Luminal HER2 Research Articles

Abstract P4-02-25: Analysis of prognosis in different subtypes of invasive lobular carcinoma using a National Cancer Database Breast Cancer Registry of Japan

Abstract [Introduction] Invasive lobular carcinoma (ILC) has different pathological and clinical features from invasive ductal carcinoma (IDC). ILC has more likely to be hormone receptor (HR) positive, and several studies reported that the prognosis of ILC was better than IDC. However, ILC also has different prognosis according to the subtypes as IDC does, and better prognosis of ILC might depend on their high HR positivity. Additionally, there are many reports that chemotherapy (CT) does not improve the prognosis of ILC due to the high positivity of HR. Therefore, we compared the prognosis of ILC and IDC in the same subtypes and considered necessity of CT for luminal ILC. ILC usually constitutes small population of invasive breast cancer. Thus, we have planed the analysis by using the Breast Cancer Registry (BCR) run on the National Cancer Database (NCD) in Japan. [Methods] 318,338 breast cancer patients were registered in BCR between 2004 and 2012. We selected 250,736 patients who were diagnosed as ILC or IDC. Patients with distant metastasis, those who did not receive surgery, and those who received preoperative therapy, and those who had bilateral breast cancer were excluded, and it resulted in 207,428 patients. Of these cases, the cases with 10-year follow-up data were 136,654, and we examined 5,705 ILC and 130,949, IDC. Because it was presumed that there are differences in pathological and clinical characteristics between ILC and IDC, we have planned to make the matched cohorts by using exact matching for comparing their prognosis. To evaluate the prognosis of each subtype, we compared DFS and OS for IDC and ILC in each subtype. To evaluate the effect of CT in luminal ILC, we corrected the data of luminal ILC with pT2N0M0 or pT1-2N1M0 patients and compared DFS and OS between endocrine therapy (ET) only group and ET+CT group. DFS was defined as the time from surgery to local or distant recurrence or death from any cause. OS was defined as the time between the surgery and the death from any cause. Peason’s Chi squared test was used to identify the characteristics. Survival curves were constructed by Kaplan-Meier method and were compared by log-rank test. [Results] We made the matched cohort by using exact matching and we identified 5,633 ILC and 5,633 IDC for prognosis analysis. In overall subtypes, the 10-year DFS of ILC was poor than those of IDC (76.56% vs 79.14%, p=0.04). In the analysis by each subtype, there was no statistical difference in DFS for luminal HER2, HER2, and TN cohorts, however luminal ILC had statistically significant poor DFS than luminal IDC (78.04% vs 81.17%, p< 0.01). The analysis of 10-year OS showed similar results, and there were no differences in the OS of luminal HER2, HER2 and TN cohorts between ILC and IDC. However, ILC had worse OS than IDC in luminal cohort (85.95% vs 89.13%, p< 0.01). To evaluate the effect of CT in luminal ILC, we made the matched cohort and we identified 95 luminal IDC and 95 luminal ILC in pT2N0 cohort, and 83 luminal IDC and 83 luminal ILC in pT1-2N1 cohort for the analysis. In pT2N0 cohort, the 10-year DFS was 82.12% in ET+CT group and 87.35% in ET only group (p=0.99). The OS of the ET+CT and the ET only group was 93.48% and 94.04% (p=0.88). In pT1-2N1 cohort, the ET only group had 54.17% and the ET+CT group had 77.03% of DFS (p=0.34). The OS in the ET only group and the ET+CT group was 61.96% and 94.81% (p=0.01). [Discussion] Although luminal HER2, HER2 and TN cohorts had no differences in prognosis between ILC and IDC, luminal ILC had a poor prognosis than luminal IDC. Therefore, luminal ILC needs stronger approach to improve their prognosis. And it was suggested that chemotherapy is effective for recurrent high-risk luminal ILC such as those with positive lymph node metastasis. [Conclusion] ILC had worse prognosis than IDC in luminal cohort, however it was comparable in luminal HER2, HER2, TN cohorts. A new strategy of treatments for luminal ILC might be needed to improve their prognosis. Citation Format: Yayoi Adachi, Sota Asaga, Hiraku Kumamaru, Yutaka Yamamoto, Shigeru Imoto, Hiromitsu Jinno. Analysis of prognosis in different subtypes of invasive lobular carcinoma using a National Cancer Database Breast Cancer Registry of Japan [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-02-25.

Abstract P1-05-30: Concordance of preoperative breast MRI finding with definitive postoperative pathology report, after neoadjuvant systemic treatment in patients with breast cancer

