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Purpose: We compared the mutational profile of second breast cancers (SBC) following first ipislateral hormone receptor–positive breast cancers of patient-matched tumors to distinguish new primaries from true recurrences. Experimental Design: Targeted next-generation sequencing using the Oncomine Tumor Mutation Load Assay. Variants were filtered according to their allele frequency ≥ 5%, read count ≥ 5X, and genomic effect and annotation. Whole genome comparative genomic hybridization array (CGH) was also performed to evaluate clonality. Results: Among the 131 eligible patients, 96 paired first breast cancer (FBC) and SBC were successfully sequenced and analyzed. Unshared variants specific to the FBC and SBC were identified in 71.9% and 61.5%, respectively. Paired samples exhibited similar frequency of gene variants, median number of variants per sample, and variant allele frequency of the reported variants except for GATA3. Among the 30 most frequent gene alterations, ARIDIA, NSD2, and SETD2 had statistically significant discordance rates in paired samples. Seventeen paired samples (17.7%) exhibited common variants and were considered true recurrences; these patients had a trend for less favorable survival outcomes. Among the 8 patients with available tissue for CGH analysis and considered new primaries by comparison of the mutation profiles, 4 patients had clonally related tumors. Conclusions: Patient-matched FBC and SBC analysis revealed that only a minority of patients exhibited common gene variants between the first and second tumor. Further analysis using larger cohorts, preferably using single-cell analyses to account for clonality, might better select patients with true recurrences and thereby better inform the decision-making process.

Atezolizumab in combination with nab-paclitaxel has been introduced for the treatment of locally advanced or recurrent triple negative breast cancer (TNBC). Patient selection relies on the use of immunohistochemistry using a specific monoclonal PD-L1 antibody (clone SP142) in a tightly controlled companion diagnostic test (CDx) with a defined interpretative algorithm. Currently there are no standardized recommendations for selecting the optimal tissue to be tested and there is limited data to support decision making, raising the possibility that tissue selection may bias test results. We compared PD-L1 SP142 assessment in a collection of 73 TNBC cases with matched core biopsies and excision samples. There was good correlation between PD-L1-positive core biopsy and subsequent excision, but we found considerable discrepancy between PD-L1 negative core biopsy and matched excision, with a third of cases found negative on core biopsies converting to positive upon examination of the excision tissue. In view of these findings, we developed a workflow for the clinical testing of TNBC for PD-L1 and implemented it in a central referral laboratory. We present audit data from the clinical PD-L1 testing relating to 2 years of activities, indicating that implementation of this workflow results in positivity rates in our population of TNBC similar to those of IMpassion130 clinical trial. We also developed an online atlas with a precise numerical annotation to aid pathologists in the interpretation of PD-L1 scoring in TNBC.

Supplementary Table 3 from Exon-Based Clustering of Murine Breast Tumor Transcriptomes Reveals Alternative Exons Whose Expression Is Associated with Metastasis

Supplementary Figure Legends 1-11, Table Legends 1-3, Methods from Exon-Based Clustering of Murine Breast Tumor Transcriptomes Reveals Alternative Exons Whose Expression Is Associated with Metastasis

Altered expression of microRNAs (miRNA), an abundant class of small nonprotein-coding RNAs that mostly function as negative regulators of protein-coding gene expression, is common in cancer. Here, we analyze the regulation of miRNA expression in response to estrogen, a steroid hormone that is involved in the development and progression of breast carcinomas and that is acting via the estrogen receptors (ER) transcription factors. We set out to thoroughly describe miRNA expression, by using miRNA microarrays and real-time reverse transcription-PCR (RT-PCR) experiments, in various breast tumor cell lines in which estrogen signaling has been induced by 17β-estradiol (E2). We show that the expression of a broad set of miRNAs decreases following E2 treatment in an ER-dependent manner. We further show that enforced expression of several of the repressed miRNAs reduces E2-dependent cell growth, thus linking expression of specific miRNAs with estrogen-dependent cellular response. In addition, a transcriptome analysis revealed that the E2-repressed miR-26a and miR-181a regulate many genes associated with cell growth and proliferation, including the progesterone receptor gene, a key actor in estrogen signaling. Strikingly, miRNA expression is also regulated in breast cancers of women who had received antiestrogen neoadjuvant therapy. Overall, our data indicate that the extensive alterations in miRNA regulation upon estrogen signaling pathway play a key role in estrogen-dependent functions and highlight the utility of considering miRNA expression in the understanding of antiestrogen resistance of breast cancer. [Cancer Res 2009;69(21):8332–40]

Supplementary Figures 1-7, Tables 1-9 from Widespread Estrogen-Dependent Repression of microRNAs Involved in Breast Tumor Cell Growth

Supplementary Table 2 from Widespread Estrogen-Dependent Repression of microRNAs Involved in Breast Tumor Cell Growth

Supplementary Figure Legends 1-7, Methods from Widespread Estrogen-Dependent Repression of microRNAs Involved in Breast Tumor Cell Growth

Supplementary Tables 1-2, Figures 1-2, Material and Methods from Formation of the eIF4F Translation–Initiation Complex Determines Sensitivity to Anticancer Drugs Targeting the EGFR and HER2 Receptors

Supplementary Figure 3 from PTPL1/PTPN13 Regulates Breast Cancer Cell Aggressiveness through Direct Inactivation of Src Kinase

Supplementary Figure 1 from PTPL1/PTPN13 Regulates Breast Cancer Cell Aggressiveness through Direct Inactivation of Src Kinase

