Integration of Pathological Criteria and Immunohistochemical Evaluation for Invasive Lobular Carcinoma Diagnosis: Recommendations From the European Lobular Breast Cancer Consortium.

Invasive lobular carcinoma (ILC) is the second most frequent type of breast cancer (BC) and its peculiar morphology is mainly driven by inactivation of CDH1, the gene coding for E-cadherin cell adhesion protein. ILC-specific therapeutic and disease-monitoring approaches are gaining momentum in the clinic, increasing the importance of accurate ILC diagnosis. Several essential and desirable morphologic diagnostic criteria are currently defined by the World Health Organization, the routine use of immunohistochemistry (IHC) for E-cadherin is not recommended. Disagreement in the diagnosis of ILC has been repeatedly reported, but interpathologist agreement increases with the use of E-cadherin IHC. In this study, we aimed to harmonize the pathological diagnosis of ILC by comparing 5 commonly used E-cadherin antibody clones (NCH-38, EP700Y, Clone 36, NCL-L-E-cad [Clone 36B5], and ECH-6). We determined their biochemical specificity for the E-cadherin protein and IHC staining performance according to type and location of mutation on the CDH1 gene. Western blot analysis on mouse cell lines with conditional E-cadherin expression revealed a reduced specificity of EP700Y and NCL-L-E-cad for E-cadherin, with cross-reactivity of Clone 36 to P-cadherin. The use of IHC improved interpathologist agreement for ILC, lobular carcinoma in situ, and atypical lobular hyperplasia. The E-cadherin IHC staining pattern was associated with variant allele frequency and likelihood of nonsense-mediated RNA decay but not with the type or position of CDH1 mutations. Based on these results, we recommend the indication for E-cadherin staining, choice of antibodies, and their interpretation to standardize ILC diagnosis in current pathology practice.

p53 Expression in Luminal Breast Cancer Correlates With TP53 Mutation and Primary Endocrine Resistance.

TP53 mutation is associated with primary endocrine resistance in luminal breast cancer (BC). Nuclear accumulation of p53, as determined by immunohistochemistry (IHC), is a surrogate marker for TP53 mutation. The immunohistochemical p53 index that defines a p53-positive status is not well established. This study determined the optimal p53 index cutoff to identify luminal BCs harboring TP53 mutations. In total, 364 luminal BCs from the West German Study Group ADAPT trial (NCT01779206) were analyzed for TP53 mutations by next-generation sequencing and for p53 expression by IHC (DO-7 antibody). P53 indices were determined by automated image analysis. All tumors were from patients treated with short-term preoperative endocrine therapy (pET; tamoxifen or aromatase inhibitor) before tumor resection. IHC evaluation included needle biopsies before therapy (baseline) and resections specimens after therapy (post-pET). Optimal p53 index cutoffs were defined with Youden statistics. TP53 mutations were detected in 16.3% of BC cases. The median p53 indices were significantly higher in TP53-mutated BCs compared to BCs harboring wild-type TP53 (baseline: 47.0% vs 6.4%, P < .001; post-pET: 50.1% vs 1.1%, P < .001). Short-term pET decreased p53 indices in BCs harboring wild-type TP53 (P < .001) but not in TP53-mutated BCs (P = .102). For baseline biopsies, the optimal p53 index cutoff was ≥34.6% (specificity 0.92, sensitivity 0.63, Youden index 0.54, accuracy: 0.87). For post-pET specimens, the optimal cutoff was ≥25.3% (specificity 0.95, sensitivity 0.65, Youden index 0.60, accuracy: 0.90). Using these cutoffs to define the p53 status, p53-positive BCs were >2-fold more common in pET nonresponders compared to pET responders (baseline: 37/162, 22.8% vs 18/162, 11.1%, P = .007; post-pET: 36/179, 20.1% vs 16/179, 8.9%, P = .004). In summary, IHC for p53 identifies TP53-mutated luminal BCs with high specificity and accuracy. Optimal cutoffs are ≥35% and ≥25% for treatment-naïve and endocrine-pretreated patients, respectively.

Molecular Profiling in Early ER + Breast Cancer to Aid Systemic Therapy Decisions.

PURPOSE OF REVIEW: Clinical decisions for (neo)adjuvant treatment in early breast cancer (eBC) have been based mostly on clinical factors over the last decades. We have reviewed development and validation of such assays in the HR + /HER2 eBC and discuss possible future directions in this field. RECENT FINDINGS: Increasing knowledge about the biology of hormone-sensitive eBC, based on the precise and reproducible multigene expression analysis, has led to a significant change in the treatment pathways and reduction of overtreatment in particular by chemotherapy in HR + /HER2 eBC with up to 3 positive lymph nodes based on results from several retrospective-prospective trials used several genomic assays and in particular prospective trials (TAILORx, RxPonder, MINDACT, and ADAPT used OncotypeDX® and Mammaprint®). Precise evaluation of tumor biology together with endocrine responsiveness assessment appears as promising tools for individualized treatment decisions together with clinical factors and menopausal status in early hormone-sensitive/HER2-negative breast cancer.