Abstract Neoadjuvant, i.e. preoperative, systemic antineoplastic treatment (NAT), in patients with breast cancer enables in vivo monitoring of tumor response to applied therapy, tailoring treatment in real –time accordingly, sparing surgical procedures, better quality of life for patients and implies better patient survival for particular patient, if a pathological complete response (pCR) to treatment is achieved. Use of MRI in monitoring response to NAT has shown in various studies sensitivity and specificity of at least 70% in the detection of residual disease, with a high positive and negative predictive value. Studies have shown higher accuracy in predicting pCR in HER2 positive tumors, and a higher rate of false negative results in HER2 negative tumors. Here we report findings of our pilot project where we tested the accuracy of the MRI, and the concordance of preoperative MRI findings after NAT, with the definitive pathology report after the surgery was performed, in breast cancer patients with different disease biology, in the real clinical practice. The focused pathological supstrate was the primary tumor in the breast. For the simplicity of this pilot analysis, we did not include here the status of the axilla, which will be included in our larger analysis pending. We performed our analysis on a cohort of 200 breast cancer patients who underwent NAT, in our institution, University Hospital for Tumors, in Zagreb, Croatia. Median age of the analyzed patient cohort was 62 years. The representation of individual breast cancer intrinsic subtype surrogates was as follows: HER2 nonluminal tumor 23.5% (47/200), triple negative breast cancer 21.5% (43/200), luminal HER2 positive 22.5% (45/200) and luminal HER2 negative 32.5% (65/200). According to MRI of the primary tumor in the breast, radiological complete response (rCR) to NAT was achieved in 46.5% (93/200) of patients, and the finding of residual tumor was described in 53.5% (107/200) of patients. Postoperatively, pathology report of the primary breast tumor showed pCR in 29% (58/200) of patients, and residual disease in 71% (142/200) of cases. The overall concordance of MR and pathology reports was 62.4% in the assessment of complete response, and 75.35% in the assessment of residual disease. Analyzed according to subgroups, results are as follows: in the cohort of patients with HER2 nonluminal tumors, concordance of MRI and pathology report in the assessment of complete response was 88%, while for residual disease concordance was 70%; in the cohort with triple-negative breast cancer patients, concordance of MRI and pathology report in the assessment of complete response was 83%, and residual disease 87.8%; in the group with luminal HER2-positive breast cancer concordance of MRI and pathology report in assessing complete response, as well as residual disease, was 97%; while in the group with luminal HER2-negative breast cancer, concordance of MRI and pathology report findings in assessing complete response was only 50.5%, and residual disease 77%. Results of our analysis showed relatively high overall concordance between MRI and pathology findings, which is in line with results of large studies worldwide and confirms MRI as a good method in monitoring response to NAT in breast cancer patients. By subgroup analysis, patients with luminal HER2-negative tumors are distinguished. This group has the lowest prevalence of complete response overall, as well as the lowest concordance of MRI and pathology report findings in the detection of these cases. This confirms the weaker response of this type of tumor to neoadjuvant treatment, but also indicates the need for additional caution when analyzing MRI findings in these patients, as well as for considering additional diagnostic arsenal, complementing the standardly – utilised MRI. Citation Format: Ana Tecic Vuger, Melita Peric Balja, Petra Jaksic, Petra Linaric, Mirjana Pavlovic Mavic, Ljubica Vazdar, Robert Separovic. Concordance of preoperative breast MRI finding with definitive postoperative pathology report, after neoadjuvant systemic treatment in patients with breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-05-30.

Abstract P5-14-13: Benefits of Oncotype DX genomic screening in a geriatric vs. non-geriatric cohort. Analyzing key factors in therapy decision making process

Abstract Introduction In early luminal HER2 negative breast cancer Oncotype DX® Recurrence-Score (RS) has been broadly validated in pre- and postmenopausal patients and can predict prognosis and benefit of chemotherapy. Its value in elderly breast cancer populations has not been deeply addressed. This study analyses clinical and pathologic factors, RS distribution and outcomes in an elderly vs. non-elderly breast cancer population with the purpose of establishing RS added value to the therapy decision-making process in a geriatric cohort. Methods This is a retrospective analysis of available data from patients with early luminal HER2 negative breast cancer treated at the University Hospital Basel and the Cantonal Hospital Baselland between 2010 and 2022. Cohort A (A) consists of patients < 70 years old and cohort B (B) of patients aged ≥70 years. At moment of decision for adjuvant treatment all patients had known RS result. Results A and B included 266 (81%) and 60 (19%) patients, respectively. The median age in A was 55.2 and in B, 74 years. The following clinical and pathologic factors were different in B vs. A: co-morbidities (55 % vs. 35%, p=0.005), BMI (BMI≥25 (overweight vs. normal, p=0.023), tumor size (31.3 mm vs 23.6 mm p=0.021). Geriatric patients also tended to have a clinically higher risk status (83% vs. 70%; p=0.05). There was a trend for a higher mastectomy rate in B vs. A (41.7% vs. 29%, p=0.065), significantly less radiotherapy use (65% vs. 81%, p=0.009) and more osteo-oncologic treatment (61% vs 43%, p=0.013). RS distribution was not significantly different between cohorts (A vs. B was: RS 1-15: 44.3% vs 41.7%, RS 16-25 41.2% vs 35% and RS≥26 14.5% vs 23.3%; p=0.234). Adjuvant chemotherapy was performed in 11.5% of B and 22.9% of A (p=0.116) and adjuvant endocrine therapy in 98.3% of B vs. 93.5% of A (p=p=0.214). Tumor board suggested systemic treatment was not implemented in 22% vs 15 %, (B vs. A; p =0.087). With a median follow-up of 36.6 months, recurrence rate was higher, but not statistically significant in B vs. A (10% vs 6%, p=0.259). Relapse rate was higher with RS≥26 vs. RS 0-25 (13.5% in B vs. 5.7% in A; p=0.043). Conclusions Older breast cancer patients tend to have higher clinical risk status, more co-morbidities and higher BMI. RS distribution was not significantly different between the two cohorts, however higher RS did pose a higher relapse rate for older patients in our cohort. Although RS based guidelines, still apply in therapy decision making in the case of geriatric breast cancer patients, clinical practice points to a rather individualized treatment in which all clinical and pathological factors are weighted. Citation Format: Elena D Chiru, Cvetka Grasic Kuhar, Anton Oseledchyk, Christian Kurzeder, Marcus Vetter. Benefits of Oncotype DX genomic screening in a geriatric vs. non-geriatric cohort. Analyzing key factors in therapy decision making process [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-14-13.

