Non-luminal HER2 Research Articles

Oncological outcomes of stage I–II breast cancer treatment after subcutaneous/skin-sparing mastectomies with reconstruction

Aim. To study the recurrence of stage I–II breast cancer after subcutaneous/skin-sparing mastectomies with reconstruction with or without radiation therapy. Materials and methods. From 2013 to 2022, 984 patients diagnosed with breast cancer underwent 1020 subcutaneous/skin-sparing mastectomies with reconstruction at the P.A. Herzen Moscow State Medical Institute. Histological types are presented: cancer in situ – 7, invasive cancer without signs of specificity – 818, invasive lobular cancer – 105, combined cancer – 40, rare forms – 50. Subcutaneous mastectomy with reconstruction was performed in 617 (60.5 %), skin-sparing mastectomy in 403 (39.5 %) cases. Reconstruction with own tissues was performed in 5.7 %, expanders/implants in 94.3 % of patients. Patients with diagnosed mutations in the genes ВRCА1, 2, СНЕК2 amounted to 208 (21.1 %), while among patients with primary multiple synchronous cancer, the percentage with mutations was 25 %. Results. In the studied group of patients, recurrence of breast cancer was diagnosed in 40 (4.1 ± 0.1 %) cases, distant metastases – in 52 (5.3 ± 0.1 %) cases. The minimum time to relapse was 36 months, and the maximum was 108 months. In a single-factor analysis of the stage of the disease: at stage I, relapse was diagnosed in 25 (5.8 %) cases, at stage IIA (T2N0M0) – in 5 (2.0 %), at stage IIA (T1N1M0) – in 6 (4.2 %), at stage IIB T2N1M0 – in 4 (2.1 %) (p > 0.05). The recurrence in the group with radiation therapy was 2.5 ± 0.6 (odd ratio 0.98, 95 % confidential interval 1.52–3.48), without radiation therapy 5.1 % (odd ratio 2.13, 95 % confidential interval 0.92–5.18) regardless of the stage of breast cancer (t-criterion >2, p > 0.05). In our study, the recurrence of breast cancer at the edge of R1 was 6.8 ± 2.5 %, at R0 – 3 ± 0.6 % (p > 0.05). When analyzing age and risk of recurrence, we did not identify age dependence, up to 40 years the probability of recurrence is 4.3 ± 1 %, after 40 years – 3.3 ± 0.7 % (t-criterion 0.44, p > 0.05). The dependence of the degree of malignancy of the tumor node and the frequency of recurrence is as follows: G1 – 2. 3 ± 2.3 %, G2 – 3 ± 0.7 %, G3 – 3.9 ± 1 %, when compared G3 c G1 (t-criterion 0.52, p>0.05), when comparing G3 from G2 (t-criterion 0.49, p > 0.05). Recurrence of breast cancer with triple negative type was diagnosed in 2.5 ± 0.9 % relative to other molecular biological types (t-criterion 1.49, p > 0.05). We analyzed the dependence of relapse on the non-luminal and luminal HER2 positive types; the relapse was 5.4 ± 1.5 % (p > 0.05); the dependence on the level of Ki-67; at a level of 40 %, the probability of recurrence is 4 ± 0.8 %, at a level > 40 %, recurrence is 2 ± 0.8 % (t-criterion 1.77, p > 0.05). A statistically significant difference in our study was revealed, in addition to radiation therapy, during neoadjuvant polychemotherapy, so in the group with neoadjuvant polychemotherapy, the recurrence was 2 ± 0.8 %, without neoadjuvant polychemotherapy – 4.1 ± 0.7 % (t-criterion 2.16, р < 0.05). Conclusion. A link between breast cancer recurrence and morphological features (R1 resection margin, lymphovascular invasion, lymphatic tumor emboli, luminal and non-luminal HER2+ subtype, G3) and clinical characteristics (presence of mutations, location of a lesion in the gland, stages) was found. Further search for predictors of breast cancer recurrence after combination or integrated treatment is necessary.

MiRNAs in Signal Transduction of SMAD Proteins in Breast Cancer.

The aim of this study was to identify miRNAs that could potentially influence the activity of SMAD proteins involved in TGFβ signal transduction in five types of breast cancer in Polish women. Patients with five breast cancer subtypes were included in the study: luminal A (n = 130), luminal B HER2- (n = 100), luminal B HER2+ (n = 96), non-luminal HER2+ (n = 36), and TNBC (n = 43). During surgery, tumor tissue was removed along with a margin of healthy tissue (control). Molecular analysis included determination of the expression of genes related to SMAD protein signal transduction using mRNA microarrays and reverse transcription quantitative polymerase chain reaction (RT-qPCR). Protein expression was determined using an enzyme-linked immunosorbent assay (ELISA). The miRNA profiling was performed using miRNA microarrays and the miRDB database. SMAD3 and SMAD5 were overexpressed in all types of breast cancer, which could be related to the reduced expression of miR-145, and the findings for SMAD4 and miR-155 were similar. Additionally, the level of SMAD7 was reduced, which may be due to the low activity of miR-15b and miR21b. This study determined the gene expression profiles involved in SMAD protein signal transduction across five different types of breast cancer and identified the miRNAs potentially regulating their activity. Overexpression of SMAD3, SMAD4, and SMAD5 suggests excessive activation of the TGFβ pathway, potentially promoting tumor growth and development. Concurrently, a significant reduction in SMAD7 expression removes inhibitory control in the TGFβ pathway, a phenomenon that is particularly evident in more aggressive breast cancer types.