De-escalated neoadjuvant pertuzumab plus trastuzumab therapy with or without weekly paclitaxel in HER2-positive, hormone receptor-negative, early breast cancer (WSG-ADAPT-HER2+/HR-): survival outcomes from a multicentre, open-label, randomised, phase 2 trial.

BACKGROUND: Several de-escalation neoadjuvant strategies have been investigated to reduce the use of chemotherapy in HER2-positive early breast cancer using pathological complete response as a surrogate endpoint; there are few survival data from these trials. Here, we report 5-year survival data in the WSG-ADAPT-HER2+/HR- trial and address the effect of pathological complete response, early therapy response, and molecular subtype. METHODS: WSG-ASAPT-HER2+/HR-, a part of the ADAPT umbrella trial performed in patients with different subtypes of early breast cancer, was an investigator-initiated, multicentre, open-label, randomised, phase 2 trial done at 40 Breast Cancer Centres in Germany. Eligible patients were aged 18 years or older with histologically confirmed, unilateral, primary invasive, non-inflammatory early breast cancer, hormone receptor-negative and HER2-positive status, and an Eastern Cooperative Oncology Group performance status of 0 or 1 or a Karnofsky performance status of at least 80%. Patients were randomly assigned (5:2, block size 21, stratified by centre and clinical nodal status) to 12 weeks of either trastuzumab (8 mg/kg loading dose, then 6 mg/kg every 3 weeks) plus pertuzumab (840 mg loading dose, then 420 mg every 3 weeks) or trastuzumab plus pertuzumab plus paclitaxel (80 mg/m2 weekly); all drugs were administered intravenously. The primary objective of the trial was to compare the number of patients with a pathological complete response at surgery (ie, no invasive tumour cells in breast and lymph nodes [ypT0/is ypN0], the primary endpoint) in early responders (ie, low cellularity or Ki67 decrease ≥30% after 3 weeks) in the trastuzumab plus pertuzumab group versus all patients (irrespective of an early response) in the trastuzumab plus pertuzumab plus paclitaxel group. Non-inferiority was defined as a pathological complete response no worse than 23% lower in the early-responder proportion of patients in the trastuzumab plus pertuzumab group than in the entire trastuzumab plus pertuzumab plus paclitaxel group. The primary endpoint has been reported previously. Additionally, the primary objective of the ADAPT umbrella trial was the evaluation of the effect of pathological complete response on invasive disease-free survival. At investigator's discretion, further chemotherapy could be omitted in patients with a pathological complete response. Secondary survival endpoints were 5-year invasive disease-free survival, relapse-free survival, locoregional relapse-free survival, distant disease-free survival, and overall survival. The effect of pathological complete response on survival was estimated by Cox regression analysis. All analyses are reported in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01817452, and is closed to recruitment. FINDINGS: Between March 3, 2014, and Oct 6, 2015, 134 patients were recruited and randomly assigned to treatment, 92 to trastuzumab plus pertuzumab and 42 to trastuzumab plus pertuzumab plus paclitaxel. Median follow-up in survivors was 59·9 months (IQR 53·4-61·4). There were no significant differences between the treatment groups in invasive disease-free survival, relapse-free survival, locoregional relapse-free survival, distant disease-free survival, and overall survival. In the trastuzumab plus pertuzumab plus paclitaxel group and in the trastuzumab plus pertuzumab group, the proportions of patients achieving 5-year survival respectively were 98% (95% CI 84-100) and 87% (78-93) for invasive disease-free survival (hazard ratio [HR] 0·32, 95% CI 0·07-1·49; p=0·15); 98% (95% CI 84-100) and 89% (79-94) for relapse-free survival (HR 0·41, 95% CI 0·09-1·91; p=0·25); 100% (95% CI not estimable) and 95% (88-98) for locoregional relapse-free survival (HR 0·41, 95% CI 0·05-3·75; p=0·43); 98% (95% CI 84-100) and 92% (83-96) for distant disease-free survival (HR 0·35, 95% CI 0·04-3·12; p=0·36), and 98% (95% CI 84-100) and 94% (86-97) for overall survival (HR 0·41, 95% CI 0·05-3·63; p=0·43). Pathological complete response was associated with improved invasive disease-free survival (HR 0·14, 95% CI 0·03-0·64; p=0·011). Two invasive disease-free survival events occurred after a pathological complete response (one in each treatment group). INTERPRETATION: The WSG-ADAPT-HER2+/HR- trial showed good survival rates in patients with a pathological complete response after de-escalated 12-week trastuzumab plus pertuzumab with or without weekly paclitaxel. Omission of further chemotherapy did not affect invasive disease-free survival in patients with a pathological complete response. 12 weeks of weekly paclitaxel plus dual HER2 blockade could be an efficacious de-escalated neoadjuvant regimen in patients with hormone receptor-negative, HER2-positive early breast cancer with high pathological complete response rates and good 5-year outcomes. Further trials of this approach are ongoing. FUNDING: Roche, Bayer. TRANSLATION: For the German translation of the abstract see Supplementary Materials section.