Amide proton transfer (APT) imaging of breast cancers and its correlation with biological status

PurposeTo assess the usefulness of amide proton transfer (APT) imaging to predict the biological status of breast cancers. MethodSixty-six patients (age range 31–85 years, mean 58.9 years) with histopathologically proven invasive ductal carcinomas of 2 cm or larger in diameter were included in this study. 3D APT weighted imaging was conducted on a 3 T scanner. Mean APT signal intensity (SI) was analyzed in relation to biological subtypes, Ki-67 labeling index, and nuclear grades (NGs). ResultsThe triple-negative (TN) cancers (n = 10; 2.75 ± 0.42%) showed significantly higher APT SI than the luminal type cancers (n = 48; 1.74 ± 0.83) and HER2 cancers (n = 8; 1.83 ± 0.21) (P = 0.0007, 0.03). APT SI had weakly positive correlation with the Ki-67 labeling index (r = 0.38, P = 0.002). The mean APT SIs were significantly higher for high-Ki-67 (>30%) (n = 31; 2.25 ± 0.70) than low-Ki-67 (≤30%) cancers (n = 35; 1.60 ± 0.79) (P = 0.0007). There was no significant difference in the APT SIs between NG 1–2 (n = 31; 1.71 ± 0.84) and NG 3 (n = 35; 2.08 ± 0.76%) cancers (P = 0.06). ConclusionsTN and high-Ki-67 breast cancers showed high APT SIs. APT imaging can help to predict the biological status of breast cancers.

Contemporary evaluation of estrogen receptor and progesterone receptor expression in breast cancer-associated stroma.

To investigate nuclear estrogen receptor α (ERα) and progesterone receptor (PR) immunohistochemistry (IHC) patterns in the stroma surrounding invasive carcinoma and assess associations with clinicopathologic features. A retrospective database search (1/2017-12/2020) identified breast core biopsies with invasive carcinoma. ERα/PR IHC expression in invasive carcinoma and stromal cells was categorized visually as positive (> 10%), low positive (1-10%) or negative (< 1%). Tumors were divided into 4 subtypes by IHC: Luminal, Luminal HER2, HER2 enriched, and triple negative. Clinicopathologic features associated (univariate p-value < 0.15) with ERα/PR stromal expression were investigated further using stepwise multivariable logistic regression. Of 1512 biopsies, 1278 had accessible IHC. 55.6% (711/1278) and 10.4% (133/1274) of cases showed cancer-associated stromal fibroblast expression of ERα and PR, respectively. Stromal ER positivity was significantly associated with use of the Ventana (with SP1 clone) versus Leica (with 6F11 clone) platform and in cases with Luminal cancer subtype. PR stromal expression was significantly associated with Luminal subtype, obesity, and younger age. Expression of ERα and PR in breast cancer-associated stroma showed associations that suggest both biologic and analytic influence. Reproducible expression patterns may inform expansion of ERα/PR guidelines for the assessment of internal controls.

The value of potential immunohistochemical biomarkers and clinicopathological findings in predicting response to neoadjuvant chemotherapy in breast cancer.

Following neoadjuvant chemotherapy (NAC) in breast cancer (BC), complete treatment response is achieved in some patients, while treatment response is limited in others. Predicting non-responder patients can prevent exposure to adverse effects associated with chemotherapeutic agents and delays in selecting other treatment modalities. In this study, we aimed at identifying predictive factors related to tumor regression in patients with BC who received NAC. This single-center cohort included 91 patients with BC who underwent surgery following NAC based on pretreatment tumor biopsy. According to BC molecular subtype, tumor regression grade (TRG) was determined using the Miller-Payne scoring system in patients who received standard NAC. Immunohistochemical stainings for VEGFR3 and CD44 were applied to needle core biopsies obtained prior to NAC in these patients. Pathological complete response (pCR) was achieved in 20 patients (22%). In univariate analysis, high Ki-67 expression, ER negativity, and HER2 positivity were determined to be predictive factors of TRG (p < 0.05). In multivariate analysis, Ki-67 was the single independent predictor of TRG, with a 1.05-fold effect size. CD44 and VEGFR3 levels did not affect TRG or survival (p > 0.05). There was a significant difference in TRG according to molecular subtype of BC (p < 0.001). The treatment response was 5.5-fold higher in HER2-positive patients compared with HER2-negative patients. pCR rates were significantly higher in TNBC, HER2, and luminal HER2+ subtypes when compared with luminal HER2- subtype. Ki-67 >25% and ER negativity had a favorable effect on TRG after NAC. CD44 and VEGFR3 were not effective in predicting treatment response.

Epidemiology of Breast Cancer in Mexican Women with Obesity as a Risk Factor.