Clinicopathologic features of patients with breast cancer in a single tertiary hospital in the Philippines.

e23313 Background: Breast cancer incidence in the Philippines is among the highest in Asia - the WHO reported it to be as high as 33,079 in 2022. Data provided by the Philippine Cancer Society and Department of Health Rizal Cancer Registry in 2009 included 1,615 breast cancer patients and noted a significant increase in breast cancer incidence from the year 1980 to 2002 in 7 cities in Metro Manila. This retrospective study aims to describe and analyze clinicopathologic and treatment data of Filipino breast cancer patients in a tertiary hospital. This study represents the largest pooled data in the Philippines on breast cancer demographics. Methods: Patients diagnosed with invasive breast cancer in St. Luke’s Medical Center (SLMC) from 2009 to 2020 were included. Patients diagnosed with other breast histopathologic results [i.e. ductal and lobular carcinoma in situ without invasive component] and double primaries were excluded. The study was approved by the Ethics Review Committee (Reference No.: SL-19157). Results: A total of 5,462 breast cancer patients were included. Majority of the patients were late perimenopausal (50-59 yo, 30.06%), menopausal (60-69 yo, 23.03%), and premenopausal (below 44 yo, 19.28%,) at the time of diagnosis. Patients were diagnosed with stage II (N = 1,816, 47.24%), followed by stage I (N = 943, 24%), and stage III (N = 662, 17%). Sixty four percent (N = 1,498) were node negative while 46% (N = 1,300) were node positive. Among patients with de novo metastasis, 14.6% metastasized to the bone while visceral sites include chest wall (17.4%), lung (16.6%), liver (11.5%) and brain (7.45%). Luminal her2- (48.9%) was the most common clinical subtype followed by non-luminal her2+ (15.6%) and triple negative (6.7%). Definitive surgery was the mainstay of treatment – 94% (N = 4116) underwent modified radical mastectomy (MRM) while 5% (N = 223) underwent breast conserving surgery (BCS). Eight hundred patients (19%) received neoadjuvant treatment (hormonal and/or systemic chemotherapy) while 2,246 patients (54%) received adjuvant treatment. Total number of breast cancer patients who underwent adjuvant radiation was 1,399 (25.6%). Conclusions: Compared to middle-high income countries, data suggests that MRM is the preferred surgical technique over BCS. Majority of patients in the study are luminal her2-. However, only 54% received adjuvant treatment. Another observation is the low rate of neoadjuvant treatment by the study population. Further research on the risk factors or reasons for not receiving treatment as well as the outcomes of these patient cohorts is needed to shed light on these cancer care gaps.

Breast cancer in northern Peru: molecular subtypes and HER2 low.

This study aimed to understand the immunohistochemical profile of breast cancer and to identify the HER2 low subgroup in the northern macro-region of Peru. A cross-sectional study was conducted in 1176 patients from the Regional Institute of Neoplastic Diseases Northern Peru, from January 2016 to December 2023. We analyzed the data (age, histological type, grade and complementary results), with frequencies and percentages. The profile corresponded to: luminal B (45.6%); luminal A (24.7%); triple negative (18.2%); and HER2 positive non luminal (11.5%). In addition, 215 patients presented HER2 low (25.1% of those previously considered negative). This study provides evidence that the subtyping of breast cancer has changed, being luminal B the most frequent. It is essential to involve health policies to acquire targeted therapies considering HER2 low patients. Motivation for the study. Molecular classification of breast cancer allows the use of targeted treatments. Information on this profile in the northern macroregion of Peru is unknown. In addition, new therapies have appeared for a subgroup of patients. Main findings. In this study, the most frequent molecular subtypes were: luminal B, luminal A, triple negative and non-luminal HER2. Also, 18.3% of patients had low HER2 expression. Implications. Health policies should be aligned with scientific advances, to guarantee targeted therapies and to update the information in health manuals or protocols.