Impact of stromal tumor-infiltrating lymphocytes (sTILs) on response to neoadjuvant chemotherapy in triple-negative early breast cancer in the WSG-ADAPT TN trial.

BACKGROUND: Higher density of stromal tumor-infiltrating lymphocytes (sTILs) at baseline has been associated with increased rates of pathological complete response (pCR) after neoadjuvant chemotherapy (NACT) in triple-negative breast cancer (TNBC). While evidence supports favorable association of pCR with survival in TNBC, an independent impact of sTILs (after adjustment for pCR) on survival is not yet established. Moreover, the impact of sTIL dynamics during NACT on pCR and survival in TNBC is unknown. METHODS: The randomized WSG-ADAPT TN phase II trial compared efficacy of 12-week nab-paclitaxel with gemcitabine versus carboplatin. This preplanned translational analysis assessed impacts of sTIL measurements at baseline (sTIL-0) and after 3 weeks of chemotherapy (sTIL-3) on pCR and invasive disease-free survival (iDFS). Predictive performance of sTIL-0 and sTIL-3 for pCR was quantified by ROC analysis and logistic regression; Kaplan-Meier estimation and Cox regression (with mediation analysis) were used to determine their impact on iDFS. RESULTS: For prediction of pCR, the AUC statistics for sTIL-0 and sTIL-3 were 0.60 and 0.63, respectively, in all patients; AUC for sTIL-3 was higher in NP/G. The positive predictive value (PPV) of "lymphocyte-predominant" status (sTIL-0 ≥ 60%) at baseline was 59.3%, though only 13.0% of patients had this status. To predict non-pCR, the cut point sTIL-0 ≤ 10% yielded PPV = 69.5% while addressing 33.8% of patients. Higher sTIL levels (particularly at 3 weeks) were independently and favorably associated with better iDFS, even after adjusting for pCR. For example, the adjusted hazard ratio for 3-week sTILs ≥ 60% (vs. < 60%) was 0.48 [0.23-0.99]. Low cellularity in 3-week biopsies was the strongest individual predictor for pCR (in both therapy arms), but not for iDFS. CONCLUSION: The independent impact of sTILs on iDFS suggests that favorable immune response can influence key tumor biological processes for long-term survival. The results suggest that the reliability of pCR following neoadjuvant therapy as a surrogate for survival could vary among subgroups in TNBC defined by immune response or other factors. Dynamic measurements of sTILs under NACT could support immune response-guided patient selection for individualized therapy approaches for both very low levels (more effective therapies) and very high levels (de-escalation concepts). TRIAL REGISTRATION: Clinical trials No: NCT01815242, retrospectively registered January 25, 2013.

The impact of anthracyclines in intermediate and high-risk HER2-negative early breast cancer-a pooled analysis of the randomised clinical trials PlanB and SUCCESS C.

BACKGROUND: Anthracycline/cyclophosphamide-taxane-containing chemotherapy (AC-T) is the standard of care in the adjuvant treatment of HER2-negative early breast cancer (EBC), but recent studies suggest omission of anthracyclines for reduced toxicity without compromising efficacy. METHODS: Based on individual patient data (n = 5924) pooled from the randomised Phase III trials PlanB and SUCCESS C, we compared disease-free survival (DFS) and overall survival (OS) between intermediate to high-risk HER2-negative EBC-patients treated with either six cycles of docetaxel/cyclophosphamide (TC6) or an AC-T regime using univariable and adjusted multivariable Cox regression models. RESULTS: AC-T conferred no significant DFS or OS advantage in univariable (DFS: hazard ratio (HR) for TC vs. AT 1.05, 95% confidence interval (CI): 0.89-1.24, P = 0.57; OS: HR 1.00, 95% CI: 0.80-1.26, P = 1.00) and adjusted multivariable analysis (DFS: HR 1.01, 95% CI: 0.86-1.19, P = 0.91; OS: HR 0.97, 95% CI: 0.77-1.22, P = 0.79). Patients receiving TC6 had significantly fewer grade 3-4 adverse events. Exploratory subgroup analysis showed that AC-T was associated with significantly better DFS and OS in pN2/3 patients, specifically in those with lobular histology. CONCLUSION: For most patients with HER2-negative EBC, AC-T is not associated with a survival benefit compared to TC6. However, patients with lobular pN2/pN3 tumours seem to benefit from anthracycline-containing chemotherapy.

ERBB2 mutation is associated with sustained tumor cell proliferation after short-term preoperative endocrine therapy in early lobular breast cancer.