Supplementary Table 1 from Widespread Estrogen-Dependent Repression of microRNAs Involved in Breast Tumor Cell Growth

Supplementary Figures 1-11 from Exon-Based Clustering of Murine Breast Tumor Transcriptomes Reveals Alternative Exons Whose Expression Is Associated with Metastasis

Supplementary Table 4 from Widespread Estrogen-Dependent Repression of microRNAs Involved in Breast Tumor Cell Growth

Supplementary Table 2 from Exon-Based Clustering of Murine Breast Tumor Transcriptomes Reveals Alternative Exons Whose Expression Is Associated with Metastasis

Supplementary Figure 4 from PTPL1/PTPN13 Regulates Breast Cancer Cell Aggressiveness through Direct Inactivation of Src Kinase

Supplementary Table 3 from Widespread Estrogen-Dependent Repression of microRNAs Involved in Breast Tumor Cell Growth

Supplementary Figure 2 from PTPL1/PTPN13 Regulates Breast Cancer Cell Aggressiveness through Direct Inactivation of Src Kinase

Supplementary Table 5 from Widespread Estrogen-Dependent Repression of microRNAs Involved in Breast Tumor Cell Growth

The protein tyrosine phosphatase PTPL1/PTPN13, the activity of which is decreased through allelic loss, promoter methylation, or somatic mutations in some tumors, has been proposed as a tumor suppressor gene. Moreover, our recent clinical study identified PTPL1 expression level as an independent prognostic indicator of a favorable outcome for patients with breast cancer. However, how PTPL1 can affect tumor aggressiveness has not been characterized. Here, we first show that PTPL1 expression, assessed by immunohistochemistry, is decreased in breast cancer and metastasis specimens compared with nonmalignant tissues. Second, to evaluate whether PTPL1 plays a critical role in breast cancer progression, RNA interference experiments were performed in poorly tumorigenic MCF-7 breast cancer cells. PTPL1 inhibition drastically increased tumor growth in athymic mice and also enhanced several parameters associated with tumor progression, including cell proliferation on extracellular matrix components and cell invasion. Furthermore, the inhibition of Src kinase expression drastically blocked the effects of PTPL1 silencing on cell growth. In PTPL1 knockdown cells, the phosphorylation of Src on tyrosine 419 is increased, leading to the activation of its downstream substrates Fak and p130cas. Finally, substrate-trapping experiments revealed that Src tyrosine 419 is a direct target of the phosphatase. Thus, by identification of PTPL1 as the first phosphatase able to inhibit Src through direct dephosphorylation in intact cells, we presently describe a new mechanism by which PTPL1 inhibits breast tumor aggressiveness. Cancer Res; 70(12); 5116–26. ©2010 AACR.

Supplementary Table 1 from Exon-Based Clustering of Murine Breast Tumor Transcriptomes Reveals Alternative Exons Whose Expression Is Associated with Metastasis

Supplementary Figure Legends 1-4 from PTPL1/PTPN13 Regulates Breast Cancer Cell Aggressiveness through Direct Inactivation of Src Kinase

The importance of integrating biomarkers into the TNM staging has been emphasized in the 8th Edition of the American Joint Committee on Cancer (AJCC) Staging system. In a pooled analysis of 2148 TNBC-patients in the adjuvant setting, TILs are found to strongly up and downstage traditional pathological-staging in the Pathological and Clinical Prognostic Stage Groups from the AJJC 8th edition Cancer Staging System. This suggest that clinical and research studies on TNBC should take TILs into account in addition to stage, as for example patients with stage II TNBC and high TILs have a better outcome than patients with stage I and low TILs.

Trastuzumab deruxtecan (T-DXd) is an anti-HER2 (human epidermal growth factor receptor 2) antibody-drug conjugate which has previously shown efficacy in patients with HER2-overexpressing and HER2-low metastatic breast cancer (mBC). However, the mechanisms of action and resistance of this drug remain partially unclear. DAISY (NCT04132960) is a phase II, open-label study that included patients with mBC whose disease progressed after at least one line of chemotherapy in the metastatic setting. Patients were enrolled in three cohorts according to HER2 expression determined by immunohistochemistry (IHC); cohort 1: HER2-overexpressing (HER2 IHC 3 + or HER2 IHC 2+/ISH+, n = 72), cohort 2: HER2-low (HER2 IHC2+/ISH- or HER2 IHC 1+, n = 74), and cohort 3: HER2 IHC 0 mBC (n = 40). Patients were treated with T-DXd 5.4 mg/kg every 3 weeks until disease progression or unacceptable toxicity. In the full analysis set population (n = 177), the confirmed objective response rate (ORR) was of 70.6% (95% CI: 58.3–81) in cohort 1, 37.5% (95% CI: 26.4–49.7) in cohort 2, and 29.7% (95% CI: 15.9–47) in cohort 3 (p p = 0.007), and cohort 3 with shorter PFS (adjusted HR: 1.96, 95% IC: 1.21–3.15, p = 0.006) as compared to cohort 2. Exploratory analyses showed that HER2 spatial distribution predicted T-DXd response in patients with HER2-overexpressing mBC and that the transcriptomic response to T-DXd was different according to HER2 expression. No quantitative modulation of tumor microenvironment was observed after 6 to 8 weeks of treatment. Finally, recurrent mutations of the DNA repair gene SLX4 were identified in 20% of samples at resistance (4/20) as compared to 2% in baseline samples (2/88), suggesting that SLX4 mutations could mediate secondary resistance to T-DXd. These data suggest that HER2 is a key determinant of T-DXd efficacy. However, an antitumor activity is also observed in a subgroup of patients without detectable HER2 expression and resistance could be partially mediated by payload sensitivity.