Radiomic Characteristics of Different T<sub>1</sub> Breast Cancer Biotypes

Background: Breast cancer (BC) occupies a leading position among my oncological diseases detected in women. Identification and search for predictors of malignant neoplasms using radiation and molecular genetic methods of research allows timely diagnosis and treatment, which improves the prognosis for breast cancer. Purpose: To identify a correlation between the molecular subtype of a breast cancer tumor at an early clinical stage and the patterns of the mammographic method. Methods: A prospective, single-center study of 363 patients diagnosed with breast cancer followed up during 2021. X-ray mammography in two projections, ultrasound-guided trephine biopsy for histological verification, and immunohistochemical (IHC) analysis to determine molecular subtypes were performed. Results: There were statistically significant differences in age between subtypes luminal A, luminal BHER2+ (p < 0.001) and triple negative (p = 0.037), luminal B, luminal BHER2+ (p = 0.001) and triple negative (p = 0.046), luminal BHER2+ and nonluminal HER2+ (p = 0.002), between nonluminal HER2+ and triple negative subtype (p = 0.034). When comparing the structure of radiological density, statistically significant differences were revealed between the subgroups luminal B, luminal BHER2+ (p = 0.010) and triple negative (p = 0.010), between luminal A and triple negative subtypes (p = 0.010). When comparing the leading mammographic symptom (p < 0.001), radiological contours of the formation (p < 0.001), the density of pathological changes (p < 0.001), the size, the newly detected pathological process (p < 0.001) statistically significant differences were also found in the subgroups. A division into groups according to the size of pathological changes within the biotypes was noted, where the aggressive phenotypes of the triple negative subtype (p = 0.001), non-luminal HER2+ (p = 0.02) and luminal B (p = 0.02), in contrast to luminal A, were manifested by a greater extent. the maximum linear size of the tumor. A symptom of nipple retraction (p = 0.048) was described, which was not characteristic of triple negative and non-luminal HER2 cancer. Conclusions: Visualization features of differences in the radiological manifestation of breast cancer of different biological subtypes up to 20 mm can be predictors of molecular subtypes. Pathological verification and IHC study remain a mandatory study, but it may be necessary to conduct an X-ray histological correlation before starting treatment and, if obvious discrepancies are detected, repeat the IHC analysis from the surgical material.

PDL1 Positivity Rate Between Triple-negative and Non-luminal Her2+ Cases

Background: Triple-negative breast cancer cases with no available targeted therapy and advanced cases of luminal and HER2+ that become resistant to available state-of-the-art treatments are priorities in cancer research. Immune checkpoint blockade, particularly PDL1/PD1 inhibition, is suggested as a potential option for these patients suffering from several other types of cancers, such as melanoma. However, the exact subpopulation of breast cancer patients that overexpress PDL1 is yet to be completely identified. Additionally, reports on the value of PDL1 as a biomarker for the prognosis of cancer and its correlation with clinicopathological features of malignancy are diverse. Method: In this study, we performed immunohistochemistry on 60 breast cancer, including 22 triple-negative and 38 HER2+ cases, and 20 paired lymph node samples. Results: PDL1 expression was present in 21. 6% (13/60) of breast cancer samples. PDL1 expression is significantly associated with ER/PR negativity and the grade of the tumor. The association between PDL1 positivity and recurrence and the overall survival of patients was not significant. Conclusion: PDL1 expression is similar between triple-negative and non-luminal HER2+ cases, thus some of the advanced non-luminal HER2+ cases might be benefitted from immune checkpoint blockade.

Metaplastic Breast Cancer: Mesenchymal Subtype Has Worse Survival Outcomes

Background: Metaplastic breast carcinoma (MBC) is a rare type of breast cancer that accounts for 0.2–1% of all breast cancers. To date, there are only few institutional studies comparing survival rates between different subtypes. In this retrospective cohort study, we aim to evaluate factors effecting survival rates of different subtypes of MBC. Methods: This retrospective cohort study observed 118 nonmetastatic MBC patient records extracted from 15,244 breast cancer cases between December 2000 and December 2020. In order to analyze factors effecting survival rates of mesenchymal subtype of MBC, all cases are classified as mesenchymal (n = 45) and other (n = 48). Twenty-five cases could not be sub-classified due to the missing data. Univariate and multivariate logistic regression analyses were performed to define factors associated with survival rates. Results: Of the 15,244 cases, 118 (0.8%) were nonmetastatic MBC. 105 were triple negative and 12 were nonluminal HER2. There was no significant difference between mesenchymal and other subgroups for age, median tumor size, AJCC staging, and type of surgery. Of the five local recurrences with known subgroup, four of them had mesenchymal subtype. It is demonstrated that mesenchymal subtype was significantly associated with worse 5-year disease-free survival and disease-specific survival (HR: 2.35 [1.01–5.48], p = 0.049, and HR: 3.16 [1.06–9.47], p = 0.040 with 95% CI, respectively). Conclusion: This study is one of the few studies presenting the survival outcomes of subtypes of MBCs. Nonetheless, it is the only study demonstrating that mesenchymal subtype had worse survival outcomes. Further studies are needed to determine the outcome of different subtypes of MBCs.

