Colorectal carcinomas without a family history are considered to be "sporadic" carcinomas, however, also have a genetic basis. Within the hereditary forms there are 15-50% of patients without a family history being carriers of de novo germline mutations. In addition, non-pathogenic polymorphisms in these tumorsyndrome-genes as well as in genes involved in the carcinogen metabolism (GST, NAT, CYP, MTHFR) are associated with an increased or decreased colorectal cancer risk. Identification of these genetic risk factors will enable individually tailored surveillance and recommendations for prophylaxis as well as individually tailored treatment.