Anna Sara Navazio

Novel and known genetic variants for male breast cancer risk at 8q24.21, 9p21.3, 11q13.3 and 14q24.1: Results from a multicenter study in Italy

Increasing evidence indicates that common genetic variants may contribute to the heritable risk of breast cancer (BC). In this study, we investigated whether single nucleotide polymorphisms (SNPs), within the 8q24.21 multi-cancer susceptibility region and within BC-associated loci widespread in the genome, may influence the risk of BC in men, and whether they may be associated with specific clinical-pathologic characteristics of male BC (MBC). In the frame of the ongoing Italian Multicenter Study on MBC, we performed a case-control study on 386 MBC cases, including 50 BRCA1/2 mutation carriers, and 1105 healthy male controls, including 197 unaffected BRCA1/2 mutation carriers. All 1491 subjects were genotyped by Sequenom iPLEX technology for a total of 29 susceptibility SNPs. By logistic regression models, we found a significant association with MBC risk for five SNPs: rs1562430 (p=0.002) and rs445114 (p=0.026) both within the 8q24.21 region; rs1011970/9p21.3 (p=0.011), rs614367/11q13.3 (p=0.016) and rs1314913/14q24.1 (p<0.0001). Differences in the distribution of rs614367/11q13.3 genotypes according to oestrogen receptor (ER) status (p=0.006), and of rs1011970/9p21.3 genotypes according to human epidermal growth factor receptor 2 (HER2) status (p=0.002) emerged. Association of rs1011970/9p21.3 risk genotype with HER2+MBC was confirmed by a multivariate analysis. rs1314913/14q24.1 was associated with increased MBC risk in analyses restricted to male BRCA1/2 mutation carriers (p=0.041). In conclusion, we provided the first evidence that the 8q24.21 region is associated with MBC risk. Furthermore, we showed that the SNPs rs1562430/8q24.21 and rs1314913/14q24.1 strongly influence BC risk in men and suggested that the SNP rs1314913/14q24.1 may act as a risk modifier locus in male BRCA1/2 mutation carriers.

SULT1A1 gene deletion in BRCA2-associated male breast cancer: a link between genes and environmental exposures?

SULT1A1, a member of sulfotransferase superfamily, is a drug and hormone metabolizing enzyme involved in the metabolism of a variety of potential mammary carcinogens of endogenous and exogenous origin. Interestingly, the metabolic activity of SULT1A1 can be affected by variations in gene copy number. Male Breast Cancer (MBC) is a rare disease and less investigated disease compared to female BC (FBC). As in FBC, the concurrent effects of genetic risk factors, particularly BRCA2 mutations, increased exposure to estrogens and environmental carcinogens play a relevant role in MBC. By quantitative real‐time PCR with TaqMan probes, we investigated the presence of SULT1A1 gene copy number variations (CNVs) in a series of 72 MBCs. SULT1A1 gene deletion was observed in 10 of the 72 MBCs (13.9%). In a multivariate analysis association between BRCA2 mutation and SULT1A1 gene deletion emerged (p = 0.0005). Based on the evidence that the level of SULT1A1 enzyme activity is correlated with CNV, our data suggest that in male breast tumors SULT1A1 activity may be decreased. Thus, it can be hypothesized that in a proportion of MBCs, particularly in BRCA2‐associated MBCs, the level of estrogens and environmental carcinogens exposure might be increased suggesting a link between gene and environmental exposure in the pathogenesis of MBC.

Whole-exome sequencing and targeted gene sequencing provide insights into the role of PALB2 as a male breast cancer susceptibility gene

Male breast cancer (MBC) is a rare disease whose etiology appears to be largely associated with genetic factors. BRCA1 and BRCA2 mutations account for about 10% of all MBC cases. Thus, a fraction of MBC cases are expected to be due to genetic factors not yet identified. To further explain the genetic susceptibility for MBC, whole‐exome sequencing (WES) and targeted gene sequencing were applied to high‐risk, BRCA1/2 mutation–negative MBC cases.

Mutational profiling in melanocytic tumors: multiple somatic mutations and clinical implications.

In this study, we analyzed multiple somatic mutations in 10 genes relevant in melanoma tumorigenesis and targeted therapies. Overall, 45% of the tumors showed mutations and, in particular, 33% had multiple mutations. Based on our results, we conclude that the assessment of mutation status of multiple genes, including CDKN2A, could provide a genetic profile that can be useful as a prognostic and therapeutic marker in melanocytic tumors.

Somatic alterations of targetable oncogenes are frequently observed in BRCA1/2 mutation negative male breast cancers

Male breast cancer (MBC) is a rare disease. Due to its rarity, MBC research and clinical approach are mostly based upon data derived from its largely known female counterpart. We aimed at investigating whether MBC cases harbor somatic alterations of genes known as prognostic biomarkers and molecular therapeutic targets in female breast cancer. We examined 103 MBC cases, all characterized for germ-line BRCA1/2 mutations, for somatic alterations in PIK3CA, EGFR, ESR1 and CCND1 genes. Pathogenic mutations of PIK3CA were detected in 2% of MBCs. No pathogenic mutations were identified in ESR1 and EGFR. Gene copy number variations (CNVs) analysis showed amplification of PIK3CA in 8.1%, EGFR in 6.8% and CCND1 in 16% of MBCs, whereas deletion of ESR1 was detected in 15% of MBCs. 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.