Compared with female breast cancer (FBC), male breast cancer (MBC) is a rare disease representing less than 1% of all BC. Germ-line mutations of BRCA1 and, mostly, BRCA2 are associated with about 10% of all MBCs. Although rare, MBC remains a substantial cause for morbidity and mortality in men.
Currently, FBC research has been the point of reference for MBC research and the management of MBC is based on management of FBC. MBC shares some similarities with post-menopausal estrogen receptor-positive FBC, however increasing evidence indicates that MBC may be different from FBC.
Recently, transcriptome profiling turned out to be a valuable approach to identify and characterize BC subgroups of biological and clinical relevance. Based on transcriptome profiles, the intrinsic heterogeneity in FBCs sharing the same molecular subtype and/or hormonal receptor status could be dissected. Furthermore, differentially expressed gene pathways between BRCA-positive and BRCA-negative could be identified in FBC.
Here, we plan on exploring the transcriptome profile of BRCA-positive and BRCA-negative MBCs in order to identify specific subgroups of MBC by molecular subtype and/or hormonal receptor status.
Samples and data from the ongoing Italian Multicenter Study on MBC will be used. Breast tumors from BRCA-positive and BRCA-negative MBCs, characterized by extensive clinical-pathologic data, will be investigated using transcriptomic profiling by RNA sequencing.
Characterization of the transcriptional landscape of BRCA-positive and BRCA-negative-MBCs may enable the identification of specific MBC subgroups with biological and clinical relevance and could lead to the definition of subtypes that could provide insight into underlying BRCA pathways. Integration of "omics" data with clinical-pathologic information may provide insights into key molecular MBC classification, which may allow for the identification of novel subgroups of patients that can lead to optimal clinical management.
Due to its rarity, MBC research and patient management are mostly based upon data derived from its largely known female counterpart. It could be that the heterogeneity that characterizes FBC hides underlying molecular pathways that are more evident in MBC. Thus, exploration into pathogenic mechanisms of BC might be facilitated more by MBC, unencumbered by confounding factors that exist in FBC, such as reproductive factors and high frequency of the disease.
Investigation of the molecular profiles of BRCA associated MBCs may help in the identification of specific MBC subgroups with biological and clinical relevance and lead to the characterization of subtypes that could provide insight into underlying BRCA pathways. This knowledge could be also translated to FBC, hence offering a unique opportunity to uncover molecular determinants that are inherent to the disease.
Overall, the findings may allow for the identification of new targets which could then be transferred over to BC patients. In clinical practice, the characterization of specific MBC subgroups could providing useful information for a more appropriate clinical management of MBC patients.