Invasive lobular breast cancer (ILC) is a special breast cancer (BC) subtype and is mostly hormone receptor (HR)-positive and ERBB2 non-amplified. Endocrine therapy restrains tumor proliferation and is the mainstay of lobular BC treatment. Mutation of ERBB2 has been associated with recurrent ILC. However, it is unknown whether ERBB2 mutation impacts on the otherwise exquisite responsiveness of early ILC to endocrine therapy. We have recently profiled n = 622 HR-positive early BCs from the ADAPT trial for mutations in candidate genes involved in endocrine resistance, including ERBB2. All patients were treated with short-term preoperative endocrine therapy (pET, tamoxifen or aromatase inhibitors) before tumor resection. Tumor proliferation after endocrine therapy (post-pET Ki67 index) was determined prospectively by standardized central pathology assessment supported by computer-assisted image analysis. Sustained or suppressed proliferation were defined as post-pET Ki67 ≥10% or <10%. Here, we report a subgroup analysis pertaining to ILCs in this cohort. ILCs accounted for 179/622 (28.8%) cases. ILCs were enriched in mutations in CDH1 (124/179, 69.3%, P < 0.0001) and ERBB2 (14/179, 7.8%, P < 0.0001), but showed fewer mutations in TP53 (7/179, 3.9%, P = 0.0048) and GATA3 (11/179, 6.1%, P < 0.0001). Considering all BCs irrespective of subtypes, ERBB2 mutation was not associated with proliferation. In ILCs, however, ERBB2 mutations were 3.5-fold more common in cases with sustained post-pET proliferation compared to cases with suppressed post-pET proliferation (10/75, 13.3% versus 4/104, 3.8%, P = 0.0248). Moreover, ERBB2 mutation was associated with high Oncotype DX recurrence scores (P = 0.0087). In summary, our findings support that ERBB2 mutation influences endocrine responsiveness in early lobular BC.

Magnetic resonance imaging and ultrasound for prediction of residual tumor size in early breast cancer within the ADAPT subtrials.

BACKGROUND: Prediction of histological tumor size by post-neoadjuvant therapy (NAT) ultrasound and magnetic resonance imaging (MRI) was evaluated in different breast cancer subtypes. METHODS: Imaging was performed after 12-week NAT in patients enrolled into three neoadjuvant WSG ADAPT subtrials. Imaging performance was analyzed for prediction of residual tumor measuring ≤10 mm and summarized using positive (PPV) and negative (NPV) predictive values. RESULTS: A total of 248 and 588 patients had MRI and ultrasound, respectively. Tumor size was over- or underestimated by < 10 mm in 4.4% and 21.8% of patients by MRI and in 10.2% and 15.8% by ultrasound. Overall, NPV (proportion of correctly predicted tumor size ≤10 mm) of MRI and ultrasound was 0.92 and 0.83; PPV (correctly predicted tumor size > 10 mm) was 0.52 and 0.61. MRI demonstrated a higher NPV and lower PPV than ultrasound in hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-positive and in HR-/HER2+ tumors. Both methods had a comparable NPV and PPV in HR-/HER2- tumors. CONCLUSIONS: In HR+/HER2+ and HR-/HER2+ breast cancer, MRI is less likely than ultrasound to underestimate while ultrasound is associated with a lower risk to overestimate tumor size. These findings may help to select the most optimal imaging approach for planning surgery after NAT. TRIAL REGISTRATION: Clinicaltrials.gov , NCT01815242 (registered on March 21, 2013), NCT01817452 (registered on March 25, 2013), and NCT01779206 (registered on January 30, 2013).

Early response by MR imaging and ultrasound as predictor of pathologic complete response to 12-week neoadjuvant therapy for different early breast cancer subtypes: Combined analysis from the WSG ADAPT subtrials.

We evaluated the role of early response after 3 weeks of neoadjuvant treatment (NAT) assessed by ultrasound (US), magnetic resonance imaging (MRI) and Ki-67 dynamics for prediction of pathologic complete response (pCR) in different early breast cancer subtypes. Patients with HR+/HER2+, HR-/HER2- and HR-/HER2+ tumors enrolled into three neoadjuvant WSG ADAPT subtrials underwent US, MRI and Ki-67 assessment at diagnosis and after 3 weeks of NAT. Early response was defined as complete or partial response (US, MRI) and ≥30% proliferation decrease or <500 invasive tumor cells (Ki-67). Predictive values and area under the receiver operating characteristic (AUC) curves for prediction of pCR (ypT0/is ypN0) after 12-week NAT were calculated. Two hundred twenty-six had MRI and 401 US; 107 underwent both MRI and US. All three methods yielded a similar AUC in HR+/HER2+ (0.66-0.67) and HR-/HER2- tumors (0.53-0.63), while MRI and Ki-67 performed better than US in HR-/HER2+ tumors (0.83 and 0.79 vs 0.56). Adding MRI+/-Ki-67 increased AUC of US in HR-/HER2+ tumors to 0.64 to 0.75. MRI and Ki-67 demonstrated highest sensitivity in HR-/HER2- (0.8-1) and HR-/HER2+ tumors (1, both). Negative predictive value was similar for all methods in HR+/HER2+ (0.71-0.74) and HR-/HER2- tumors (0.85-1), while it was higher for MRI and Ki-67 compared to US in HR-/HER2+ subtype (1 vs 0.5). Early response assessed by US, MRI and Ki-67 is a strong predictor for pCR after 12-week NAT. Strength of pCR prediction varies according to tumor subtype. Adding MRI+/-Ki-67 to US did not improve pCR prediction in majority of our patients.