Contains fulltext : 245198.pdf (Publisher’s version ) (Closed access) High stromal tumor-infiltrating lymphocytes (sTILs) in triple-negative breast cancer (TNBC) are associated with pathological complete response (pCR) after neoadjuvant chemotherapy (NAC). Histopathological assessment of sTILs in TNBC biopsies is characterized by substantial interobserver variability, but it is unknown whether this affects its association with pCR. Here, we aimed to investigate the degree of interobserver variability in an international study, and its impact on the relationship between sTILs and pCR. Forty pathologists assessed sTILs as a percentage in digitalized biopsy slides, originating from 41 TNBC patients who were treated with NAC followed by surgery. Pathological response was quantified by the MD Anderson Residual Cancer Burden (RCB) score. Intraclass correlation coefficients (ICCs) were calculated per pathologist duo and Bland-Altman plots were constructed. The relation between sTILs and pCR or RCB class was investigated. The ICCs ranged from -0.376 to 0.947 (mean: 0.659), indicating substantial interobserver variability. Nevertheless, high sTILs scores were significantly associated with pCR for 36 participants (90%), and with RCB class for eight participants (20%). Post hoc sTILs cutoffs at 20% and 40% resulted in variable associations with pCR. The sTILs in TNBC with RCB-II and RCB-III were intermediate to those of RCB-0 and RCB-I, with lowest sTILs observed in RCB-I. However, the limited number of RCB-I cases precludes any definite conclusions due to lack of power, and this observation therefore requires further investigation. In conclusion, sTILs are a robust marker for pCR at the group level. However, if sTILs are to be used to guide the NAC scheme for individual patients, the observed interobserver variability might substantially affect the chance of obtaining a pCR. Future studies should determine the 'ideal' sTILs threshold, and attempt to fine-tune the patient selection for sTILs-based de-escalation of NAC regimens. At present, there is insufficient evidence for robust and reproducible sTILs-guided therapeutic decisions.

Background: Everolimus (EVE) addition to adjuvant hormonotherapy (HT) for high-risk early breast cancer (BC) did not improve 3-year disease-free survival (DFS) compared with ET alone in the randomized UNIRAD trial (NCT01805271) (1). Most patients (pts) withdrew from EVE for adverse events nearly midway before the expected treatment duration of 2 years. The main EVE target involves m-TOR-induced S6 protein phosphorylation, which is controlled by the molecular circadian clock in mice and cells. Toward the analysis of possible circadian time-dependencies in EVE toxicities and efficacy, we first determine the actual distribution of the daily times chosen by the patients for both oral EVE and HT intakes. Patients and methods: The registered pts were asked to record the clock hours they chose for both HT and EVE or placebo (PLAC) intakes within four possible daily 6-h slots, i.e. from 06:00 to 11:59 (morning), 12:00 to 17:59 (midtime), 18:00 to 23:59 (evening), or 24:00 to 05:59, (night) in a daily diary throughout their participation in the trial. Modifications in times of drugs intake were reported. Comparisons between groups involved Kruskal-Wallis sum test and Pearson’s Chi-squared and Fisher’s exact tests. Results: Out of 1,278 randomized patients, 1063 (83,1 %) recorded the times of EVE or PLAC intakes, 852 recorded those for HT intakes. Only 10 pts reported night EVE/PLAC intakes and were not considered here. Of the 1053 evaluated pts; 549 pts took EVE/PLAC in the morning, 82 pts at midtime and 422 in the evening. As compared with evening intakes, morning or midtime intakes of EVE or PLAC were significantly associated with an older age, and post-menopausal status, whilst younger and premenopausal women preferentially chose evening intakes (p< 0.001 for both). Consistently, HT with aromatase inhibitors (AI) were mostly taken in the morning or at midtime, whereas tamoxifene (TAM) was mostly taken the evening (p = 0.001). Tumor size, lymph nodes involvement, histological grade, hormonal receptors status, and EVE initial dose were similarly distributed among the three time slots (Table 1). A similar distribution of oral intake times as in the whole timing study population was found according to age, menopausal status and HT type in the EVE arm (N=508 pts), and in the HT population (+/- EVE or PLAC) (N=852 pts). Initial oral timing intake was modified for EVE by 50 of 508 pts (10%) and for HT by 10 of 852 pts (1%). Conclusion: To the best of our knowledge, it is the first time that the patients’ spontaneous selection of daily times for oral intakes of a targeted agent (EVE) and HT is reported in a large series of early breast cancer pts. Age and menopausal status were important determinants of patient-selected daily timing intakes of both EVE and HT, as well as HT types. These findings will be carefully considered in the analyses of possible EVE and HT timing effects on adverse events and efficacy of the current adjuvant regimens. 1) Bachelot T et al, J Clin Oncol. 2022 May 23 Citation Format: Sylvie Giacchetti, Anne-Sophie Hamy, Thomas Bachelot, Jérôme Lemonnier, Fabrice Andre, David A. Cameron, Judith Bliss, Sylvie Chabaud, Anne-Claire Hardy-Bessard, Magali Lacroix-Triki, Jean-Luc Canon, Hervé R. Bonnefoi, Mario Campone, Paul Cottu, Florence Dalenc, Annabelle Ballesta, Francis Lévi, Enora Laas. Patients’ selection of daily timing of oral intake of adjuvant hormonotherapy (HT) and everolimus (EVE) for high risk early breast cancer in the UCBG-UNIRAD phase III trial. [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 P2-02-07.

