In terms of hormone receptors, 80.5% (62/77) of patients with MBC were estrogen receptor positive, 75.3% (58/77) of patients were progesterone receptor positive, and only 6.5% (5/77) of patients were HER2 overexpressing.
Not only the estrogen receptor (ER), but also other steroid hormone receptors, including the androgen receptor (AR) and progesterone receptor (PgR) are expressed in MBC.
The aim of this study was to explore the characteristics and prognostic information of estrogen receptor-positive/progesterone receptor-negative (ER+/PR-) male breast cancer.
Body mass index (P = .023) and DACH1 (P = .034) were correlated with MBC prognosis, whereas the expression of AR (P = .049), SIX1 (P = .048), surgery (P < .001), and chemotherapy (P = .001) were important for FBC in addition to already known factors: tumor size and location, TNM stage (lymph nodes and organ metastasis), radiotherapy, and ER and human epidermalgrowth factor receptor-2 (HER2) expression.
Somatic mutations and gene amplification were found only in BRCA1/2 mutation negative MBCs.Significant associations emerged between EGFR amplification and large tumor size (T4), ER-negative and HER2-positive status, between CCND1 amplification and HER2-positive and MIB1-positive status, and between ESR1 deletion and ER-negative status.Our results show that amplification of targetable oncogenes is frequent in BRCA1/2 mutation negative MBCs and may identify MBC subsets characterized by aggressive phenotype that may benefit from potential targeted therapeutic approaches.
Male breast cancer is a hormone-driven disease that often expresses the estrogen receptor, and antiestrogen therapy represents the mainstay of treatment.
The pattern of gains and losses in estrogen receptor positive (ER+) MBC was largely similar to ER+ FBC, except for gains on chromosome X in MBC, which were uncommon in FBC.
Overall, our data, based on a large and well-characterized MBC series, support the hypothesis that common low-penetrance BC susceptibility alleles play a role in MBC susceptibility and, interestingly, indicate that ESR1 is associated with a distinct tumor subtype defined by ER-negative status.
In this study, gene expression profiles of 37 estrogen receptor positive (ER+) MBC specimens were compared to that of 53 ER+ Female Breast Cancer (FBC) samples similar for clinical and patho-biological features.