Association of TILs with clinical parameters, Recurrence Score® results, and prognosis in patients with early HER2-negative breast cancer (BC)-a translational analysis of the prospective WSG PlanB trial.

BACKGROUND: The presence of tumor-infiltrating lymphocytes has been associated with prognosis and chemotherapy response, particularly in high-risk breast cancer subtypes. There is limited data so far as to (i) how tumor-infiltrating lymphocyte (TIL) measurements correlate with genomic measurements such as the Oncotype DX Recurrence Score® and (ii) whether the survival impact of TIL measurements varies according to different adjuvant systemic therapies. METHODS: The WSG PlanB trial compared an anthracycline-free chemotherapy regimen (6x docetaxel/cyclophosphamide, TC) to an anthracycline-taxane sequence (4xEC followed by 4x docetaxel) in patients with intermediate-risk, HER2-negative early breast cancer (EBC). Patients with HR-positive HER2-negative EBC were further stratified to receive endocrine therapy alone vs. chemotherapy followed by endocrine therapy based on Recurrence Score results and nodal status. In this analysis, three independent observers quantified and categorized the presence of TILs among tumor samples from patients in PlanB. TIL measurements were correlated with clinical/pathological parameters and treatment outcome overall and according to the treatment arm. RESULTS: Disease-free survival (DFS) rates were significantly better (p = .04) in HR-negative patients with high vs. intermediate TIL levels and were higher in low vs. intermediate TIL patients, however with borderline significance only (p = .06). There were no significant differences among TIL categories in HR+ patients. High RS categories, HR-negative status, and high KI67 were independently and significantly associated with high TIL categories. There was no significant impact of TIL category on DFS in patients treated by endocrine therapy only; however, in patients receiving chemotherapy, DFS in the intermediate TIL category was lower than that in the other categories. CONCLUSION: Although the presence of high TILs is associated with negative prognostic parameters such as high KI67 and HR-negative status among patients with HR-positive HER2-negative EBC, patients with high TILs show a favorable 5-year DFS in both HR-positive/HER2-negative and triple-negative breast cancer.

Efficacy of deescalated chemotherapy according to PAM50 subtypes, immune and proliferation genes in triple-negative early breast cancer: Primary translational analysis of the WSG-ADAPT-TN trial.

In the neoadjuvant WSG-ADAPT-TN trial, 12-week nab-paclitaxel + carboplatin (nab-pac/carbo) was highly effective and superior to nab-paclitaxel + gemcitabine (nab-pac/gem) in triple-negative breast cancer regarding pathological complete response (pCR). Predictive markers for deescalated taxane/carbo use in TNBC need to be identified. Patients received 4 × nab-pac 125 mg/m2 (plus carbo AUC2 or gem 1,000 mg/m2 d1,8 q21). Expression of 119 genes and PAM50 scores by nCounter were available in 306/336 pretherapeutic samples. Interim survival analysis was planned after 36 months median follow-up. Basal-like (83.3%) compared to other subtypes was positively associated with pCR (38% vs. 20%, p = 0.015), as was lower HER2 score (p < 0.001). Proliferation biomarkers were positively associated with pCR, that is, PAM50 proliferation, ROR scores (all p < 0.004), higher Ki-67 (IHC; p < 0.001). For nab-pac/carbo, expression of immunological (CD8, PD1 and PFDL1) genes and proliferation markers (proliferation and ROR scores, MKI67, CDC20, NUF2, KIF2C, CENPF, EMP3 and TYMS) were positively associated with pCR (p < 0.05 for all). For nab-pac/gem, angiogenesis genes were negatively associated with pCR (ANGPTL4: p = 0.05; FGFR4: p = 0.02; VEGFA: p = 0.03). pCR after 12 weeks was strongly associated with favorable outcome (3y event-free survival: 92% vs. 71%, p < 0.001). In early TNBC, basal-like subtype, higher Ki-67 (IHC) and lower HER2 score were, associated with chemosensitivity. Chemoresistance pathways differed between the two taxane based combinations. Combination of proliferation/immune markers and PAM50 subtype could allow patient selection for further deescalated chemotherapy and/or immune treatment approaches.

Differential impact of prognostic parameters in hormone receptor-positive lobular breast cancer.