Purpose. Adipose tissue in overweight and obesity shows metabolic imbalance in the function of adipocytes and macrophages, this leads to altered regulation of hunger, lipid storage, and chronic inflammation possibly related to the development of breast cancer. Methods. The study was retrospective of 653 breast cancer patients treated at a tertiary care hospital. Histopathology, hormone receptors, grade, clinical stage, clinical biometry analysis, CEA and CA 15-3 antigens were analyzed. The analyses were performed at diagnosis and at the end of oncological treatments. Results. Mexican women studied and treated for breast cancer have an BMI of 29 from diagnosis and at the end of their cancer treatments. The average age was 52 ± 12 years, 54% in women older than 55 years. Cancer recurrence occurs in any molecular type; however, the common factor was overweight and obesity with 73% vs. 21% in normal weight patients. The most frequent tumor tissue in the population was positive hormone receptors of the luminal type (65%), HER2 (15%), and NT (15%). The analyses of macrophages/lymphocytes (M/L), CEA, and CA 15-3 antigens evaluated in women >55 and <55 years, with and without recurrence are elevated at the end of oncological treatments. Conclusions. The analysis of Mexican women with breast cancer showed a predominance of overweight and obesity at diagnosis and at the end of treatment. A relationship between obesity and cancer recurrence with a low response to treatment due to elevation in Ag CEA and CA 15-3 is suggested. The L/M ratio could be an indicator of inflammation related to adipose tissue since diagnosis.

INHBA is a mediator of aggressive tumor behavior in HER2+\u2009basal breast cancer

BackgroundResistance to HER2-targeted therapeutics remains a significant clinical problem in HER2+ breast cancer patients with advanced disease. This may be particularly true for HER2+ patients with basal subtype disease, as recent evidence suggests they receive limited benefit from standard of care HER2-targeted therapies. Identification of drivers of resistance and aggressive disease that can be targeted clinically has the potential to impact patient outcomes.MethodsWe performed siRNA knockdown screens of genes differentially expressed between lapatinib-responsive and -resistant HER2+ breast cancer cells, which corresponded largely to luminal versus basal subtypes. We then validated hits in 2-d and 3-d cell culture systems.ResultsKnockdown of one of the genes, INHBA, significantly slowed growth and increased sensitivity to lapatinib in multiple basal HER2+ cell lines in both 2-d and 3-d cultures, but had no effect in luminal HER2+ cells. Loss of INHBA altered metabolism, eliciting a shift from glycolytic to oxidative phosphorylative metabolism, which was also associated with a decrease in tumor invasiveness. Analysis of breast cancer datasets showed that patients with HER2+ breast cancer and high levels of INHBA expression had worse outcomes than patients with low levels of INHBA expression.ConclusionsOur data suggest that INHBA is associated with aggressiveness of the basal subtype of HER2+ tumors, resulting in poor response to HER2-targeted therapy and an invasive phenotype. We hypothesize that targeting this pathway could be an effective therapeutic strategy to reduce invasiveness of tumor cells and to improve therapeutic response.

Abstract P4-05-04: Menopausal breast cancer: Bone mineral density (BMD) and prognostic factors

Abstract Aims: Study the relationship between Bone Mineral Density (BMD) before breast cancer and prognostic factors in menopausal breast cancerMethods: Study 340 menopausal breast cancer, BMD before breast cancer and prognostic factors. The bone mineral density was measured using z score femur of dual energy X-ray absorptiometry (DXA), z score was classified between &amp;gt; 1 - &amp;lt; -1 and &amp;gt; -1. Analyze z score with the prognostic factors (tumor size T1 versus T2-3, nodes positive versus negative, histologic grade I vs II-III, hormonal receptor positive versus negative, HER2 positive versus negative, Ki 67 &amp;gt; 20 versus &amp;lt;20, p53 positive versus negative), tumor subtype (Luminal versus No Luminal), bilateral tumor (synchronous, asynchronous) and recurrences. Results: The mean age of the 340 patients was 61 years. Score femur of dual energy X-ray absorptiometry (DXA) was &amp;gt; 1 - &amp;lt; -1 in 284 (84'41%) and &amp;gt; -1 - -3'8 in 53 (15'58) patients. Tumor size was greater than 2 centimeters in 55 16.17%) patients and in 285 (83.82%) patients up to 2 centimeters. Histological Grade (HG) was I in 196 (57.64%), II in 121/35.58) and III in 23 (6.76%) patients. The. z score femur of dual energy X-ray absorptiometry (DXA) was&amp;gt; 1 - &amp;lt; -1 in 284 (84'41%) patients and&amp;gt; -1 - -3'8 in 53 (15'58) patients. Tumor size was greater than 2 centimeters in 55 (16.17%) patients and in 285 (83.82%) patients up to 2 centimeters. Histological Grade (HG) was I in 196 (57.64%), II in 121/35.58) and III in 23 (6.76%) patients. The tumor subtype was Luminal A in 276 (82.65%), Luminal B HER2- in 64 (18.87%), Luminal B HER2 + in 26 (7.66%), HER2 + in 12 (3.52%). and Triple Negative in 12 (3.53%) patients. Recurrences were in. 14 patients. The z score of dual energy X-ray absorptiometry (DXA) before breast cancer &amp;gt; +1 - &amp;lt; -1 was related (p&amp;lt;0'05) to HG I, T1, Luminal tumor subtypes and HER2+ tumor subtypes. It is not related (p=ns) to positive nodes, hormonal receptors (HR), Ki 67, p53 positive and bilateral synchronous and asynchronous tumor. Conclusion. The z score of dual energy X-ray absorptiometry (DXA) before breast cancer can give us information on the prognostic factors of menopausal breast cancer Citation Format: Menopausal breast cancer: Bone mineral density (BMD) and prognostic factors [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-05-04.

