. Veith, Richard Beck, Noemi Andor. Detecting and modeling frequency-dependent evolution in serially passaged primary triple negative breast cancer patient derived xenografts [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr A027.

Independent Validation of the BRENDA-Score Breast Cancer Prognosis Prediction Tool In Chinese Patients

BackgroundThe BRENDA-Score was developed and used to predict the prognosis of patients with breast cancer (BC). This study was performed to validate the use of this tool in Chinese patients with primary invasive BC patients. MethodsPatients underwent surgery for BC from January 2009 to December 2016. Discrimination was assessed by the area under the receiver operating characteristic (ROC) curve (AUC). Calibrations were assessed by comparing predicted and observed 5-year and 10-year metastasis-free survival (MFS) in the overall cohort and patient subgroups. ResultsA total of 2029 BC patients were enrolled. Kaplan–Meier analysis revealed significant differences in MFS risk groups (log-rank test P < .01). ROC analysis showed good accuracy for 5-year MFS (AUC 0.779) and fair accuracy for 10-year MFS (AUC 0.728). The BRENDA-Score accurately predicted 5-year and 10-year MFS in the entire cohort and in all other predefined subgroups, except for the 5-year MFS in the subgroup aged<40 years, which was overestimated (differences between the predicted and observed MFS were 6.7%, P < .05). The 5-year MFS rates of ER- positive and ER-negative patients were 90.9% and 80.6%, respectively (P < .05). The 10-year MFS rates of ER-positive and ER-negative patients were 78.0% and 73.7%, respectively (P = .25). ConclusionsThe BRENDA-Score accurately predicted 5-year and 10-year MFS. The results showed good validity, transportability, and potential clinical value. However, the results for 5-years MFS should be interpreted carefully in patients aged <40 years. After 10 years the value of the ER as a prognostic factor was less important.

Endosomal protein expression of γ1-adaptin is associated with tumor growth activity and relapse-free survival in breast cancer.

γ1-Adaptin is a subunit of adaptor protein complex-1 (AP-1), which regulates intracellular transport between the trans-Golgi network (TGN) and endosomes. Since expression levels of AP-1 subunits have been reported to be associated with cell proliferation and cancer malignancy, we investigated the relationships between the immunohistochemical expression of γ1-adaptin and both clinicopathological factors and relapse-free survival (RFS) in breast cancer tissue. SK-BR-3 cell line depleted of γ1-adaptin was used for cell proliferation, migration, and invasion assay. Intracellular localization of γ1-adaptin was examined with immunohistochemistry (IHC) using an antibody against γ1-adaptin, and with double immunohistofluorescence (IHF) microscopy using markers for the TGN and endosome. γ1-Adaptin intensities in IHC samples from 199 primary breast cancer patients were quantified and assessed in relation to clinicopathological factors and RFS. Cell growth, migration, and invasion of SK-BR-3 cells were significantly suppressed by the depletion of γ1-adaptin. Although the staining patterns in the cancer tissues varied among cases by IHC, double IHF demonstrated that γ1-adaptin was mainly localized in EEA1-positive endosomes, but not in the TGN. γ1-Adaptin intensity was significantly higher in the tumor regions than in non-tumor regions. It was also higher in patients with Ki-67 (high), ER (-), PgR (-), and HER2 (+). Among subtypes of breast cancer, γ1-adaptin intensity was higher in HER2 than in luminal A or luminal B. The results of the survival analysis indicated that high γ1-adaptin intensity was significantly associated with worse RFS, and this association was also observed in group with ER (+), PgR (+), HER2 (-), Ki-67 (high), or luminal B. In addition, the Cox proportional hazards model showed that high γ1-adaptin intensity was an independent prognostic factor. These results suggest that the endosomal expression of γ1-adaptin is positively correlated with breast cancer malignancy and could be a novel prognostic marker.

