A genome-wide linkage study of lethal prostate cancer predisposition gene in a set of high-risk pedigrees.

159 Background: Using the unique Utah genealogical resource that links 12 generations of genealogy data to a statewide cancer registry from 1966 and statewide death certificates from 1904 we have identified a set of high-risk prostate cancer pedigrees with multiple cases having died from prostate cancer. Methods: Clusters of prostate cancer cases descended from a common ancestor, among whose descendants is observed a statistical excess of prostate cancer (high-risk prostate cancer pedigrees) were recruited and sampled. Pedigrees with 4 or more cases dying from prostate cancer (as evidenced by inclusion as a cause of death on a Utah death certificate) were genotyped with 720k high-density SNPs across the genome. Linkage analysis with markers not in linkage disequilibrium was performed to identify regions hypothesized to contain a prostate cancer predisposition gene. Results: A single extended Utah high-risk prostate cancer pedigree including 6 distantly related sampled prostate cancer cases who went on to die as a result of their cancer showed significant evidence for linkage at chromosome arm 4q24 (LOD score = +3.28), with 5 of the 6 cases having inherited the same region of chromosome 4 from a common ancestor. Conclusions: The inability of association studies to identify prostate cancer predisposition genes has returned focus to linkage studies of highly informative high-risk pedigrees, which provide power for identifying and localizing regions of interest for predisposition genes. A focus on only those cases who are members of high-risk prostate cancer pedigrees, who also went on to die as a result of their prostate cancer, has resulted in the identification of evidence for a prostate cancer predisposition gene on chromosome arm 4q24, confirming a previous GWAS that reported association with prostate-cancer-specific-survival (Pomerantz MM et al., 2011) in this region harboring TET2 (a tumor suppressor gene involved in pathogenesis of acute myeloid leukemia, myelodysplastic syndrome, and myeloproliferative neoplasms), and PP2A (implicated in androgen receptor regulation in prostate cancer cell lines).