Histopathological assessment of ductal carcinoma in situ, a nonobligate precursor of invasive breast cancer, is characterized by considerable interobserver variability. Previously, post hoc dichotomization of multicategorical variables was used to determine the "ideal" cutoffs for dichotomous assessment. The present international multicenter study evaluated interobserver variability among 39 pathologists who performed upfront dichotomous evaluation of 149 consecutive ductal carcinomas in situ. All pathologists independently assessed nuclear atypia, necrosis, solid ductal carcinoma in situ architecture, calcifications, stromal architecture, and lobular cancerization in one digital slide per lesion. Stromal inflammation was assessed semiquantitatively. Tumor-infiltrating lymphocytes were quantified as percentages and dichotomously assessed with a cutoff at 50%. Krippendorff's alpha (KA), Cohen's kappa and intraclass correlation coefficient were calculated for the appropriate variables. Lobular cancerization (KA = 0.396), nuclear atypia (KA = 0.422), and stromal architecture (KA = 0.450) showed the highest interobserver variability. Stromal inflammation (KA = 0.564), dichotomously assessed tumor-infiltrating lymphocytes (KA = 0.520), and comedonecrosis (KA = 0.539) showed slightly lower interobserver disagreement. Solid ductal carcinoma in situ architecture (KA = 0.602) and calcifications (KA = 0.676) presented with the lowest interobserver variability. Semiquantitative assessment of stromal inflammation resulted in a slightly higher interobserver concordance than upfront dichotomous tumor-infiltrating lymphocytes assessment (KA = 0.564 versus KA = 0.520). High stromal inflammation corresponded best with dichotomously assessed tumor-infiltrating lymphocytes when the cutoff was set at 10% (kappa = 0.881). Nevertheless, a post hoc tumor-infiltrating lymphocytes cutoff set at 20% resulted in the highest interobserver agreement (KA = 0.669). Despite upfront dichotomous evaluation, the interobserver variability remains considerable and is at most acceptable, although it varies among the different histopathological features. Future studies should investigate its impact on ductal carcinoma in situ prognostication. Forthcoming machine learning algorithms may be useful to tackle this substantial diagnostic challenge. ispartof: MODERN PATHOLOGY vol:33 issue:3 pages:354-366 ispartof: location:United States status: published

Neoadjuvant therapy is an increasing treatment option in the management of breast cancer. The tumor response to neoadjuvant therapy, especially the pathological complete response, is a validated endpoint frequently used in clinical trials. However, there is still a lack of standardization for the surgical specimen management in the neoadjuvant setting. This leads to heterogeneity in the specimen handling and might lead to significant bias for the prognostic assessment of patients or in clinical trials. The GEFPICS group, composed of expert breast cancer pathologists, herein presents guidelines for the management of breast and axillary specimen before treatment (management of biopsy, items of the pathological report) and after neoadjuvant therapy (specimen handling, histological assessment of response, items of the pathological report and response grading systems).

The last international guidelines on HER2 determination in breast cancer have been updated in 2018 by the American Society of Clinical Oncology and College of American Pathologists, on the basis of a twenty-year practice and results of numerous clinical trials. Moreover, the emerging HER2-low concept for 1+ and 2+ non amplified breast cancers lead to refine French practices for HER2 status assessment. The GEFPICS group, composed of expert pathologists, herein presents the latest French recommendations for HER2 status evaluation in breast cancer, taking into account the ASCO/CAP guidelines and introducing the HER2-low concept. In the era of personalized medicine, HER2 status assessment remains one of the most important biomarkers in breast cancer and its quality guaranties the optimal patients' care. French pathologists' commitment in theranostic biomarker quality is more than ever required to provide the most efficient cares in oncology.

Expression of hormone receptor (HR) for estrogens (ER) and progesterone (PR) and HER2 remains the cornerstone to define the therapeutic strategy for breast cancer patients. We aimed to compare phenotypic profiles between matched primary and metastatic breast cancer (MBC) in the ESME database, a National real-life multicenter cohort of MBC patients. Patients with results available on both primary tumour and metastatic disease within 6 months of MBC diagnosis and before any tumour progression were eligible for the main analysis. Among the 16,703 patients included in the database, 1677 (10.0%) had available biopsy results at MBC diagnosis and on matched primary tumour. The change rate of either HR or HER2 was 27.0%. Global HR status changed (from positive = either ER or PR positive, to negative = both negative; and reverse) in 14.2% of the cases (expression loss in 72.5% and gain in 27.5%). HER2 status changed in 7.8% (amplification loss in 45.2%). The discordance rate appeared similar across different biopsy sites. Metastasis to bone, HER2+ and RH+/HER2- subtypes and previous adjuvant endocrine therapy, but not relapse interval were associated with an HR discordance in multivariable analysis. Loss of HR status was significantly associated with a risk of death (HR adjusted = 1.51, p = 0.002) while gain of HR and HER2 discordance was not. In conclusion, discordance of HR and HER2 expression between primary and metastatic breast cancer cannot be neglected. In addition, HR loss is associated with worse survival. Sampling metastatic sites is essential for treatment adjustment.

Salivary gland-like tumours are described in the breast but remain very rare and difficult to diagnose in this location. Only 37 cases of mucoepidermoid carcinoma have been described in the literature. We report the challenging diagnosis of a mucoepidermoid carcinoma sampled by core biopsy in a 51-year-old woman.