Abstract P1-01-07: Factors predicting a lower likelihood of residual nodal disease in clinically-node positive patients undergoing sentinel node surgery after neoadjuvant chemotherapy for breast cancer

Abstract Background: Residual nodal disease at the completion axillary lymph node dissection (ALND) has been reported in over 60% in patients with a positive sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NAC). This study aimed to explore whether any clinical or histopathological characteristics of patients may be associated with a lower likelihood of having non-SLN metastasis at ALND. Methods: Between January 2004 to January 2021, 459 patients with cT1-4/N1-3 underwent ALND due to a positive SLNB after NAC. Demographic, clinical and histopathological characteristics of patients were analyzed to predict the non-SLN metastasis at ALND. Sentinel lymph node ratio was defined as the ratio of the number of positive SLN to the total excised SLNs. Results: Median age was 47 (21-84). Of those, the majority of the patients had cT1-2 (67.8%) and cN1 disease (78.1%), whereas 76.5% of tumors were invasive ductal carcinoma. The frequency of non-SLN metastases according to the tumor subtypes were 59.5% in luminal A, 73.8% in HER2(-) luminal B, 60.3% in HER2(+) luminal B, 66.7% in non-luminal HER2(+), and 66.7% in triple negative breast carcinoma. Of those with removal more than 2 SLNs, having 1 positive SLN, or breast pathologic complete response, or cT1-2 disease , or a SLN ratio <50% or low volume metastatic disease including isolated tumor cell (ITC)/micrometastasis were statistically less likely found to have a non-SLN metastasis (p<0.05). Factors associated with a non-SLN involvement less than 40% were a SLN ratio <50% (39.2%) and low volume metastatic disease (36.4%). Multivariate logistic regression analysis revealed a decreased likelihood for non-SLN metastasis at ALND for patients with cT1-2 (OR= 0.45; 95% CI: 0.25-0.82; p=0.009), ITC and micrometastasis (OR=0.24; 95% CI: 0.09-0.65; p=0.006), and a SLN-ratio <50% ((OR=0.15; 95% CI: 0.08-0.26; p<0.001). A subgroup of patients with cT1-2/N1 having a SLN ratio <50% or ITC/micrometastasis were found to have 25.9% and 28.6% non-SLN positivity at ALND, respectively. Conclusions: In patients with a positive SLN after NAC, the likelihood of having residual disease at ALND was high across all tumor subtypes and clinical patient and tumor characteristics. However, the residual nodal disease rate was found to be lower than 30% in carefully selected patient subgroups with cT1-2/N1 along with ITC/micrometastasis or a SLN ratio <50% (Table 1) . These results suggest omission of ALND could be considered in meticulously selected patients with cT1-2 and low volume metastatic disease as long as axillary radiation and effective systemic treatment provided Table 1. Factors associated with non-SLN metastasis at ALND FactorsOR(95%CI)p-valuecT0.009*1&20.45(0.25-0.82)3&4Reference (1)SLN Status0.006*ITC and micrometastasis0.24(0.09-0.65)MacrometastasisReference (1)SLN-Ratio (%)<0.001*<50%Reference(1)≥50%0.15(0.08-0.26)*:p<0.05, Logistic regression(enter method), OR:Odds Ratio; Dependent variable:Non-SLN positivity Citation Format: Neslihan Cabioglu, Hasan Karanlık, Abdullah Igci, Mahmut Muslumanoglu, Mustafa Tukenmez, Selman Emiroglu, Enver Ozkurt, Semen Onder, Pinar Saip, Yesim Eralp, Adnan Aydiner, Ekrem Yavuz, Vahit Ozmen. Factors predicting a lower likelihood of residual nodal disease in clinically-node positive patients undergoing sentinel node surgery after neoadjuvant chemotherapy for breast cancer [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 P1-01-07.

Abstract PD7-09: Safety of conservative surgery with accelerated partial breast re-irradiation for isolated ipsilateral breast cancer recurrence regardless of immunohistochemical subtype. A multicentric prospective study

