BRCA1 and cancer: In fact, the analysis of only 4 PCR fragments (1806C>T, exon 5 (300T>G, 300T>A), 5382insC in the BRCA1 gene and IVS16-2A>G in the BRCA2 gene) would lead to the identification of the cancer predisposing mutations in 67% of the BRCA1/2 mutation-positive families.