BACKGROUND: Invasive lobular breast cancer (BC) is the second most common BC subtype. Prognostic parameters (tumor classification, lymph node status, histologic grade, Oncotype DX recurrence score [RS], progesterone receptor status, and Ki67 index) were retrospectively studied in a large, prospective clinical trial encompassing 2585 patients who had hormone receptor-positive early BC (the West German Study Group PlanB trial). METHODS: BCs were centrally reviewed and classified as lobular (n = 353; 14%) or nonlobular (n = 2232; 86%). The median follow-up was 60 months. Five-year disease-free survival (DFS) estimates were obtained using the Kaplan-Meier method. Prognostic parameters were evaluated using Cox proportional hazard models. RESULTS: Lobular BC was associated with higher tumor classification, higher lymph node status, lower histologic grade, lower Ki67 index, and low or intermediate RS. The prevalence of high RS (RS range, 26-100) was 3-fold lower in patients who had lobular BC compared with those who had nonlobular BC (8% vs 24%; P < .001). However, 5-year DFS estimates for lobular and nonlobular BC were similar (92.1% and 92.3%, respectively; P = .673). In multivariate analyses, prognostic parameters for DFS in lobular BC included grade 3 (hazard ratio, 5.06; 95% CI, 1.91-13.39) and a pathologic lymph node status (pN) of pN3 (hazard ratio, 12.16; 95% CI, 3.87-38.24), but not RS. By contrast, prognostic parameters in nonlobular BC included grade 3 (hazard ratio, 1.65; 95% CI, 1.11-2.44), pN3 (hazard ratio, 3.68; 95% CI, 1.60-8.46), and high RS (hazard ratio, 2.49; 95% CI, 1.69-3.68). CONCLUSIONS: Lobular BC is associated with low and intermediate RS, although 5-year DFS is similar to that of nonlobular BC. The effect of the RS in lobular BC appears to be distinct from that in nonlobular BC. For risk assessment, the RS needs to be complemented by clinicopathologic parameters for therapy decision making.

ERBB2 mutation frequency in lobular breast cancer with pleomorphic histology or high-risk characteristics by molecular expression profiling.

HER2-positive breast cancer is defined by amplification or overexpression of the HER2/ERBB2 oncogene and accounts for about 15% of breast cancer cases. Somatic mutation of ERBB2 is an alternative mechanism, by which activation of HER2 signaling can occur. ERBB2 mutation has been associated with invasive lobular breast cancer (ILBC). This study investigates the frequency and phenotype of ILBC harboring mutated ERBB2. The ERBB2 mutation status was determined by next generation sequencing and/or pyrosequencing in n = 106 ILBCs, including n = 86 primary or locally recurrent tumors and n = 20 metastases from visceral organs, soft tissue, or skin. Immunohistochemical characteristics were determined using tissue microarrays. This series was enriched for ILBCs with pleomorphic histology and/or high-risk expression profiles (Oncotype DX, recurrence score RS > 25). Nearly all specimens were E-cadherin-negative (99%), estrogen receptor (ER)-positive (92%), and lacked ERBB2 overexpression (96%). ERBB2 mutations (p.V777L, p.L755S, p.S310F) were identified in 5/106 (5%) cases. ERBB2-mutated cases included 2/86 (2%) primary tumors and 3/20 (15%) metastases (P = 0.045). ERBB2-mutated cases were associated with loss of ER (2/7, 29%, P = 0.035) and histological grade 3 (4/34, 12%, P = 0.023), but not with solid growth (3/31, 10%, P = 0.148) or pleomorphic histology (2/27, 7%, P = 0.599). No ERBB2 mutation was detected in ILBCs with RS > 25 (0/22, 0%). In 10 patients with multiple matched specimens (n = 25), the ERBB2 mutational status was always concordant. In summary, a small subset of ILBCs harbors potentially actionable ERBB2 mutations. In ERBB2-mutated ILBCs, no association with pleomorphic histology was found.

Correction to: Reducing chemotherapy use in clinically high-risk, genomically low-risk pN0 and pN1 early breast cancer patients: five-year data from the prospective, randomised phase 3 West German Study Group (WSG) PlanB trial.

The article Reducing chemotherapy use in clinically high-risk, genomically low-risk pN0 and pN1 early breast cancer patients: five-year data from the prospective, randomised phase 3 West German Study Group (WSG) PlanB trial, written by Ulrike Nitz, Oleg Gluz, Matthias Christgen, Ronald E. Kates, Michael Clemens, Wolfram Malter, Benno Nuding, Bahriye Aktas, Sherko Kuemmel, Toralf Reimer, Andrea Stefek, Fatemeh Lorenz-Salehi, Petra Krabisch, Marianne Just, Doris Augustin, Cornelia Liedtke, Calvin Chao, Steven Shak, Rachel Wuerstlein, Hans H. Kreipe, Nadia Harbeck, was originally published electronically on the publisher's internet portal (currently SpringerLink) on June 29, 2017 without open access.With the author(s)' decision to opt for Open Choice the copyright of the article changed on January 6, 2019 to © The Author(s) 2017 and the article is forthwith distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License ( http://creativecommons.org/licenses/by-nc/4.0/ ), which permits any noncommercial use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, a link is provided to the Creative Commons license and any changes made are indicated. The original article has been corrected.

Lobular carcinoma in situ and invasive lobular breast cancer are characterized by enhanced expression of transcription factor AP-2ß.