Abstract Background. The standard of care for patients (pts) with an ipsilateral breast tumour recurrence (IBTR) after breast conserving therapy (BCT) is a salvage mastectomy. However there is no solid data providing a clear advantage of radical surgery for IBTR in terms of the outcome for patients with isolated local recurrence after BCT. Nevertheless, there is a growing interest in the feasibility of repeating BCT for these patients (pts). We analyzed the oncological outcomes of repeated breast-conserving therapy (rBCT) related to the immunohistochemical subtype. Materials and methods. Between 2014 and 2020, 35 pts were selected for a 2nd BCT, a new lumpectomy with accelerated partial breast re-irradiation (APBrI), and prospectively followed in three university hospitals in Barcelona. Inclusion criteria were pts older than 50y with a late (> 48m from primary treatment) isolated IBTR less than 2cm, without having primary major radiotherapy toxicity. Oncological outcomes were analyzed. Results. At IBTR, median age was 65y and median time to ITBR was 154m. Patients characteristics are shown in table 1. Tumor’s recurrence was DCIS in 5 pts (14.3%) and invasive carcinoma in 30 pts (85.7%), where Luminal A in 10 pts (33.3%), Luminal B-HER2 negative in 12 pts (40%), Luminal B-HER2 positive in 2 (6.7%), non-Luminal HER2 positive in 3 (10%) and triple negative in 3 (10%). With a median follow-up of 37 months, there were 4 relapses (11.4%), one was a 2nd IBTR (2.85%) after in-situ IBTR, and 3 were metastatic recurrences (8.6%), two after invasive and one after in-situ IBTR. Both metastatic progressions after invasive IBTR, were hormone receptor positive and HER2 negative (Luminal B). There were 2 deaths not related with breast cancer. The 2nd IBTR rate was 2.85%. Five-year regional-free survival, metastasis-free survival, and overall survival was 82.4% (95% IC 52.6 - 94.4 %), %, 84.6% (95% IC 51 - 96 %) and 93.3% (95% IC 61.2 - 99%), respectively. Conclusion. Conservative treatment with breast conserving surgery and APBrI for isolated IBTR after BCT seems like a feasible technique as an alternative to mastectomy in selected patients. Second local recurrences and overall survival are similar to the rates described for salvage mastectomy for isolated ipsilateral breast tumour recurrence. In this cohort of patients, the immunohistochemical subtype tumors with poor prognosis (HER2 positive and triple negative) did not show increase in the local recurrence rate. Table 1.Patients Characteristicsn%Histology TypeIDC2777.1ILC0DCIS514.3Others38.6Differentiation gradeWell differentiated1028.6Moderately differentiated1851.4Poorly differentiated720Estrogen-receptor statusPositive2880Negative720Progesteron-receptor statusPositive1645.7Negative1748.6Unknown25.7HER2 statusOver-expressed617.1Non-over-expressed2674.3Unknown38.6Ki67< 20 %1748.6> 20 %1337.2Unknown514.3IHC subtypeLuminal A1033.3Luminal B1240Luminal B-HER2 positive26.7Non-luminal HER2 positive310Triple negative310IBTR locatedSame quadrant1748.6Different quadrant1645.7Unknwon25.7APBrI3D-CRT927.3IORT26.1IMRT2266.7 Citation Format: Martin Espinosa-Bravo, Victoria Reyes Lopez, Clara Morales Comas, Joaquín Rivero Déniz, Javier de La Torre Fernández de Vega, Irene Vives Roselló, Christian Sisó Raber, Manuel Altabas Gonzalez, Alexandra Giraldo Marin, Inma Alonso, Nuria Argudo, Pau Nicolau, Manel Algara, Xavier Sanz, Xavier Caparrós, Gabriela Oses, Jordi Saez, María Vernet-Tomas, Meritxell Mollà. Safety of conservative surgery with accelerated partial breast re-irradiation for isolated ipsilateral breast cancer recurrence regardless of immunohistochemical subtype. A multicentric prospective study [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 PD7-09.

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.

Features of response to modern neoadjuvant chemotherapy with dual anti-HER2 blockade (trastuzumab and pertuzumab) in the patients with HER2-positive breast cancer stage II–III

Background. Neoadjuvant chemotherapy (NACT) with dual anti-HER2 blockade has become a priority in the treatment of patients with HER2+ breast cancer (BC) stages IIIII. However, the question of the accordance of various systems for assessing tumor response to NACT, as well as identifying predictor factors for achieving a complete pathomorphological response (pCR) in HER2+ BC remains open.
 Aim. To assess the accordance of various systems for assessing tumor response to neoadjuvant chemotherapy (NACT) in patients with HER2+ BC and to identify predictor factors for achieving pCR and residual cancer burden.
 Materials and methods. The study included 49 women with HER2+ BC stage IIIII, who underwent NACT with anti-HER2 blockade, followed by surgical treatment and morphological analysis of the results. The median age of the patients was 47 years; 91.8% had tumor size T2, N+ status 71.4%; tumor grade G3 73.5%, luminal and non-luminal HER2+ subtype 44.9 and 55.1% of patients, respectively. Ki6730% was observed in 93.9% of cases, the level of TILs in the tumor was 10%, 1020% and 20% in 38.1, 9.5 and 52.4% of cases, respectively. The patients received combinations of anthracyclines and taxanes or the anthracycline-free regimen of docetaxel + carboplatin; 87.8% of patients received a dual blockade of trastuzumab + pertuzumab, and 12.2% trastuzumab. After the end of NACT, all patients underwent a radical surgery (mastectomy or breast-conserving) with an assessment of the pathomorphological response, the pathomorphological stage of ypTN, and the residual cancer burden according to the RCB system.
 Results. The rate of complete pathomorphological response (tpCR/RCB-0/ypT0N0) in HER2+ BC was 61.2%; significant predictors of achieving tpCR were only 3 factors: primary operable BC stages (T13N01) the rate of tpCR was 71.4%, the level of TILs20% the proportion of tpCR reached 95.5%, and the dual anti-HER2 therapy (trastuzumab + pertuzumab) tpCR was 65.1%. Residual tumor was presented by classes RCB-I, RCB-II, RCB-III in 10.2, 24.5, 4.1%. The RCB-I class included of patients with a residual tumor less than 1.0 cm in the absence of regional lymph node involvement (80% of cases); class RCB-II was represented by the presence of a residual tumor less than 2.0 cm in combination with the absence or presence of residual metastases in 13 lymph nodes (83.4%), and class RCB-III was presented the residual tumors 2.0 cm and N12 status in 100% of cases (p0.0001).
 Conclusion. Modern NACT with dual anti-HER2 blockade (trastuzumab + pertuzumab) are highly effective the rate of tpCR is 61.2%, and in the presence of high TILs20% reaches 95.5%. Residual tumor in most cases was presented by class RCB-I or RCB-II, only 4% of patients had massive residual tumor load (class RCB-III).

