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Objectives. The retinoblastoma (RB) pathway is crucial in the development and progression of many cancers. To better understand the biology of progressive breast cancer (BC), we examined protein expression of the RB pathway in primary BCs and matched axillary lymph node metastases (LM). Methods. Immunohistochemistry was used to evaluate cyclin D1, CDK4/6, RB, phosphorylated RB (pRB), and E2F1 expression in tissue arrays containing cores of 50 primary BCs and matched LM. The number of positive tumor cells and staining intensity were scored. Results. The proteins were localized in the nucleus, while CDK6 was detected in the cytoplasm and CDK4 was found in both. pRB and E2F1 showed higher expression in matched LM than in primary tumors. Expression of these proteins differed significantly by the percentage of positive tumor cells, while proteins in the proximal portion of the RB pathway showed no significant differences. The main path of alteration consisted of high pRB in primary BC, remaining pRB high in the majority of LM, variations occurring in fewer cases. All matched LM of the few primary tumors that had unaltered RB and pRB expression showed changes in RB or pRB expression. Conclusion. Expression of pRB and E2F1 was significantly higher in LM than in primary BC. A majority of cancers with LM showed altered RB or pRB expression, suggesting that proteins downstream in the RB pathway play a critical role in metastatic BC and disease progression. So looking at the RB pathway could be an option for chemotherapy decisions in patients with only few LM. [ABSTRACT FROM AUTHOR]

Introduction: Almost 30% of all women with early-stage breast cancer develop metastases. Treatment of metastatic disease is often based on the immunohistochemical information of the primary tumor, despite possible discordance of the hormone and Her2 receptor status. Objectives: The aim of this study was to compare the receptor status of the primary tumor with the metastasis, and to evaluate for receptor discordance with regard to the molecular subtype, receptor status, and the localization of the metastases. Methods: We retrospectively analyzed the data of all consecutive women with metastatic breast cancer, who underwent treatment at the Medical University Vienna between 2009 and 2016. Associations were calculated using the χ2or Fisher's exact test; years from primary diagnosis to metastatic disease were calculated using the Kaplan-Meier method. Results: We identified 213 metastatic breast cancer patients, of whom 67 (31.5%) showed a discordant receptor status. Out of 32 patients with luminal A subtype, 14 (43.8%) had a switch of at least one receptor; 27 of 53 patients (50.9%) with luminal B subtype and 21 of 32 patients (65.6%) with Her2+ subtype showed receptor discordance; for triple-negative disease, 5 of 19 patients (36.3%) had a switch of at least one receptor. In 63 samples of bone metastases, 13 (20.6%) had discordant estrogen receptor status (p = 0.04). In 55 samples of bone metastases, 35 (63.3%) had discordant Her2 status (p = 0.002). Conclusions: Our data show high rates of receptor discordance in metastatic breast cancer. Apart from the primary tumor, the immunohistochemical receptor status of the metastasis needs to be verified. This can lead to a change in treatment and prognosis. [ABSTRACT FROM AUTHOR]

Germline variations in the BRCA‐1 and BRCA‐2 genes are associated with an increased risk of breast cancer. These variants are found in 5% of all breast cancer cases. Prophylactic mastectomy is the most effective risk‐reducing method and shows high rates of patient satisfaction and acceptance. We established a registry of Austrian BRCA‐1 and BRCA‐2 mutation carriers who had undergone mastectomy for oncologic or prophylactic reasons. Data were collected on the type of operation, complications, and type of reconstructive surgery for patients between 2014 and 2017. The complication rate in patients with nipple‐sparing mastectomy was significantly lower (23.1%) than in those with other types of mastectomies (60.7%; P =.005). In patients with implant‐based breast reconstruction, subpectoral placement was associated with a significantly higher rate of complications than prepectoral placement (P =.025). Median implant volume was 350 cc (range: 155‐650 cc), and a 100‐cc increase was associated with doubling of the odds of a complication (regression coefficient = 0.007); based on this finding, some surgeons may decide on using smaller implants. In summary, we identified significant associations between the risk of complications and surgical characteristics, and found host factors like diabetes, BMI, and smoking among Austrian patients with BRCA‐1 and BRCA‐2 variants. [ABSTRACT FROM AUTHOR]

Background: Even though trastuzumab is an effective therapy in early stage Her-2+ breast cancer, 40–50% of advanced Her-2+ breast cancer patients develop trastuzumab resistance. A potential resistance mechanism is aberrant downstream signal transmission due to loss of phosphatase and tensin homologue (PTEN). This study investigated the relationship between the expression of PTEN and trastuzumab response in Her-2 overexpressing metastatic breast cancer patients. Methods: Between 2000 and 2007, 164 patients with Her-2+ metastatic breast cancer received trastuzumab-based therapy in our institution. We analyzed PTEN status by immunohistochemistry of 115 available tumor tissues and analyzed associations with other histopathological parameters, response rate, progression free survival (PFS) and overall survival (OS) with a median follow-up of 60 months. Results: Eighty patients were PTEN positive (69.6%) and 35 patients PTEN negative (30.4%). We found a significant association of the expression of PTEN and p53 (p = 0.041), while there was no association with grading, hormone receptor status, IGFR or MIB. We found significantly more cases with progressive disease under trastuzumab-based therapy in patients with PTEN positive breast cancers (p = 0.018), while there was no significant correlation with PFS or OS. Conclusion: In Her-2-positive metastatic breast cancers, PTEN positivity was significantly associated with progressive disease, but not with PFS or OS. [ABSTRACT FROM AUTHOR]