CHARACTERISTICS OF RESPONSE TO NEOADJUVANT CHEMOTHERAPY IN PATIENTS WITH AGGRESSIVE BIOLOGICAL SUBTYPES OF STAGE II–III BREAST CANCER. ORIGINAL STUDY

Goal: To analyze the tumor response to NACT in patients with aggressive biological subtypes of stage II–III breast cancer based on the contemporary scoring systems for residual pathological stage evaluation and the residual cancer burden according to the RCB system. Materials and methods: A total of 172 women with stage II–III breast cancer of aggressive biological subtypes (triple negative in 34,3 %; HER2‑positive tumors in 28,5 %; luminal B Her2‑negative BC in 37,2 %) were included in this analysis. The median age of the patients was 47 years (24–81 years); сT2 was the predominant tumor size (65,1 %); 69,8 % of patients had regional lymph node involvement; 62,8 % of patients had G3 tumor; Ki67 ≥ 30 % was found in 90,7 % of cases. All patients received neoadjuvant chemotherapy (NACT) with concomitant anti-HER2 blockade in case of HER2‑positive tumors followed by surgery. Morphological assessment included evaluation of the residual pathological stage and the residual cancer burden according to the RCB system. Results: Total pathological complete response (no evidence of residual invasive tumor in the breast and lymph nodes — tpCR) was observed in 69 of 172 patients (40,1 %), which corresponded to the уpT0N0 pathological stage and RCB class 0. The highest tpCR rate was achieved in patients with HER2‑positive cancer (63 % in non-luminal HER2‑positive subtype and 59.1 % in luminal HER2 + BC) and triple negative cancer (50,8 %). Meanwhile, the tpCR rate in patients with luminal HER2‑negative BC was only 15,6 %, p &lt; 0.0001. The proportions of the RCB classes in the whole sample were 6,4 % (RCB-I), 30,2 % (RCB-II), 23,3 % (RCB-III), and differed significantly between the biological subtypes. RCB class I was nearly absent in the triple negative cancer group (1,7 % only), the residual tumor corresponded to RCB classes II and III in 25,4 % and 23,7 % of cases, respectively. In the HER2‑positive cancer group, the percentage of patients with RCB class I residual tumors was 9,1 % and 11,0 % in luminal and non-luminal cancers, respectively. One of four patients had RCB class II; RCB class III was found only in 9 % of luminal HER2‑positive cancer cases and in no patients with non-luminal HER2‑positive subtype. Most patients with luminal B HER2‑negative BC had RCB II and III: 39,1 % and 37,5 % of cases, respectively, p &lt; 0.0001. Conclusions: patients with aggressive biological BC subtypes differed significantly not only in the rates of the total pathological complete response to NACT, but also in the distribution of residual cancer burden classes, which can be translated into the disease prognosis.

Prognostic Role of Androgen Receptor Expression in HER2+ Breast Carcinoma Subtypes.

HER2+ breast cancer (BC) is an aggressive subtype representing a genetically and biologically heterogeneous group of tumors resulting in variable prognosis and treatment response to HER2-targeted therapies according to estrogen (ER) and progesterone receptor (PR) expression. The relationship with androgen receptors (AR), a member of the steroid hormone’s family, is unwell known in BC. The present study aims to evaluate the prognostic impact of AR expression in HER2+ BC subtypes. A total of 695 BCs were selected and reviewed, AR, ER, PR and HER2 expression in tumor cells were examined by immunohistochemical method, and the SISH method was used in case of HER2 with equivocal immunohistochemical score (2+). A high prevalence of AR expression (91.5%) in BC HER+ was observed, with minimal differences between luminal and non-luminal tumor. According to steroid receptor expression, tumors were classified in four subgroups, including BC luminal and non-luminal HER2+ expressing or not AR. The luminal BC HER2 + AR+ was associated with lower histological grade, lower tumor size, higher PR expression and lower HER2 intensity of expression (2+). Also, the non-luminal tumors AR+ showed lower tumor size and lower prognostic stage but frequently higher grade and higher HER2 intensity of expression (3+). These findings should suggest a different progression of luminal and non-luminal tumors, both expressing AR, and allow us to speculate that the molecular mechanisms of AR, involved in the biology of BC HER2 + AR+, differ in relation to ER and PR expression. Moreover, AR expression may be a useful predictor of prognosis for overall survival (OS) in HER2+ BC subtypes. Our findings suggest that AR expression evaluation in clinical practice could be utilized in clinical oncology to establish different aggressiveness in BC HER2+ subtypes.

Glucose and glutamine metabolism-related protein expression in breast ductal carcinoma in situ.