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.

Association Between Metabolic Syndrome and Immunohistochemical Profile at Breast Cancer Diagnosis in Postmenopausal Women

BackgroundThe aim of this study was to evaluate the association between metabolic syndrome (MetS) and the immunohistochemical profile of breast cancer (BC) in postmenopausal women. MethodsThis cross-sectional cohort study included 189 women, aged 45 to 75years and amenorrhea >12 months, with newly diagnosed BC and no previous cancer treatment. Clinical, anthropometric and biochemical data were collected, as well as data on BC hormone status (estrogen receptor, ER; progesterone receptor, PR; human epidermal growth factor receptor-2, HER-2), and epithelial proliferative activity (Ki-67). Tumors were divided into 5 subtypes:luminal A, luminal B HER-2 negative, luminal B HER-2 positive, non-luminal HER-2, and triple negative. Women with three or more of the following criteria were diagnosed with MetS: waist circumference ≥88cm; triglycerides ≥150mg/dL; HDL-cholesterol <50mg/dL; blood pressure ≥130/85mmHg; glucose ≥100mg/dL. ResultsSixty-three (33.3%) of the 189 patients had MetS at the time of diagnosis. Women with MetS had a higher frequency of tumors ≤ 2cm than women without MetS (49.2% vs. 31.8%) (P = .038). There were no differences in histological grade, staging, or axillary lymph node metastasis (P > .05). The proportion of PR-positive (P = .006), HER-2-negative (P = .034), and luminal B HER-2-negative (P = .038) tumors was higher among patients with MetS compared to women without MetS (79.4% vs. 61.8%, 89.9% vs. 78.6% and 44.5% vs. 27.8%, respectively). Multivariate analysis adjusted for age, time since menopause and BMI showed a higher risk for luminal B HER-2-negative tumors among women with MetS (OR 2.00, 95% CI 1.03-3.89), obese patients (OR 2.03, 95% CI 1.06-3.90), and women with abdominal obesity (OR 1.96, 95% CI 1.01-4.03). ConclusionIn postmenopausal women with newly diagnosed BC, the presence of MetS was associated with smaller tumor size, PR-positive and HER-2-negative status, and the luminal B tumor subtype.

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.

Changes of immunohistochemical biomarkers before and after neoadjuvant chemotherapy in breast cancer and their prognosis

Objective: To investigate changes in the expression of immunohistochemical (IHC) markers and factors associated with the effect of chemotherapy before and after neoadjuvant chemotherapy (NAC). Methods: A retrospective study included 200 breast cancer patients treated with NAC between January 2016 and December 2018. We analyzed the changes in the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and Ki-67 in pre- and post-treated samples and the predictive factors of NAC. Results: Among the 200 cases, 16 cases were luminal A, 108 cases were luminal B, 36 cases were HER2+subtype, and 40 cases were basal-like. Twenty-five patients (12.50%) achieved pathological complete remission (PCR).There were significant differences in PR and Ki-67 before and after NAC but there were no differences in ER and HER2.In univariate analysis, factors associated with PCR were tumor less than 5 cm(P=0.009), non-luminal breast cancer (P=0.001), ER negative(P=0.001), PR negative (P=0.029) and HER2 positive(P=0.001). Tumor less than 5 cm [P=0.020, OR=2.581, 95%CI (1.207, 5.753)], ER negative [P=0.011, OR=2.264, 95%CI (1.207, 4.248)] and HER2 positive[P=0.007, OR=2.412, 95%CI (1.275, 4.561)] remained predictive variables in multivariate analysis after correction for the other variables. Conclusions: The expression of Ki-67 decreases after NAC. Negative PR and ER and positive HER2 status are related to the efficacy of pCR for breast cancer, and have guiding significance for the prognosis evaluation of NAC.

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.

Abstract PS7-76: Association between metabolic syndrome and immunohistochemical profile at breast cancer diagnosis in postmenopausal women

