PV in 10 PDAC patients with multiple primary tumors affected 3 × BRCA1 and 4 × BRCA2 (all had also developed breast and/or ovarian cancer), 1 × PMS2 and 1 × MLH1/MSH6 (both developed colon cancer), and 1 × CDKN2A (diagnosed with melanoma). This evidence concerns the gene BRCA1 and colonic neoplasm.