TP53 mutations in breast cancer associated with BRCA1 or BRCA2 germ-line mutations: Distinctive spectrum and structural distribution

Several groups have studied the molecular pathology of inherited breast can cer. By combining several such studies, we show in this study that somatic TP53 abnormalities are more common in breast cancer associated with BRCA1 o r BRCA2 germ-line mutations than in sporadic breast cancers (odds ratio, 2. 8; P = 0.0003). Then, we compared the spectrum of TP53 mutations for breast cancers in the IARC TP53 mutation database with the 82 mutations reported in BRCA1/2-associated breast cancers. The spectrum differed significantly b oth in distribution (P < 1 x 10(-6)) and in base changes (P = 0.025), Mutat ions at A:T bp were more common in BRCA1/2-associated tumors and strand bia s suggesting DNA repair abnormalities was found. Changes were common at TP5 3 codons that are not mutation hotspots, Structural modeling showed that mo st of these p53 non-hotspot amino acids characterized in breast tumors isol ated from patients with deficient BRCA1/2 function are distributed in a reg ion of the protein on the opposite side of the p53 DNA-binding surface. Our results suggest that BRCA1/2 mutations influence the type and distribution of TP53 mutations seen in breast cancer.