Abstract Objective: To evaluate the association between metabolic syndrome (MetS) and the immunohistochemical profile of breast cancer (BC) in postmenopausal women.Methods: This cross-sectional cohort study included 189 women, aged 45-75 years and amenorrhea &amp;gt; 12 months, with newly diagnosed BC and no previous cancer treatment. Clinical, anthropometric and biochemical (total cholesterol, HDL, LDL, triglycerides, and glucose) data were collected, as well as data on BC (histopathology, grade, tumor stage, lymph node metastasis hormone status (estrogen receptor, ER; progesterone receptor, PR; human epidermal growth factor receptor 2, HER-2), and epithelial proliferative activity (Ki-67). Tumors were divided into five subtypes: luminal A, luminal B HER-2 negative, luminal B HER-2 positive, non-luminal HER-2, and triple negative. Women with three or more of the following criteria were diagnosed with MetS: waist circumference ≥ 88 cm; triglycerides ≥ 150 mg/dL; HDL-cholesterol &amp;lt; 50 mg/dL; blood pressure ≥ 130/85 mmHg; glucose ≥ 100 mg/dL. The Student t-test, gamma distribution (asymmetric variables), chi-square test, and logistic regression (odds ratio, OR) were used for statistical analysis.Results: Sixty-three (33.3%) of the 189 patients had MetS at the time of diagnosis. The mean age, time since menopause and BMI were 59.0 ± 10.6 years, 11.4 ± 9.6 years and 28.5 ± 5.5 kg/m2, respectively, without difference between women with and without MetS (control). Women with MetS had a higher frequency of tumors ≤ 2 cm than women without MetS (49.2% vs 31.8%) (p=0.038). There were no differences in histological grade, staging, or axillary lymph node metastasis (p&amp;gt;0.05). The proportion of PR-positive (p=0.006), HER-2-negative (p=0.034), and luminal B HER-2-negative tumors was higher among patients with MetS (p=0.038) compared to women without MetS (79.4% vs 61.8%, 89.9% vs 78.6% and 44.5% vs 27.8%, respectively). Multivariate analysis adjusted for age, time at menopause and BMI showed a higher risk for luminal B HER-2-negative tumors among women with MetS (OR 2.00, 95% CI 1.03-3.89), obese patients (OR 2.03, 95% CI 1.06-3.90), and women with abdominal obesity (OR 1.96, 95% CI 1.01-4.03). The other BC subtypes were not associated with MetS or its components.Conclusion: In postmenopausal women with newly diagnosed BC, the presence of MetS was associated with a more favorable immunohistochemical profile of BC, such as a smaller tumor size, PR-positive and HER-2-negative status, and the luminal B tumor subtype. Citation Format: Andre Hideo Motoki, Daniel de AraujoBrito Buttros, Ana LuisaCamolezi Gaspar, Eduardo Carvalho Pessoa, Benedito de Sousa Almeida Filho, Jorge Nahas Neto, Heloisa de Luca Vespoli, Eliana AguiarPetri Nahas. Association between metabolic syndrome and immunohistochemical profile at breast cancer diagnosis in postmenopausal women [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-76.

Characteristics and survival of de novo and recurrent metastatic breast cancer in New Zealand

We aim to examine the characteristics and survival of patients with de novo metastatic breast cancer (dnMBC) and recurrent metastatic breast cancer (rMBC) in New Zealand. This study included women diagnosed with dnMBC and women who developed rMBC between 2010 and 2017. The Kaplan-Meier method was used to examine cancer-specific survival. Cox proportional hazards regression was used to estimate the adjusted hazard ratio (HR) of cancer-specific mortality by ethnicity, age, year of diagnosis, socioeconomic deprivation, site of metastases, number of metastatic sites, biomarker subtype and MBC subgroup. We included 2177 MBC patients (667 dnMBC and 1510 rMBC). The median survival of dn MBC patients was 26months compared to 18months for rMBC. There were no differences in breast-cancer specific mortality by ethnicity or socioeconomic deprivation. The adjusted HR for patients with visceral metastases compared to patients with non-visceral metastases was 1.41, and the adjusted HR for triple negative disease compared to Luminal A disease was 2.24. Compared to dnMBC, the adjusted HRs for rMBC patients with a metastatic-free interval of < 2years, 2-4years, 5-7year and 8 + years were 1.81, 1.47, 1.08 and 0.82, respectively. The survival for patients with MBC in New Zealand is very similar to other developed countries. Patients with dnMBC had a much better prognosis than those with recurrent disease. Patients with triple negative disease or non-luminal HER2 positive disease had the worst prognosis. The prognosis for patient with rMBC improved the longer the time from diagnosis to the development of metastases.

Abstract P2-05-03: Integrated analysis of mismatch repair, PD-L1, and immune microenvironment status in pregnancy-associated breast cancers