Glucose and glutamine metabolism is involved in important tumor mechanisms. Metabolism-related protein expression has been previously reported to predict tumor prognosis. We aimed to investigate glucose and glutamine metabolism-related protein expression and its implication in breast ductal carcinoma in situ (DCIS). A tissue microarray was prepared for 205 DCIS cases. Glucose and glutamine metabolism-related proteins were immunostained. Based on the results of estrogen receptor, progesterone receptor, human epidermal growth factor receptor (HER)-2, and Ki-67, DCIS was classified into the luminal type, HER-2 type, and triple-negative breast cancer (TNBC). DCIS stroma was classified into non-inflammatory and inflammatory types per stromal histology. DCIS (N=205) was classified into luminal type (n=112), HER-2 type (n=81), and TNBC (n=12). Hexokinase II (p=0.044), GLS (p=0.003), and SLC7A5 (p<0.001) expression rates were the highest in TNBC. Inflammatory type stroma showed higher SLC7A5 (p<0.001) and SLC7A11 (p=0.008) expression rates than non-inflammatory type stroma. In summary, DCIS demonstrated differential expression of metabolism-related proteins according to the molecular subtype and stromal features. TNBC showed the highest glucose and glutamine metabolism-related protein expression, and inflammatory type stroma showed higher glutamine metabolism-related protein expression than non-inflammatory type stroma.

Tolerability of Eribulin and correlation between polymorphisms and neuropathy in an unselected population of female patients with metastatic breast cancer: results of the multicenter, single arm, phase IV PAINTER study

BackgroundMetastatic breast cancer (MBC) is an incurable disease and its treatment focuses on prolonging patients’ (pts) overall survival (OS) and improving their quality of life. Eribulin is a microtubule inhibitor that increases OS in pre-treated MBC pts. The most common adverse events (AEs) are asthenia, neutropenia and peripheral neuropathy (PN).MethodsPAINTER is a single arm, phase IV study, aimed at evaluating the tolerability of eribulin in MBC pts. Secondary objectives were the description of treatment efficacy and safety, the assessment of the incidence and severity of PN and its association with genetic polymorphisms. Genomic DNA was isolated from blood samples and 15 Single Nucleotide Polymorphisms (SNPs) were genotyped by Taqman specific assays. The association between PN and SNPs were evaluated by Fisher exact test.ResultsStarting from May 2014 until June 2018 180 pts were enrolled in this study by 20 Italian centers. 170 of these pts could be evaluated for efficacy and toxicity and 159 for polymorphisms analysis. The median age of pts was 60 years old and the biological subtypes were luminal type (64.7%), Her2 positive (18.3%) and triple negative (17%). Pts were pretreated with a median of 5 lines for MBC. The median follow up of this study was 15.4 months with a median number of 4.5 cycles administered (minimum–maximum 1–23). The median overall survival was 12 months. 48.8% of pts experienced a dose reduction, mainly for neutropenia (23.9%) and liver toxicity (12%). 65 pts (38.2%) reported at least one severe toxicity. Neutropenia and neurotoxicity were the most frequent severe AEs (15.3% and 14.7%, respectively); other reported toxicities were osteo-muscular, abdominal or tumor site pain (19.4%), liver toxicity (6.6%), pulmonary toxicity (6.5%) and dermatological toxicity (3.6%). Among the 15 evaluated SNPs, an association with PN was found for rs2233335 and rs7214723.ConclusionsEribulin is a well-tolerated treatment option in MBC. Schedule and dosage modifications were common, but toxicity rarely led to treatment discontinuation. SNPs rs2233335 (G/T and T/T) in the NDRG1 gene and rs7214723 (CC and CT) in the CAMKK1 gene were associated with PN. These findings, if validated, could allow a tailored treatment with eribulin in cancer patients.Trial registration: ClinicalTrials.gov ID: NCT02864030.

Neoadjuvant chemotherapy for HER2-positive breast cancer using dose-consolidated regimens and dual anti-HER2 blockade with pertuzumab and trastuzumab (preliminary results)

The main goal of neoadjuvant chemotherapy (NACT) in aggressive breast cancer (BC) subtypes (triple-negative, HER2-positive) is to achieve complete pathological response (pCR), since it is associated with a significant decrease in the likelihood of recurrence and death. Currently, the standard approach for HER2+ BC stage II–III is NACT with the inclusion of a double anti-HER2 blockade, since this significantly increases the frequency of pCR. To date, it remains unclear whether the intensification of modern anthracycline-taxane-containing regimens of NACT affects the incidence of pCR in different BC subtypes, including HER2-positive, provided that a double anti-HER2 blockade is used.The aim of our prospective observational study from daily clinical practice was to assess the efficacy (according to the RCB system and the frequency of pCR) and tolerability of dose-dense NACT in stage II–III HER2-positive BC.Materials and methods. The study included 86 patients, mean age 45 years (26–74 years), in 96.5% of cases, the tumor was represented morphologically by invasive cancer of a nonspecific type, in 53.5% of the tumors had a positive luminal B HER2 phenotype, in 46.5% – non-luminal HER2+. The majority of patients (67.4%) had locally advanced inoperable breast cancer; in 80.2% of cases, metastatic lesions of regional lymph nodes were determined. NACT included anthracyclines and taxanes: four cycles of AC in a dose-dense regimen (once every 2 weeks), then four cycles of docetaxel 75 mg/m2 once every 3 weeks + trastuzumab + pertuzumab.Results. The frequency of pCR = RCB0 in the entire group was 54.7% (47/86), in locally advanced breast cancer – 55.9%, in operable breast cancer – 51.9%. In the luminal HER2+ subtype, the frequency of pCR was lower than in the non-luminal HER2+ subtype – 43.5% vs 67.5%, however, the differences were statistically insignificant (p = 0.09). The frequency of RCB0–I in ER+ HER2+ subtype was 60.9%, as in ER-HER2+ – 80%. Conclusions. In our study, for the first time, the efficacy of dose-dense NACT in HER2+ breast cancer was assessed; it was shown that the frequency of pCR and RCB0–I correspond to those in standard anthracycline-taxane-containing regimens. In the context of the use of double anti-HER2 blockade, the anthracycline stage, most likely, does not need to be escalated, since this does not lead to an increase in the frequency of complete pathomorphological regressions.

