Sarah L. Kerns, Ph.D., from the Mount Sinai School of Medicine in New York City, and colleagues conducted a two-stage genome-wide association study to identify SNPs associated with development of ED among radiotherapy-treated prostate cancer patients. Participants were randomly divided into a stage I discovery cohort (132 cases and 103 controls), which was genotyped using Affymetrix 6.0 genome-wide arrays, and a stage II replication cohort (128 cases and 102 controls), which was genotyped using Illumina iSelect custom SNP arrays.

The researchers found that 12 SNPs identified in the discovery cohort and validated in the replication cohort correlated significantly with development of post-radiotherapy ED. The 12 SNPs were located in or near genes involved in erectile function or other normal cellular functions (adhesion and signaling). In the pooled cohort, the odds ratios for these SNPs ranged from 1.6 to 5.6. The cumulative number of SNP risk alleles an individual possessed was significantly associated with ED status. There was a significant increase in the odds for developing ED by a factor of 2.2 for each one-allele increase in cumulative SNP score. The sensitivity was 84 percent and specificity was 75 percent for the cumulative SNP score model's ability to predict the development of ED at the radiotherapy planning stage.

"This genome-wide association study identified a set of SNPs that are associated with development of ED following radiotherapy," the authors write.

Abstract
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