The molecular genetic make-up of male breast cancer.

Abstract

Male breast cancer (MBC) is extremely rare and accounts for less than 1% of all breast malignancies. Therefore, clinical management of MBC is currently guided by research on the disease in females. In this study, DNA obtained from 45 formalin-fixed paraffin-embedded (FFPE) MBCs with and 90 MBCs (52 FFPE and 38 fresh-frozen) without matched normal tissues was subjected to massively parallel sequencing targeting all exons of 1943 cancer-related genes. The landscape of mutations and copy number alterations was compared to that of publicly available estrogen receptor (ER)-positive female breast cancers (smFBCs) and correlated to prognosis. From the 135 MBCs, 90% showed ductal histology, 96% were ER-positive, 66% were progesterone receptor (PR)-positive, and 2% HER2-positive, resulting in 50, 46 and 4% luminal A-like, luminal B-like and basal-like cases, respectively. Five patients had Klinefelter syndrome (4%) and 11% of patients harbored pathogenic BRCA2 germline mutations. The genomic landscape of MBC to some extent recapitulated that of smFBC, with recurrent PIK3CA (36%) and GATA3 (15%) somatic mutations, and with 40% of the most frequently amplified genes overlapping between both sexes. TP53 (3%) somatic mutations were significantly less frequent in MBC compared to smFBC, whereas somatic mutations in genes regulating chromatin function and homologous recombination deficiency-related signatures were more prevalent. MDM2 amplifications were frequent (13%), correlated with protein overexpression (P = 0.001) and predicted poor outcome (P = 0.007). In conclusion, despite similarities in the genomic landscape between MBC and smFBC, MBC is a molecularly unique and heterogeneous disease requiring its own clinical trials and treatment guidelines.

• Authors: Cathy B Moelans, Joep de Ligt, Petra van der Groep, Pjotr Prins, Nicolle J M Besselink, Marlous Hoogstraat, Natalie D Ter Hoeve, Miangela M Lacle, Robert Kornegoor, Carmen C van der Pol, Wendy W J de Leng, Ellis Barbé, Bert van der Vegt, John Martens, Peter Bult, Vincent T H B M Smit, Marco J Koudijs, Isaac J Nijman, Emile E Voest, Pier Selenica, Britta Weigelt, Jorge S Reis-Filho, Elsken van der Wall, Edwin Cuppen, Paul J van Diest
• Journal: Endocrine-related cancer (Endocr Relat Cancer) Vol. 26 Issue 10 Pg. 779-794 (10 2019) ISSN: 1479-6821 [Electronic] England
• PMID: 31340200 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers, Tumor

Topics

• Adult
• Aged
• Aged, 80 and over
• Biomarkers, Tumor (genetics)
• Breast Neoplasms (genetics)
• Breast Neoplasms, Male (genetics, pathology)
• DNA Copy Number Variations
• Female
• Gene Amplification
• Genome, Human (genetics)
• Humans
• Male
• Middle Aged
• Mutation
• Oncogenes (genetics)
• Prognosis