With the increasing incidence of prostate cancer, identifying common genetic variants that confer risk of the disease is important. Here we report such a variant on chromosome 8q24, a region initially identified through a study of Icelandic families. Allele -8 of the microsatellite DG8S737 was associated with prostate cancer in three case-control series of European ancestry from Iceland, Sweden and the US. The estimated odds ratio (OR) of the allele is 1.62 (P = 2.7 x 10(-11)). About 19% of affected men and 13% of the general population carry at least one copy, yielding a population attributable risk (PAR) of approximately 8%. The association was also replicated in an African American case-control group with a similar OR, in which 41% of affected individuals and 30% of the population are carriers. This leads to a greater estimated PAR (16%) that may contribute to higher incidence of prostate cancer in African American men than in men of European ancestry.

We conducted a genome wide SNP association study on 1,803 Urinary Bladder Cancer (UBC) cases and 34,336 controls from Iceland and the Netherlands and follow up studies in seven additional case control groups (2,165 cases and 3,800 controls). The strongest association was observed with allele T of rs9642880 on chromosome 8q24, 30kb upstream of the c-Myc gene (allele specific OR=1.22; P=9.34×10−12). Approximately 20% of individuals of European ancestry are homozygous for rs9642880 (T) and their estimated risk of developing UBC is 1.49 times that of non-carriers with population attributable risk (PAR) of 17%. No association was observed between UBC and the four 8q24 variants previously associated with prostate, colorectal and breast cancers, nor did rs9642880 associate with any of these three cancers. A weaker signal, but nonetheless of genome wide significance, was captured by rs710521 (A) located near the TP63 gene on chromosome 3q28 (allele specific OR=1.19; P=1. 15× 10−7).

Measuring serum levels of the prostate specific antigen (PSA) is the most common screening method for prostate cancer. However, PSA levels are affected by a number of factors apart from neoplasia. Notably, around 40% of the variability of PSA levels in the general population is accounted for by inherited factors, suggesting that it may be possible to improve both sensitivity and specificity by adjusting test results for genetic effects. In order to search for sequence variants that associate with PSA levels, we performed a genome-wide association study and follow-up analysis using PSA information from 15,757 Icelandic and 454 British men not diagnosed with prostate cancer. Overall, we detected a genome-wide significant association between PSA levels and SNPs at six loci: 5p15.33 (rs2736098), 10q11 (rs10993994), 10q26 (rs10788160), 12q24 (rs11067228), 17q12 (rs4430796), and 19q13.33 (rs17632542 (KLK3: I179T), each with Pcombined < 3×10−10. Among 3,834 men who underwent a biopsy of the prostate, the 10q26, 12q24, and 19q13.33 alleles that associate with high PSA levels are associated with higher probability of a negative biopsy (OR between 1.15 and 1.27). Assessment of association between the 6 loci and prostate cancer risk in 5,325 cases and 41,417 controls from Iceland, the Netherlands, Spain, Romania, and the US showed that the SNPs at 10q26 and 12q24 were exclusively associated with PSA levels, whereas the other 4 loci also were associated with prostate cancer risk. We propose that a personalized PSA cutoff value, based on genotype, should be used when deciding to perform a prostate biopsy.