Participants undergo blood sample collection. DNA is extracted from these samples for polymorphism analysis of low penetrance cancer susceptibility genes in the following related clinical trials: MREC-SEARCH-CANCER, MREC-SEARCH-PROSTATE, and MREC-SEARCH-BREAST. They may also be used in the analyses of the following related clinical trials: MREC-SEARCH-OVARIAN, MREC-SEARCH-ENDOMETRIAL, MREC-SEARCH-COLORECTAL.