Background The EndoPredict (EP) test has been developed and validated for assessing recurrence risk in patients with estrogen receptor (ER)-positive HER2-negative breast cancer (BC). This test is based on the expression of 12 genes (molecular score), combined with clinicopathological criteria (i.e. tumor size and nodal status) (EPclin risk score). For node-positive patients, the weight given to the node status in the EPclin score is similar when considering pN1mi (]0.2-2mm]) or pN1 (>2mm, 1-3 positive lymph nodes). Our aim was to characterize the EPclin classification of the pN1mi subgroup in the French national registry for molecular signatures in ER+ BC. Methods Since April 2016, nine French laboratories using EP test in clinical practice prospectively implement a national registry for molecular prognostic signatures in ER+ BC. We analyzed the pN1mi subgroup with regards to their clinico-pathological characteristics, molecular EP score and EPclin risk score. Using the definition formula of the EPclin score [EPclin=0.35t + 0.64n + 0.28EP, with n=1 for pN0, 2 for pN1mi/pN1, 3 for pN2, 4 for pN3], we could calculate a hypothetical EPclin score if the pN1mi had been considered as pN0 [n factor=1]. Results By the end of 2017, the database included 1246 EP tests performed in routine practice, including 67 (5.4%) pN1mi. The pN1mi BC were ER+ HER2- (67/67, 100%), invasive carcinoma of no special type in 52/67 (78%), with a median tumor size of 18 mm (range 7-45; pT1c in 40/67). Among these, 22 were classified as EPclin low and 45 as EPclin high, with a median EP score of 6 (range 2-14), a median EPclin score of 3.70 (range 3-6), and a median relapse risk at 10-year of 15%(range 5-73). Most interestingly, 23/67 (34%; i.e. 1.8% of all EP tests performed) pN1mi BC displayed an EPclin score comprised between 3.4 and 4, just above the cut-off value of 3.3: these cases (and only these cases) would have been classified in a different risk category (i.e. EPclin low risk) if the node status would have been considered as negative. Conclusion With regards to EndoPredict test in pN1mi BC - and the persistent debate as to whether they should bear the same weight as node-positive (pN1) or negative (pN0) tumors - categorization in the EPclin class is not likely to be impacted by the node factor weight in the vast majority (>65%) of the pN1mi cases and >98% of all patients tested with EP. Only cases with an EPclin between 3.4 and 4 might be impacted. Citation Format: LaCroix-Triki M, Arnould L, MacGrogan G, Penault-Llorca F, Haudebourg J, Tas P, Garnier A, Vincent-Salomon A, Miquel C, Lehmann-Che J, Callens C, Quillien V, Cayre A, Lamy P-J, Rouleau E, De Cremoux P. EndoPredict prognostic signature in pN1mi, estrogen receptor-positive breast cancer: analysis of the French national registry for molecular signatures [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-23.

Background: Therapeutic options at diagnosis for metastatic breast cancers (MBC) differ largely according to cancer phenotype (namely, hormone receptor (HR) and HER2 status). Reported discordance rates between primary tumor and metastasis vary widely in literature, with a median of 18% for estrogen receptor, 31% for progesterone receptor and 10% for HER2. The present study aimed to compare phenotypic profiles between primary and MBC in the real-life setting. Patients (pts) and methods: Epidemio-Strategy and Medical Economics (ESME)MBC data platform (NCT03275311) is a French national, multicenter, observational cohort using clinical trials' methodology for data capture, monitoring and quality controls. At the time of analysis, it comprised data of 16703 consecutive newly diagnosed MBC pts (1/01/08-31/12/14) treated in 18 French comprehensive cancer centres. The primary endpoint was the discordance rate of HR and HER2 status between primary tumor and MBC (biopsy of metastatic site done within 6 months of MBC diagnosis). Only patients with both histological reports available were considered. Potential factors associated with phenotype discordance were assessed in a multivariate logistic regression. Results: 2933 out of 16703 (17.6%) had a biopsy in the first 6 months of metastatic disease. HR and/or HER2 status was available in 1677 pts. The discordance rate between primary and matched MBC was 14.2% (222/1566) for HR: loss of expression in 72.5%, gain in 27.5%. For HER2, the discordance rate was 7.8% (84/1076): 45.2% of losses and 54.8% of gains of expression. The primary HR+/HER2+ subgroup had the highest rate of changes: 53% (49/92) with either a loss of HR (43%), loss of HER2 (43%) or a loss of both (14%). 18% (33/181) of primary triple-negative breast cancer (TNBC) had a phenotypic change with a majority of HR gain (79%). In multivariate analysis, administration of adjuvant chemotherapy +/- targeted therapy was the sole independent predictor of HR status modification (OR: 1.73, 95%CI 1.27-2.36, p=0.001). The presence of a mixed histology was the only predictor of HER2 discordance (OR =2.57, 95%CI 1.19-5.55, p=0.016). Patient characteristics Total population (n=16703)Pts with primary and MBC phenotype available (n=1677)Age at metastatic diagnosis Median (range)61 (19-99)60 (24-93)De novo MBC4507 (27.1%)221 (13.2%)Number of metastatic sites Median (range)1 (1-9)2 (1-7)MBC sites Brain1200 (7.2%)138 (8.2%)Visceral7755 (46.4%)928 (55.3%)Non-visceral7748 (46.4%)611 (36.4%)Phenotypic profileN = 2933N=1677TNBC356 (18.5%)272 (19.3%)HR+/HER2-1251 (65.0%)917 (65.2%)HR-/HER2+150 (7.8%)105 (7.5%)HR+/HER2+168 (8.7%)112 (8%)Missing1008271Metastatic site samplingN=2933N=1677Bone692 (24.2%)419 (25.5%)Liver514 (18.0%)355 (21.6%)Skin379 (13.3%)203 (12.4%)Node306 (10.7%)169 (10.3%)Lung258 (9.0%)168 (10.2%)Pleura283 (9.9%)121 (7.4%)CNS/CSF*132 (4.6%)42 (2.6%)Other or multiple296 (10.3%)165 (10.0%)Missing7335* CNS= central nervous system, CSF=cerebro-spinal fluid Conclusion: Biopsy and phenotype re-evaluation of MBC early in the disease course has a confirmed potential significant therapeutic impact in this large scale real life setting and should be proposed as often as possible. Citation Format: Lefevre S, Lusque A, Joyon N, Arnould L, Penault-Llorca F, MacGrogan G, Treilleux I, Vincent-Salomon A, Haudebourg J, Maran-Gonzalez A, Charafe-Jauffret E, Courtinard C, Franchet C, Verriele V, Brain E, Tas P, Delaloge S, Filleron T, LaCroix-Triki M. Phenotypic discordance between primary and metastatic breast cancer (MBC) in a large scale real-life multicentre French cohort [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-05.