Transcription factor AP-2ß (TFAP2B) regulates embryonic organ development and is overexpressed in alveolar rhabdomyosarcoma, a rare childhood malignancy. Gene expression profiling has implicated AP-2ß in breast cancer (BC). This study characterizes AP-2ß expression in the mammary gland and in BC. AP-2ß protein expression was assessed in the normal mammary gland epithelium, in various reactive, metaplastic and pre-invasive neoplastic lesions and in two clinical BC cohorts comprising >2000 patients. BCs from various genetically engineered mouse (GEM) models were also evaluated. Human BC cell lines served as functional models to study siRNA-mediated inhibition of AP-2ß. The normal mammary gland epithelium showed scattered AP-2ß-positive cells in the luminal cell layer. Various reactive and pre-invasive neoplastic lesions, including apocrine metaplasia, usual ductal hyperplasia and lobular carcinoma in situ (LCIS) showed enhanced AP-2ß expression. Cases of ductal carcinoma in situ (DCIS) were more often AP-2ß-negative (P<0.001). In invasive BC cohorts, AP-2ß-positivity was associated with the lobular BC subtype (P<0.001), loss of E-cadherin (P<0.001), a positive estrogen receptor (ER) status (P<0.001), low Ki67 (P<0.001), low/intermediate Oncotype DX recurrence scores (P<0.001), and prolonged event-free survival (P=0.003). BCs from GEM models were all AP-2ß-negative. In human BC cell lines, AP-2ß expression was independent from ER-signaling. SiRNA-mediated inhibition of AP-2ß diminished proliferation of lobular BC cell lines in vitro. In summary, AP-2ß is a new mammary epithelial differentiation marker. Its expression is preferentially retained and enhanced in LCIS and invasive lobular BC and has prognostic implications. Our findings indicate that AP-2ß controls tumor cell proliferation in this slow-growing BC subtype.

Reducing chemotherapy use in clinically high-risk, genomically low-risk pN0 and pN1 early breast cancer patients: five-year data from the prospective, randomised phase 3 West German Study Group (WSG) PlanB trial.

BACKGROUND: The prospective phase 3 PlanB trial used the Oncotype DX® Recurrence Score® (RS) to define a genomically low-risk subset of clinically high-risk pN0-1 early breast cancer (EBC) patients for treatment with adjuvant endocrine therapy (ET) alone. Here, we report five-year data evaluating the prognostic value of RS, Ki-67, and other traditional clinicopathological parameters. METHODS: A central tumour bank was prospectively established within PlanB. Following an early amendment, hormone receptor (HR)+ , pN0-1 RS ≤ 11 patients were recommended to omit chemotherapy. Patients with RS ≥ 12, pN2-3, or HR-negative/HER2-negative disease were randomised to anthracycline-containing or anthracycline-free chemotherapy. Primary endpoint: disease-free survival (DFS). PlanB Clinicaltrials.gov identifier: NCT01049425. FINDINGS: From 2009 to 2011, PlanB enrolled 3198 patients (central tumour bank, n = 3073) with the median age of 56 years, 41.1% pN+, and 32.5% grade 3 EBC. Chemotherapy was omitted in 348/404 (86.1%) eligible RS ≤ 11 patients. After 55 months of median follow-up, five-year DFS in ET-treated RS ≤ 11 patients was 94% (in both pN0 and pN1) versus 94% (RS 12-25) and 84% (RS > 25) in chemotherapy-treated patients (p < 0.001); five-year overall survival (OS) was 99 versus 97% and 93%, respectively (p < 0.001). Nodal status, central/local grade, tumour size, continuous Ki-67, progesterone receptor (PR), IHC4, and RS were univariate prognostic factors for DFS. In a multivariate analysis including all univariate prognostic markers, only pN2-3, central and local grade 3, tumour size >2 cm, and RS, but not IHC4 or Ki-67 were independent adverse factors. If RS was excluded, IHC4 or both Ki-67 and PR entered the model. The impact of RS was particularly pronounced in patients with intermediate Ki-67 (>10%, <40%) tumours. INTERPRETATION: The excellent five-year outcomes in clinically high-risk, genomically low-risk (RS ≤ 11) pN0-1 patients without adjuvant chemotherapy support using RS with standardised pathology for treatment decisions in HR+ HER2-negative EBC. Ki-67 has the potential to support patient selection for genomic testing.

BRCA1-like profile predicts benefit of tandem high dose epirubicin-cyclophospamide-thiotepa in high risk breast cancer patients randomized in the WSG-AM01 trial.

BRCA1 is an important protein in the repair of DNA double strand breaks (DSBs), which are induced by alkylating chemotherapy. A BRCA1-like DNA copy number signature derived from tumors with a BRCA1 mutation is indicative for impaired BRCA1 function and associated with good outcome after high dose (HD) and tandem HD DSB inducing chemotherapy. We investigated whether BRCA1-like status was a predictive biomarker in the WSG AM 01 trial. WSG AM 01 randomized high-risk breast cancer patients to induction (2× epirubicin-cyclophosphamide) followed by tandem HD chemotherapy with epirubicin, cyclophosphamide and thiotepa versus dose dense chemotherapy (4× epirubicin-cyclophospamide followed by 3× cyclophosphamide-methotrexate-5-fluorouracil). We generated copy number profiles for 143 tumors and classified them as being BRCA1-like or non-BRCA1-like. Twenty-six out of 143 patients were BRCA1-like. BRCA1-like status was associated with high grade and triple negative tumors. With regard to event-free-survival, the primary endpoint of the trial, patients with a BRCA1-like tumor had a hazard rate of 0.2, 95% confidence interval (CI): 0.07-0.63, p = 0.006. In the interaction analysis, the combination of BRCA1-like status and HD chemotherapy had a hazard rate of 0.19, 95% CI: 0.067-0.54, p = 0.003. Similar results were observed for overall survival. These findings suggest that BRCA1-like status is a predictor for benefit of tandem HD chemotherapy with epirubicin-thiotepa-cyclophosphamide.

