Population-based risk assessment for other cancers in relatives of hereditary prostate cancer (HPC) cases

BACKGROUND. To identify associations of other cancers with hereditary prostate cancer (HPC) we estimated relative risks (RRs) of 36 different cancers in relatives of prostate cancer cases in the Utah Population Data Base (UPDB), which combines genealogical and cancer data for Utah. METHODS. We utilized known genetic relationships between prostate cancer cases and their relatives with cancer, combined with age- and sex-specific cancer rates calculated internally from the UPDB, to estimate RRs for cancer in relatives of prostate cancer cases. RESULTS. Multiple other cancers were observed in excess in both first- and second-degree relatives of HPC cases including colon cancer, non-Hodgkins lymphoma, multiple myeloma, rectal cancer, cancer of the gallbladder, and melanoma (skin). CONCLUSIONS. This analysis supports the existence of heritable prostate cancer syndromes that include other cancers. We hypothesize that the study of homogeneous pedigrees cosegregating prostate cancer and another cancer could allow more straightforward localization and identification of the gene(s) responsible.