Background Several validated molecular subtyping tests for breast cancer based on gene expression profiling are now routinely used in clinical practice.The Prosigna® breast cancer (BC) prognostic gene signature assay identifies a gene-expression profile that permits the classification of tumors into subtypes and gives a score for the risk of recurrence (ROR) at 10 years. The assay uses the 50-gene expression profile, weighted together with clinical variables, to generate a risk category and numerical score. The score is reported on a 0-100 scale, for hormone receptor positive BC. Prosigna test results classified tumors according to intrinsic subtypes (Lum A, Lum B, HER2-enriched, basal-like) and ROR risk groups (low risk, 0-40; intermediate risk, 41-60; and high risk, 61-100). For node-positive patients, the weight given to the node status is similar when considering pN1mi ([0.2-2mm]) or pN1 (>2mm, 1-3 positive lymph nodes). Our aim was to characterize the Prosigna test classification of the pN1mi subgroup in the French national registry for molecular signatures in ER+ BC. Methods Since 2018, four French laboratories using Prosigna test in clinical practice retrospectively implement a national registry for molecular prognostic signatures in ER+ BC. We analyzed the pN1mi subgroup with regards to their clinico-pathological characteristics, Prosigna test results and ROR risk score. Using the definition formula of the prosigna algorithm, we could calculate a hypothetical score if the pN1mi has been considered as pN0 and redefine risk categories for pN1mi breast cancers. Results The database included 886 tests performed in routine practice, including 91 (10.3%) pN1mi. The pN1mi BC were ER+ HER2- (88/91, 96.7%), invasive carcinoma of no special type in 81/91 (89%), with a median tumor size of 23 mm (range 12-60). Among these, the median ROR score was 44, and 51/91 tumors (56%) were classified as LumA tumors, 34/91 (41%) as LumB, two asHER2-enriched and one as basal-like. Interestingly, the probability of distant recurrence was 26% if pN1mi BC were considered as N+ but lowered to 10% if considered as pN0. Among the different molecular subtypes, the change from pN1 top N0 has different weight: in Lum A tumors, the switch in the probability of distant recurrences was 13 to 6% according to pN categorization of the pN1mi BC, and the median ROR score moved from 27 to 6 with 15/51(29%) of Lum A tumors considered as high risk if pN1 but only 1/51 if pN0; 31/51 (61%) versus 14/51 (27.5%) were in the intermediate risk group, and only 5/51 (10%) versus 34 (67%) in the low risk group. For LumB tumors, the switch in the probability of distant recurrences was 29% to 17% according to pN categorization and and the median ROR score moved from 60 to 15 with 36/37(97.3%) of Lum B tumors considered as high risk if pN1but only 13/37(35%) ifp N0; 1/37 versus 20/37 (54%) were in the intermediate risk group, and none of the 37 LumB versus 1 in the low risk group. Conclusion With regards to Prosigna test in pN1mi BC - and the persistent debate as to whether they should bear the same weight as pN1 pN0 tumors - categorization in ROR risk group is likely to be impacted by the node factor weight, and more importantly among Lum B tumors. Citation Format: Charafe-Jauffret E, Duprez-Paumier R, Berghian A, Penault-Llorca F, Dauplat MM, Boucraut A, Cohen M, Houvenaeghel G, Maroc C, Pradines A, Cayre A, Etancelin P, Lacroix-triki M. Prosigna prognostic signature in pN1mi, estrogen receptor-positive breast cancer:the pN categorization impacts the BC risk stratification [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-11-10.