178P Age-related mutational landscape of luminal breast cancers

Breast cancer has afflicted more than 576000 women in 2020, one quarter of whom were younger than 50 years. A worse outcome has been associated with breast cancer at a younger age. In the luminal HER2 negative breast cancer subtype, an interaction between age and chemotherapy has been observed in younger women, consistently across the prospective trials MINDACT, TAILORx, and RxPONDER. The hypothesis that this benefit is due to an indirect effect of chemotherapy on ovarian suppression is debated.

What do we still need to learn on digitally assessed biomarkers?

What do we still need to learn on digitally assessed biomarkers?

Abstract 1075: AXL is a potential druggable target in trastuzumab resistance in HER2+ breast cancer patients

Abstract Introduction HER2+ correlates with aggressive phenotype and poor prognosis. The use of several antiHER2 drugs has dramatically improved prognosis and survival of HER2+ breast cancer (BC) patients. However, ≈20% of these patients will present resistance to antiHER2 therapies and relapse. The purpose of this study is to explore the role of AXL in antiHER2 treatment resistance and its potential as a druggable biomarker in HER2+ BC. Methods We generated 2 trastuzumab (T) resistant models from a HER2+ BC patient. The first one was a PDX derived resistant cell line established by chronic treatment for 6 months with T in vitro (TR1 and TR2). The second resistant model (TR4) was established by chronic treatment with T for 4 months and two serial passages in mice. The prognostic value of AXL was evaluated in primary tumor cohort of HER2+ BC patients treated by standard guidelines (n=51). AXL was also explored in a cohort from PAMELA trial, a neoadjuvant phase II study. Patients were given lapatinib and T for 18 weeks (Luminal-HER2+ patients were additionally given hormonotherapy). Tumor samples were collected at baseline, day 14 and surgery (n= 96). Results PDX resistant cell lines (TR1 and TR2) and resistant tumors (TR4) exhibit upregulation of AXL in comparison to the parental cells (PDX118). In vitro, the combination of an AXL inhibitor (TP-0903) + T resensitized resistant cells to T. In 3D organoids models from TR4, the combination decreased cell number in organoids more than both single agents. In TR4 in vivo model, TP-0903 + T completely abrogate tumor growth for more than 2 months.To validate our preclinical findings, we analyzed the level of AXL in our retrospectively cohort of patients. AXL level was significantly upregulated in patients who relapsed (p&amp;lt;0.0001). Patients with high levels of AXL had significantly shorter disease-free survival (DFS) and overall survival (OS) (log-rank p&amp;lt;0.0001; HR=15.78; 95% CI 3.89-19.80 for DFS; log-rank p=0.013; HR= 5.43; 95% CI 1.35-13.07 for OS). The median DFS and OS were 36 and 77 months in patients with high AXL level, whereas patients with low AXL level presented 92.5 and 92.5 months.To identify early molecular changes induced by dual HER2 blockade in patients with HER2+ disease, AXL was analyzed in PAMELA trial cohort. A significant increase of AXL was detected at day 14 compared to baseline (p=5.8e-20). This effect was observed in both luminal and non-luminal HER2+ BC patients and across all PAM50 subtypes. This rapid response suggests the implication of AXL as a mechanism of antiHER2 resistance. Levels of AXL decreased as long as treatment was on hold at surgery compared to day 14 (p=6.04e-14). Conclusion AXL level was correlated with poor outcome of HER2+ BC patients. On our preclinical models, we showed that combination of TP-0903 and T abrogate tumor growth in acquired resistant models to T in PDXs. We postulate AXL as a promising new therapeutic strategy to overcome resistance to antiHER2 therapies Citation Format: Anna Adam-Artigues, Raimundo Cervera, Enrique Javier Arenas, Fara Brasó-Maristany, Alex Martinez-Sabadell, Eduardo Tormo, Cristina Hernando, Maria Teresa Martinez, Soraya Simon, Jesús Poveda, Octavio Burgués, Ana Rovira, Federico Rojo, Joan Albanell, Begoña Bermejo, Ana Lluch, Pilar Eroles, Aleix Prat, Joaquin Arribas, Juan Miguel Cejalvo. AXL is a potential druggable target in trastuzumab resistance in HER2+ breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1075.