Increased risk of contralateral breast cancer for BRCA1/2 wild-type, high-risk Korean breast cancer patients: a retrospective cohort study

BackgroundThis study aimed to investigate the contralateral breast cancer (CBC) recurrence rate in Korean breast cancer patients according to their BRCA1/2 germline mutation status, focusing particularly on the CBC recurrence risk in BRCA1/2 negative (BRCAx) patients.MethodsWe conducted a retrospective study on 13,107 primary breast cancer patients. The patients were divided into high-risk and low-risk groups for hereditary breast cancer based on the Korean National Health Insurance Service’s eligibility criteria for BRCA1/2 germline mutation testing. The high-risk group was further categorized into the BRCAmutation group, the BRCAxgroup, and the not tested group. We evaluated the overall survival and cumulative risk of developing CBC in these patients.ResultsAmong 4494 high-risk patients, 973 (21.7%) underwent genetic testing for BRCA1/2 germline mutation, revealing mutations in 158 patients (16.2%). We observed significant overall survival differences across all four groups, with the high-risk, not-tested group demonstrating notably worse overall survival (p < 0.001). However, when adjusted for other prognostic factors, there was no significant differences in hazard ratio of death between the four groups. The cumulative risk of CBC also varied among the groups. Patients with BRCA1/2 mutations showed a 7.3-fold increased risk of CBC compared to the low-risk group (95% CI 4.11–13.0, p < 0.001). Interestingly, BRCAx patients also demonstrated a significantly higher risk of CBC (HR 2.77, 95% CI 1.76–4.35, p < 0.001). The prognostic importance of the BRCAx for CBC recurrence persisted after adjusting for the age and subtype, but became insignificant when the family history of breast cancer was adjusted.ConclusionBreast cancer patients who are at high risk of hereditary breast cancer but with wild-type BRCA 1/2 genes (BRCAx) have increased risk of developing contralateral breast cancer when compared to the low-risk patients. More careful surveillance and follow-up can be offered to these patients especially when they have family history of breast cancer.

Nomogram predicts survival and surgical benefits for patients with breast cancer with initial bone metastasis: A population-based study.

Primary stage IV breast cancer is associated with a poor prognosis. At present, the value of local surgical treatment for patients with stage IV breast cancer remains uncertain; therefore, treatment principles remain controversial. Because of the high heterogeneity of these patients, it is often difficult to evaluate their prognoses. As a result, this study aimed to establish a prognostic nomogram to evaluate the prognosis of patients with breast cancer experiencing primary bone metastasis. The clinical characteristics and follow-up data of patients with primary breast cancer and bone metastasis from 2010 to 2018 were collected from the Surveillance, Epidemiology, and End Results database and from 2013 to 2021 at the Peking Union Medical College Hospital. Patients were divided into training and validation groups. Multivariate Cox regression analysis was used to identify the independent prognostic variables for predicting cancer-specific survival (CSS). On the basis of these independent risk factors, a nomogram was developed and used calibration curves to evaluate its accuracy. Patients were divided into three risk groups according to their scores and surgery-related survival curves plotted using the log-rank test. Overall, 6372 patients were included, with 6319 from the Surveillance, Epidemiology, and End Results database and 53 from the Peking Union Medical College Hospital Breast Surgery Department. Multivariate analysis showed that age, race, marital status, grade, tumor stage, estrogen receptor status, progesterone receptor status, human epidermal growth factor receptor 2 status, and burden of other metastatic lesions were all associated with CSS. Based on these results, a nomogram that predicted the 1-, 3-, and 5-year CSS rates in patients with primary breast cancer and bone metastasis (concordance index > 0.69) was developed. After dividing patients into low-risk, high-risk, or super-high-risk groups based on nomogram scoring criteria, survival analysis revealed that patients in the low- and high-risk groups had significant survival benefits from primary focal surgery. Independent risk factors for primary breast cancer in patients with bone metastasis were analyzed and a nomogram established to predict CSS. The prognostic tool derived in this study can assist clinicians in predicting the survival and surgical benefits of these patients through scoring, thereby providing further guidance for treatment strategies.

