Male Breast Cancer: Immunohistochemical Subtypes and Clinical Outcome Characterization

Abstract

Aim: The aim of this study was to assess the molecular subtype profiles of male breast cancer (MBC) and subsequent clinical outcome using a validated 6-marker immunohistochemical panel. Methods: A total of 43 cases of MBC were examined retrospectively using a semiquantitative immunohistochemical analysis of estrogen receptor (ER), progesterone receptor (PR), Ki-67, human epidermal growth factor receptor 2 (Her2), epidermal growth factor receptor and cytokeratin 5/6. Patients were classified into the following categories: luminal A, luminal B, Her2-positive or basal-like subtypes. Results: The median age of patients was 63 years (r: 32–89). The predominant histology was invasive ductal carcinoma (91%). Only 1 patient had advanced breast cancer at diagnosis. Ninety-three percent were ER-positive and 84% were PR-positive. Two patients had tumors that were ER- and PR-negative. The distribution of tumor molecular subtypes was 19 (44%) luminal A, 22 (51%) luminal B and 2 (5%) basal-like. The Her2-positive tumor subtype was not identified. The clinicopathological characteristics did not differ significantly between tumor subtypes A and B. There were no significant differences in 6-year disease-free survival (74 vs. 82%, p = 0.77) or overall survival (74 vs. 82%, p = 0.69) between luminal A and luminal B subtypes, respectively. Conclusion: The most common subtypes in our cohort of MBC were luminal B followed by luminal A, and no differences were found between both tumor subtypes in terms of clinicopathologic characteristics and patient outcome.

Abstract P1-17-02: Male breast carcinoma: A clinicopathological and immunohistochemical characterization study

“…The basal-like subtype is very rare in male breast cancer [7][8][9][10]. Only 2 cases were classified as basal-like subtype in our study.…”

“…As high-cost microarray-based studies are not always feasible, immunohistochemical markers have been used as surrogates for classifying breast cancer [6]. Immunohistochemistry defined subtyping of male breast carcinoma exhibited conflicting results in several studies [7][8][9][10], due to different IHC-based subtyping algorithms. However, only a few studies have examined male breast carcinoma in Chinese population [11,12], and the molecular subtypes remain understudied.…”

Copy number profiling by array comparative genomic hybridization identifies frequently occurring BRCA2‐like male breast cancer

“…In this retrospective study, we analyzed CN profiles of MBC by array CGH, assessed BRCA1 and BRCA2‐like profiles as previously established for FBC, and correlated these with clinicopathological characteristics and CN profiles of ER/HER2 matched FBC. Our cohort, the largest analyzed to date by the highest resolution aCGH so far, seems to be overall comparable to other MBC cohorts regarding ER status (96% positive, literature range 54–100%), PR status (72% positive vs. 50–96%), HER2 status (4% positive vs. 2–56%), Ki67 status (23% high vs. 20–47%, although different cutoffs for high/low Ki67 have been used), p53 positivity (36% vs. 9–58%), intrinsic subtype (luminal A 68% vs. 44–83%, luminal B 25% vs. 10–51%), and histological grade (23% high vs. 3‐85%) (Joshi et al, ; Rayson et al, ; Pich et al, ; Bloom et al, ; Wang‐Rodriguez et al, ; Kwiatkowska et al, ; Muir et al, ; Rudlowski et al, ; Dakin Haché et al, ; Ge et al, ; Kanthan et al, ; Deb et al, ; Ottini et al, ; Sánchez‐Muñoz et al, ; Nilsson et al, ; Yu et al, ).…”

The Effect of Antineoplastic Drugs in a Male Spontaneous Mammary Tumor Model

“…In another study luminal A tumors were 82.8%, luminal B (HR−/HER2+) tumors found in 6.2%, and basal-like (HR−/HER2−) tumors were found in 9.6% of the male breast cancer cohort [19]. Contrary to these, another series reported to have no significant difference between tumor subtypes [20]. These studies show that the distribution of molecular subtypes in male breast cancer varies, but that it is also different compared to the female breast cancer cohorts.…”