Epigenetic regulation and, in particular, DNA methyl- ation have been linked to the underlying genetic sequence. DNA methylation quantitative trait loci (meQTL) have been identified through significant associations between the genetic and epigenetic codes in physiological and pathological contexts. We propose that interrogating the interplay between polymorphic alleles and DNA methylation is a power- ful method for improving our interpretation of risk alleles identified in genome-wide association studies that otherwise lack mechanistic explanation. We integrated patient cancer risk genotype data and genome-scale DNA methylation profiles of 3,649 pri- mary human tumors, representing 13 solid cancer types. We provide a comprehensive meQTL catalog containing DNA methylation associations for 21% of interrogated cancer risk polymorphisms. Differen- tially methylated loci harbor previously reported and as-yet-unidentified cancer genes. We suggest that such regulation at the DNA level can provide a considerable amount of new information about the biology of cancer-risk alleles.