NK cell-triggered CCL5/IFNγ-CXCL9/10 axis underlies the clinical efficacy of neoadjuvant anti-HER2 antibodies in breast cancer

BackgroundThe variability in responses to neoadjuvant treatment with anti-HER2 antibodies prompts to personalized clinical management and the development of innovative treatment strategies. Tumor-infiltrating Natural Killer (TI-NK) cells can predict the efficacy of HER2-targeted antibodies independently from clinicopathological factors in primary HER2-positive breast cancer patients. Understanding the mechanism/s underlying this association would contribute to optimizing patient stratification and provide the rationale for combinatorial approaches with immunotherapy.MethodsWe sought to uncover processes enriched in NK cell-infiltrated tumors as compared to NK cell-desert tumors by microarray analysis. Findings were validated in clinical trial-derived transcriptomic data. In vitro and in vivo preclinical models were used for mechanistic studies. Findings were analysed in clinical samples (tumor and serum) from breast cancer patients.ResultsNK cell-infiltrated tumors were enriched in CCL5/IFNG-CXCL9/10 transcripts. In multivariate logistic regression analysis, IFNG levels underlie the association between TI-NK cells and pathological complete response to neoadjuvant treatment with trastuzumab. Mechanistically, the production of IFN-ɣ by CD16+ NK cells triggered the secretion of CXCL9/10 from cancer cells. This effect was associated to tumor growth control and the conversion of CD16 into CD16-CD103+ NK cells in humanized in vivo models. In human breast tumors, the CD16 and CD103 markers identified lineage-related NK cell subpopulations capable of producing CCL5 and IFN-ɣ, which correlated with tissue-resident CD8+ T cells. Finally, an early increase in serum CCL5/CXCL9 levels identified patients with NK cell-rich tumors showing good responses to anti-HER2 antibody-based neoadjuvant treatment.ConclusionsThis study identifies specialized NK cell subsets as the source of IFN-ɣ influencing the clinical efficacy of anti-HER2 antibodies. It also reveals the potential of serum CCL5/CXCL9 as biomarkers for identifying patients with NK cell-rich tumors and favorable responses to anti-HER2 antibody-based neoadjuvant treatment.

Prognostic Impact of HER2-Low and HER2-Zero in Resectable Breast Cancer with Different Hormone Receptor Status: A Landmark Analysis of Real-World Data from the National Cancer Center of China.

The prognostic impact of HER2-low on overall survival (OS) and disease-free survival (DFS) in patients with resectable breast cancer (BC) remains controversial, partly resulting from the hormone receptor (HR) status. To investigate the prognostic impact of HER2-low in different HR subgroups. We retrospectively retrieved medical records of treatment-naive primary HER2-low and HER2-zero BC patients who were diagnosed with invasive ductal carcinoma and underwent surgery in the Cancer Hospital of the Chinese Academy of Medical Sciences from January 2009 to September 2017 (n = 7371). We compared the clinicopathologic features and performed Cox regression and landmark survival analyses to explore the prognostic impact of HER2-low on survival outcomes during distinct post-surgery intervals-36 months, 60 months, and 120 months. HER2-low BC, compared to HER2-zero BC, exhibited less aggressive clinicopathologic features, such as smaller invasion size, lower grade, increased nerve invasion, higher HR positivity, and a higher proportion of low-Ki67 cases. In the HR-positive subgroup, HER2-low demonstrated improved OS (p = 0.046) and DFS (p = 0.026) within 60 months. Conversely, HER2-low displayed worse DFS (p = 0.046) in the HR-negative subgroup after 36 months from surgery. The findings remained robust in uni- and multi-variable Cox models. HER2-low BCs manifested less aggressive clinicopathologic features than the HER2-zero cases. The prognostic impact of HER2-low in resectable BCs exhibits variability contingent upon the patients' HR status.