Association between germline variation in the FHIT gene and prostate cancer in Caucasians and African Americans.

Many studies have established that loss of heterozygosity and/or altered expression of the fragile histidine triad (FHIT) gene is a common event in a number of tumor types including prostate carcinoma. Encompassing the most active fragile site in the human genome, FRA3B, FHIT has become the model fragile site-associated tumor suppressor gene. In a recent study, linkage and association between germline genetic variation in FHIT (specifically single nucleotide polymorphism rs760317) and prostate cancer were reported. We sought to confirm this finding in two independent samples: (a) a family-based sample of 817 men with (n = 434) and without (n = 383) prostate cancer from 323 Caucasian families, and (b) a community-based case-control sample of African American men with (n = 133) and without (n = 342) prostate cancer. Using a family-based association test, rs760317 was associated with prostate cancer in Caucasians (P = 0.031), with a reduction in the risk of prostate cancer among carriers of the minor allele (odds ratio, 0.66; 95% confidence interval, 0.42-1.04; P = 0.074). African American carriers experienced a similar risk reduction (odds ratio, 0.63; 95% confidence interval, 0.42-0.96; P = 0.032). These results are remarkably consistent across ethnic samples but are in opposition to results from the original study, which showed an association between the minor allele of rs760317 and an increased risk of prostate cancer. Taken together, the consistently significant but flipped association between single nucleotide polymorphism rs760317 and prostate cancer in three independent samples suggests that rs760317 may be in linkage disequilibrium with one or more prostate cancer susceptibility variants in or near FHIT.