Abstract Introduction: Breast cancer (BC) occurring during gestation or lactation is rare, yet highly challenging under both biological and clinical standpoints. This condition, referred to as pregnancy-associated (PA) BC (PABC), shows enrichment in mismatch repair (MMR) deficiency mutational signature, higher expression of immune-checkpoint genes, and less tumor-infiltrating lymphocytes (TILs) compared to non-PA BCs. Despite these insights, no comprehensive data on MMR protein status, immune checkpoints, and immune microenvironment are currently available for these tumors. The aim of this study was to characterize the MMR status and immunologic milieu of PABC. Methods: Among a multi-Institutional database comprising 142 PABCs, we conducted a comparative analysis of a cohort of PABC (n=29) and a control group of age-matched non-PA BCs (n=74). Distinct areas of each tumor and the corresponding normal breast tissue were incorporated into a tissue microarray (4-6 cores per case, mean 4.5). For all cases, both stromal and intratumoral TILs were quantified according to the International TILs Working Group recommendations. Representative slides were subjected to immunohistochemical (IHC) analysis of the MMR proteins (i.e. MLH1, MSH2, MSH6, and PMS2), programmed death-ligand 1 (PD-L1), CD4, and CD8. Cases were classified as MMR-proficient (pMMR), MMR-deficient (dMMR), and, when the protein was expressed only in a part of the tumor, MMR-heterogeneous (hMMR). PD-L1 expression was evaluated separately in the tumor cells, stromal TILs, and intratumoral TILs. Finally, the relative proportion of CD4+ and CD8+ cells was assessed in both stromal and intratumoral TILs. Results: The study group included 4 (14%) Luminal A, 10 (35%) Luminal B, 4 (14%) non-luminal HER2+, and 11 (37%) triple-negative (TN) PABCs. Taken together, both the dMMR and hMMR status were more common in PABCs than in non-PA BC (n=3/29, 19% vs. n=6/74, 8% and n=7/29, 24% vs. 14/74, 19%, respectively). Specifically, dMMR was seen in Luminal A (n=2, 50%) and in TN (n=1, 9%) PABCs. Conversely, in non-PA BCs, all Luminal A (n=15, 100%) were pMMR, while 5/45(11%) Luminal B and 1/13 (7%) TNBC were dMMR. Despite no differences were observed in intratumoral TILs, PABCs showed significantly higher levels of stromal TILs (p=0.01). Compared to the control group, PD-L1 expression in PABCs was significantly higher in the tumor cells and in stromal TILs (p&amp;lt;0.01) but not in intratumoral TILs. Hence, 9 (31%) PABCs were PD-L1+, with tumor proportion scores (TPS) ranging from 2 to 10 (mean 5), while only 4 (5%) non-PA BCs were PD-L1+ (TPS 2-20, mean 8)(p=0.01). The expression of PD-L1 in stromal TILs was higher in PABCs (n=9, 31%) than in the controls (n=19, 26%)(p=0.005). In Luminal tumors, both the CD4+ and CD8+ populations were more represented than in non-PA BCs (p=0.01), while in TNBC only the relative proportion of CD4+ cells was significantly higher (p=0.02). Discussion: This study is the first to investigate the immune response alongside the MMR status by IHC in PABCs. Our findings broaden the understanding of the immunobiology underpinning PABC, suggesting that in these tumors i) MMR protein alterations occur at higher frequency than in non-PA BCs; ii) the tumor cells and tumor microenvironment may be capable to suppress the adaptive arm of immune system through the expression of PD-L1; and iii) lymphocytes located at the periphery rather than those inside of the tumor are likely to be implicated in the immune modulation. Conclusion: The MMR system and immune microenvironment may play a consistent role in the natural history of PABCs. An intimate knowledge of the multifaceted interplay between tumor and tumor immune microenvironment is likely to unveil clinically relevant mechanisms that may have a positive net health impact for women with BC during gestation or lactation. Citation Format: Nicola Fusco, Elena Guerini-Rocco, Barbara Buonomo, Roberto Croci, Caterina Fumagalli, Gianluca Lopez, Giorgio A Croci, Letterio Runza, Elham Sajjadi, Concetta Blundo, Luca Despini, Massimo Giroda, Viviana E Galimberti, Paolo Veronesi, Massimo Barberis, Stefano Ferrero, Giovanna Scarfone, Silvano Bosari, Giuseppe Viale, Fedro Peccatori. Integrated analysis of mismatch repair, PD-L1, and immune microenvironment status in pregnancy-associated breast cancers [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-05-03.

INCREASED SERUM LEVEL OF PEPTIDYL ARGININE DEIMINASE TYPE 4 IN VARIOUS MOLECULAR BIOLOGICAL SUBTYPES OF BREAST CANCER

Level of enzyme peptidyl arginine deiminase type 4 (PAD-4) was determined in serum samples collected from 98 females with primary breast cancer within January, 2017 – April, 2018 divided into 5 groups according to immunohistochemistry data: group 1 – luminal A cancer, 2 – luminal B Her-2 negative, 3 – luminal B Her-2 positive, 4 – non-luminal Her-2 positive, 5 – triple negative cancer. Samples were collected prior to the onset of any anti-cancer treatment, and in 41 cases – 15-24 days after performing radical surgery. Control samples were obtained from 20 healthy females. Serum PAD-4 level was measured with Human PAD-4 ELISA Kit (Wuhan Fine Biotech Co., Ltd, China) on automatic analyzer ADALTIS Personal LAB (Adaltis S.r.l., Italy). Statistical analysis was performed by using software IBM SPSS Statistics 19. Mean serum PAD-4 level before treatment was 9.0 ng/ml that did not change after surgery. However, mean PAD-4 level for healthy females was 1.5 ng/ml (0.0-2.0) ng/ml that significantly differed from cancer group (Mann–Whitney U test, U = 38.500, p0.001). in contrast PAD-4 level in various cancer groups was: group 1 – 11.05 ng/ml, group 2 – 11.9 ng/ml, group 3 – 10.8 ng/ml, group 4 – 7.99 ng/ml, group 5 – 9.9 ng/ml. Thus, level of serum PAD-4 was higher in groups with more favorable luminal cancer, but further research is needed to make definitive conclusions.