Background Treatment strategies for metastatic breast cancer (MBC) have made great strides over the past 10 years. Real-world data allow us to evaluate the actual benefit of new treatments. ESME (Epidemio-Strategy-Medico-Economical)-MBC, a nationwide observational cohort (NCT03275311), gathers data of all consecutive MBC patients who initiated their treatment in 18 French Cancer Centres since 2008. Patients and methods We evaluated overall survival (OS) in the whole cohort (N = 20 446) and among subtypes: hormone receptor positive, human epidermal growth factor 2 negative (HR+/HER2−; N = 13 590), HER2+ (N = 3919), and triple-negative breast cancer (TNBC; N = 2937). We performed multivariable analyses including year of MBC diagnosis as one of the covariates, to assess the potential OS improvement over time, and we described exposure to newly released drugs at any time during MBC history by year of diagnosis (YOD). Results The median follow-up of the whole cohort was 65.5 months (95% CI 64.6-66.7). Year of metastatic diagnosis appears as a strong independent prognostic factor for OS [Year 2016 HR 0.89 (95% CI 0.82-0.97); P = 0.009, using 2008 as reference]. This effect is driven by the HER2+ subcohort, where it is dramatic [Year 2016 HR 0.52 (95% CI 0.42-0.66); P < 0.001, using 2008 as reference]. YOD had, however, no sustained impact on OS among patients with TNBC [Year 2016 HR 0.93 (95% CI 0.77-1.11); P = 0.41, using 2008 as reference] nor among those with HR+/HER2– MBC [Year 2016 HR 1.02 (95% CI 0.91-1.13); P = 0.41, using 2008 as reference]. While exposure to newly released anti-HER2 therapies appeared very high (e.g. >70% of patients received pertuzumab from 2016 onwards), use of everolimus or eribulin was recorded in less than one-third of HR+/HER2– and TNBC cohorts, respectively, whatever YOD. Conclusion OS has dramatically improved among HER2+ MBC patients, probably in association with the release of several major HER2-directed therapies, whose penetrance was high. This trend was not observed in the other subtypes, but the impact of CDK4/6 inhibitors cannot yet be assessed., Highlights • OS of HER2+ MBC patients keeps improving over time [Year 2016 HR 0.52 (95% CI 0.42-0.66); P < 0.001, using 2008 as reference]. • This effect seems timely related to the release of drugs demonstrated to improve survival in clinical trials. • OS gains observed in real life among HER2+ MBC patients are at least equivalent to those observed in clinical trials. • YOD had no sustained impact on OS among patients with TNBC and luminal MBC. • The impact of CDK4/6 inhibitors cannot yet be assessed in this cohort.

Background: The HER2-targeted antibody-drug conjugate (ADC) trastuzumab deruxtecan (T-DXd) demonstrated efficacy in heavily pretreated HER2-over- and HER2-low expressing ABC (1, 2). We aimed to assess the activity of T-DXd in HER2-over-, HER2-low and HER2-nul expressing ABC, to describe the drug mechanisms of action in the 3 cohorts and to identify biomarkers associated to drug response or resistance. Study Description: DAISY is a multicenter, open-label phase II trial designed to assess the efficacy of single agent T-DXd at 5.4 mg/kg dose in ABC with extensive biomarkers analysis. Three cohorts of patients were included: Cohort 1 (HER2 over-expressing: HER2 3+ on immunohistochemistry (IHC) or HER2 IHC2+/in situ hybridization [ISH]+), Cohort 2 (HER2 low-expressing: IHC1+ or IHC2+/ISH-) and cohort 3 (HER2-nul: IHC0+). Biopsy of metastatic sites was performed: at baseline, on treatment (mandatory for cohort 1, optional for cohort 2/3) and at tumor progression; blood samples for ctDNA were collected at baseline. The primary endpoint was the Best Overall Response (BOR) in each cohort, according to the investigator assessment. Secondary endpoints were BOR by central assessment, clinical benefit rate, duration of response (DOR), progression-free (PFS), overall survival (OS) and safety. Results:185 women and 1 man were enrolled between November 2019 and March 2021. Among the patients enrolled in the safety population (see Table 1), median (range) age was 55 (24-82) years, all received at least one prior line of therapy and 12 patients were TN. Table 2 shows investigator-reported T-Dxd activity in the 3 cohorts at a median follow-up of 10.1 months [95%CI: 9.2-11.1]. A total of 170 patients (95%) had at least one treatment-related toxicity. Key grade ≥3 treatment-related toxicities included neutropenia (10.6% of patients), fatigue (5.6%), leucopenia (4.5%), vomiting (4.5%) and anemia (3.4%). A total of 4 patients had drug-related interstitial lung disease or pneumonitis (grade 1 in 3 patients and grade 2 in 1 patient), 11 patients discontinued treatment due to treatment-related adverse events. No drug-related deaths occurred. Conclusions: T-DXd showed clinically meaningful activity in patients with HER2-overexpressing ABC and interestingly also in those with HER2low and HER2-nul ABC. Safety profile was consistent with previous reports. 1.Modi S et al N Engl J Med 2020 2.Mosi S et al J Clin Oncol 2020 Table 1.Analysis populationsTotalCohort 1 (HER2 over-expressing)Cohort 2 (HER2 low-expressing)Cohort 3 (HER2 non-detected)Enrolled population186727440Safety population*179687338 (including 12 TN)Full analysis Set**176687236TN: Triple Negative. *: safety population = enrolled population except 7 patients who did not receive at least one dose of study drug. **: Full Analysis Set = safety population except 3 patients (2 who did not have a valid first post-baseline assessment of disease status or who did not have progressive disease and 1 who did not have at least one radiologically measurable lesion according to RECIST v1.1) Table 2.T-DXd activity in the three cohorts according to investigator assessmentTotalCohort 1Cohort 2Cohort 3BOR confirmedn/N82/176 (46.6%)47/68 (69.1%)24/72 (33.3%)11/36 (30.6%)[95%CI][39.1; 54.2][56.7; 79.8][22.7; 45.4]16.3; 48.1]Median DORmonths7.69.97.66.8[95%CI][6.2; 9.7][5.4; NR][4.4; 8.7][2.8; 8.3]Median PFSmonths6.911.16.74.2[95%CI][6.7; 8.7][8.4; NR][4.6; 8.5][2.1; 6.9]NR: Not Reached Citation Format: Véronique Diéras, Elise Deluche, Amélie Lusque, Barbara Pistilli, Thomas Bachelot, Jean-Yves Pierga, Frédéric Viret, Christelle Levy, Laura Salabert, Fanny Le Du, Florence Dalenc, Christelle Jouannaud, Laurence Venat-Bouvet, Jean-Philippe Jacquin, Xavier Durando, Thierry Petit, Céline Mahier - Aït Oukhatar, Thomas Filleron, Maria Fernanda Mosele, Magali Lacroix-Triki, Agnès Ducoulombier, Fabrice André. Trastuzumab deruxtecan (T-DXd) for advanced breast cancer patients (ABC), regardless HER2 status: A phase II study with biomarkers analysis (DAISY) [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 PD8-02.

