Testing of tumor tissue and somatic cells for mutations in BRCA-1 and BRCA-2 for meso with history of ovarian or breast cancer; mutations at 2p16, 3p21.3, 7p22 for history of multiple endocrine cancer; and del(22q11.2) and trisomy 13, 15, 18 or 21 and for peritoneal meso with heart valve defects. Here, BRCA2 is linked to breast cancer.