Intra- and inter-observer variability in tumor infiltrating lymphocyte scoring in breast cancer core needle biopsy.

e12626 Background: Morphological evaluation of tumor lymphocyte infiltration (TIL) in breast cancer (BC) is gaining importance in the clinical setting, as it provides good prognostic information. Most institutions adhere to TIL working group guidelines for evaluating TIL, while having to settle on an acceptable error margin due to its subjective nature, which leads to intra and inter-observer scoring discordance. We aimed to analyze both at our institution, using experienced and inexperienced examiners, with a continuous variable scoring system. Methods: 209 BC core needle biopsy (CNB) samples were stained using hematoxylin-eosin. The percentage of stromal TIL was scored using a numerical variable ranging from 1 to 100. The examination group consisted of two experienced pathologists (pathologist A and B) and one inexperienced examiner - a medical oncology resident with a learning process containing study of the TIL working group analysis criteria and about 100 samples analysed together with an experienced pathologist Pathologist A and the resident analyzed the study samples twice, pathologist B once. Intraclass correlation coefficient (ICC) was used to measure overall intra and inter-observer agreement. Statistical analysis was performed using Google Sheets and Python. Results: 203 CNB samples were analysed (6 were excluded due to inadequate quality or an inconclusive diagnosis). Patients were aged 26 to 79 years (median 49). Sample size ranged from 1 to 16 mm (median 8). The proportion of BC subtypes was: luminal A-like 18%, luminal B-like 39%, HER2+ 10%, luminal B-like HER2+ 12%, TNBC 18%, not defined 2%. The highest proportion of high stromal TIL (≥50%) was seen in HER2+ (30%) and TNBC (22%) subtypes, as observed by pathologist A. We found good intra and inter-observer ICC (Table). Conclusions: Acceptable intra and inter-observer variability was observed in experienced pathologists, suggesting that the proposed methodology could reliably be used in clinical practice, research and trials. Interestingly, variability analysis of scores from a trained non-pathologist has also produced good results. However, it is important to note that inexperienced scoring could be prone to errors, for example counting non-lymphocyte cells as such, not recognizing regions of necrosis or sample damage, or not distinguishing between the tumor and peripheral stroma. Intraclass correlation: two-way random, single score (ICC2); pathologist A and resident (R) first and second analysis (A1, A2, R1, R2); pathologist B analysis (B1). Interpretation of ICC: &lt;0.50 poor; 0.50-0.75 moderate; 0.75-0.90 good (0.75 = minimal acceptable value for a reliable clinical measurement); &gt;0.90 excellent. Clinical trial information: 2018-000547-11. [Table: see text]

Prognostic Significance and Tumor Immune Microenvironment Heterogenicity of m5C RNA Methylation Regulators in Triple-Negative Breast Cancer.

PurposeThe m5C RNA methylation regulators are closely related to tumor proliferation, occurrence, and metastasis. This study aimed to investigate the gene expression, clinicopathological characteristics, and prognostic value of m5C regulators in triple-negative breast cancer (TNBC) and their correlation with the tumor immune microenvironment (TIM).MethodsThe TNBC data, Luminal BC data and HER2 positive BC data set were obtained from The Cancer Genome Atlas and Gene Expression Omnibus, and 11 m5C RNA methylation regulators were analyzed. Univariate Cox regression and the least absolute shrinkage and selection operator regression models were used to develop a prognostic risk signature. The UALCAN and cBioportal databases were used to analyze the gene characteristics and gene alteration frequency of prognosis-related m5C RNA methylation regulators. Gene set enrichment analysis was used to analyze cellular pathways enriched by prognostic factors. The Tumor Immune Single Cell Hub (TISCH) and Timer online databases were used to explore the relationship between prognosis-related genes and the TIM.ResultsMost of the 11 m5C RNA methylation regulators were differentially expressed in TNBC and normal samples. The prognostic risk signature showed good reliability and an independent prognostic value. Prognosis-related gene mutations were mainly amplified. Concurrently, the NOP2/Sun domain family member 2 (NSUN2) upregulation was closely related to spliceosome, RNA degradation, cell cycle signaling pathways, and RNA polymerase. Meanwhile, NSUN6 downregulation was related to extracellular matrix receptor interaction, metabolism, and cell adhesion. Analysis of the TISCH and Timer databases showed that prognosis-related genes affected the TIM, and the subtypes of immune-infiltrating cells differed between NSUN2 and NSUN6.ConclusionRegulatory factors of m5C RNA methylation can predict the clinical prognostic risk of TNBC patients and affect tumor development and the TIM. Thus, they have the potential to be a novel prognostic marker of TNBC, providing clues for understanding the RNA epigenetic modification of TNBC.

Current trends in the treatment of HR+/HER2+ breast cancer.

Treatment for HR+/HER2+ patients has been debated, as some tumors within this luminal HER2+ subtype behave like luminal A cancers, whereas others behavelike non-luminal HER2+ breast cancers. Recent research and clinical trials have revealed that a combination of hormone and targeted anti-HER2 approaches without chemotherapy provides long-term disease control for at least some HR+/HER2+ patients. Novel anti-HER2 therapies, including neratinib and trastuzumab emtansine, and new agents that are effective in HR+ cancers, including the next generation of oral selective estrogen receptor downregulators/degraders and CDK4/6 inhibitors such as palbociclib, are now being evaluated in combination. This review discusses current trials and results from previous studies that will provide the basis for current recommendations on how to treat newly diagnosed patients with HR+/HER2+ disease.