Gene defects underlying hereditary cancer predisposition syndromes such as alterations in adenomatous polyposis coli (APC), cadherin 1 (CDH1), BRCA1, von Hippel-Lindau tumour suppressor (VHL) and ataxia telangiectasia mutated (ATM) are associated with a high risk to develop tissue-specific cancer types, whereas others, such as DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, PMS1, PMS2) or TP53 are associated with cancers from many different tissues of origin. For each syndrome, associated cancer entities with an at least 4-fold increased risk are indicated. CRC, colo-rectal cancer; GC, gastric cancer; BC, breast cancer; OC, ovarian cancer; PC, pheochromocytoma (adrenal gland tumour); ccRCC, clear cell renal cell carcinoma; LY, lymphoid malignancies; LE, leukaemia; EC, endometrial cancer; STS, soft tissue sarcoma; OS, osteosarcoma; ACC, adrenal cortical carcinoma; GB, glioblastoma.