Background: The double blind randomized UNIRAD trial (NCT01805271) showed no evidence that adding Everolimus (EVE) to adjuvant endocrine therapy (EHT) for high-risk early breast cancer (BC) improved 3-year disease-free survival (iDFS) compared with EHT alone. In this trial, high risk was defined by any T and either ≥4N+, or ≥1N+ after neoadjuvant treatment, or ≥1N+ and EPclin high risk (EPCH) score ≥3.3. This sub analysis is aimed to verify prognostic added value of EndoPredict test results on outcomes in patients screened for the UNIRAD study.. Material and methods: From May 2015 to March 2020, 777 patients were screened with the EndoPredict test. Complete results were obtained for 767 of them. 662 pts were classified as EPCH and 429 were randomized in UNIRAD. 233 pts with EPCH and 105 pts with EPclin low risk (EPCL) were not randomized but followed up for iDFS. Statistical analysis: Kaplan-Meier estimates the association of the integrated molecular-clinico-pathologic EPclin score, and the 12-gene molecular EP score, with iDFS (primary endpoint) and dMFS (secondary endpoint). Independent prognostic added value of EPclin score was tested in a multivariate Cox model after adjusting on tumor characteristics (Grade and T, N). A two-sided p-value less than 0.05 considered as statistically significant, 95% confidence intervals reported with HR. Results: Median follow-up of the cohort was 36.6 mo (0-69) since EndoPredict test. As for the whole population, there was no significant difference in iDFS between treatment arms in the randomized EPCH group. On the other hand, EPclin was an independent prognostic factor for iDFS. 36 mo relapse rate from testing for patients in the EPCL group and the EPCH group was 0% and 7%, respectively (HR supposing continuous EPclin score: 2.36, 95%CI: 1.7-3.3, p < .0001). This difference remained significant when assessed in a cox model with tumor size, number of positive nodes and tumor grade (HR: 1.96, 95%CI: 1.32-2.9, p=0.0008). Furthermore, EPclin results was independently correlated to distant metastatic free survival: 36 mo dMFS for patient in the EPCL and EPCH group was 100% and 94%, respectively (adjusted HR: 2.13, 95%CI:11.3-3.4, p = .0014). Of interest when assessing prognostic of patients within quartiles of EPclin Score ( Citation Format: Frederique Penault-Llorca, Florence Dalenc, Sylvie Chabaud, Paul Cottu, Djelila Allouache, David Cameron, Jean-Philippe Jacquin, Julien Grenier, Laurence Venat Bouvet, Apurna Jegannathen, Mario Campone, Francesco Del Piano, Marc Debled, Anne-Claire Hardy-Bessard, Sylvie Giacchetti, Philippe Barthelemy, Laure Kaluzinski, Audrey Mailliez, Marie-Ange Mouret-Reynier, Eric Legouffe, Anne Cayre, Mathilde Martinez, Catherine Delbaldo, Delphine Mollon-Grange, E. Jane Macaskill, Matthew Sephton, Laëtitia Stefani, Blaha Belgadi, Matthew Winter, Hubert Orfeuvre, Magali Lacroix-Triki, Herve Bonnefoi, Judith Bliss, Jean-Luc Canon, Jerome Lemonnier, Fabrice Andre, Thomas Bachelot. Prognostic value of EndoPredict test in patients screened for UNIRAD, a UCBG randomized, double blind, phase III international trial evaluating the addition of everolimus (EVE) to adjuvant hormone therapy (HT) in women with high risk HR+, HER2- early breast cancer (eBC) [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 PD9-08.

International audience; Background: Diagnosis of atypical breast lesions (ABLs) leads to unnecessary surgery in 75-90% of women. We have previously developed a model including age, complete radiological target excision after biopsy, and focus size that predicts the probability of cancer at surgery. The present study aimed to validate this model in a prospective multicenter setting.- methods: Women with a recently diagnosed ABL on image-guided biopsy were recruited in 18 centers, before wire-guided localized excisional lumpectomy. Primary outcome was the negative predictive value (NPV) of the model.Results: The NOMAT model could be used in 287 of the 300 patients included (195 with ADH). At surgery, 12 invasive (all grade 1), and 43 in situ carcinomas were identified (all ABL: 55/287, 19%; ADH only: 49/195, 25%). The area under the receiving operating characteristics curve of the model was 0.64 (95% CI 0.58-0.69) for all ABL, and 0.63 for ADH only (95% CI 0.56-0.70). For the pre-specified threshold of 20% predicted probability of cancer, NPV was 82% (77-87%) for all ABL, and 77% (95% CI 71-83%) for patients with ADH. At a 10% threshold, NPV was 89% (84-94%) for all ABL, and 85% (95% CI 78--92%) for the ADH. At this threshold, 58% of the whole ABL population (and 54% of ADH patients) could have avoided surgery with only 2 missed invasive cancers.Conclusion: The NOMAT model could be useful to avoid unnecessary surgery among women with ABL, including for patients with ADH.