The 52 samples included 15 positive cases for mutations of BRCA1 gene (BRCA1-mutant cases), 10 positive cases for mutations of BRCA2 gene (BRCA2-mutant cases), 15 cases with evidence of hereditary predisposition to breast cancer but without pathogenic mutations in BRCA1 or BRCA2 genes (BRCAx cases) and 12 cases not eligible for BRCA testing and with negative familial history (sporadic cases). This evidence concerns the gene BRCA1 and breast cancer.