The prognostic impact of age in different molecular subtypes of breast cancer.

Breast cancer is a heterogeneous entity composed of distinct molecular subgroups with different molecular and clinical features. We analyzed the association between molecular breast cancer subgroups, age at diagnosis, and prognosis in a compilation of publicly available gene expression datasets. Affymetrix gene expression data (U133A or U133Plus2.0 arrays) of 4467 breast cancers from 40 datasets were compiled and homogenized. Breast cancer subgroups were defined based on expression of ESR1, PR, HER2, and Ki67. Event-free survival was calculated as recurrence-free survival or distant metastasis-free survival if recurrence-free survival was not available. Young age at diagnosis is associated with higher frequency of triple negative and HER2 subtypes and lower frequency of luminal A breast cancers. The 5-year event-free survival rates of patients aged less than 40, between 40 and 50, and >50 years were 54.3 ± 3.5, 68.5 ± 1.9, and 70.4 ± 1.3 %, respectively. When controlling for breast cancer subtype, we found that age <40 years remained significantly associated with poor prognosis in triple negative breast cancer. The effect was modest in luminal tumors and not found in HER2 subtype. Both subtypes and age retained their significances in multivariate analysis. Association of age at diagnosis with molecular breast cancer subtype contributes to its important role as prognostic factor among patients with breast cancer. Still, within the group of triple negative breast cancer, young age <40 years has a significant prognostic value which was retained in multivariate analysis.

Predictive role of HER2/neu, topoisomerase-II-alpha, and tissue inhibitor of metalloproteinases (TIMP-1) for response to adjuvant taxane-based chemotherapy in patients with intermediate-risk breast cancer: results from the WSG-AGO EC-Doc trial.

Taxane-anthracycline-based adjuvant chemotherapy is standard of care in patients with node-positive breast cancer (BC) but is also associated with severe side effects and significant costs. It is yet unclear, which biomarkers would predict benefit from taxanes and/or general chemoresistance. In this study, we investigate a large cohort of patients with intermediate-risk BC treated within the WSG EC-DOC Trial for the predictive impact of topoisomerase-II-alpha, HER2/neu, and TIMP-1. Tumor tissue was available in a representative cohort of 772 cases of the WSG EC-DOC Trial collective which compared 4xEC-4xDoc versus 6xCEF/CMF. In addition to hormone receptor status and Ki-67, HER2/neu+ and topoisomerase-II-alpha status using fluorescence in situ hybridisation (FISH) and immunohistochemistry, TIMP-1 using immunohistochemistry, and aneuploidy of chromosome 17 using FISH were evaluated and correlated with outcome and taxane benefit. There was significant superiority of EC-Doc over CEF regarding 5-year DFS (90 vs. 80 %, respectively, p = 0.006) particularly in patient subgroups defined by HR+, HER2/neu+, high proliferation (i.e., Ki-67 ≥ 20 %), patient age >50 years old and normal chromosome 17 status, high TIMP-1 and low topoisomerase-II-alpha protein expression. Significant prognostic factors in multivariate analysis were EC-Doc therapy (HR = 0.61; 95 %CI 0.38-0.986), age <50 years old (HR = 1.682; 95 %CI 1.025-2.579), centrally assessed grade 3 (HR = 4.657; 95 %CI 1.809-11.989), and high Ki-67 (HR = 2.232; 95 %CI 1.209-4.121). Interestingly, we observed a significant interaction between treatment arm (EC-Doc vs. CEF) and high topoisomerase-II-alpha protein expression (HR = 0.427; 95 %CI 0.203-0.900) in multivariate interaction analysis. Despite of univariate predictive effect of HER2/neu status among other factors only topoisomerase-II-alpha protein expression was associated with significant benefit from EC-Doc compared to CEF by multivariate interaction analysis.

Arbeitsgemeinschaft Gynäkologische Onkologie Recommendations for the Diagnosis and Treatment of Patients with Early Breast Cancer: Update 2024.

Introduction: Each year the interdisciplinary AGO (Arbeitsgemeinschaft Gynäkologische Onkologie, German Gynecological Oncology Group) Breast Committee on Diagnosis and Treatment of Breast Cancer provides updated state-of-the-art recommendations for early and metastatic breast cancer. Methods: The updated evidence-based treatment recommendations for early and metastatic breast cancer have been released in March 2024. Results and Conclusion: This paper concisely captures the updated recommendations for early breast cancer chapter by chapter.