Genome-wide association study identifies novel alleles associated with risk of cutaneous basal cell carcinoma and squamous cell carcinoma.

We conducted a genome-wide association study on cutaneous basal cell carcinoma (BCC) among 2045 cases and 6013 controls of European ancestry, with follow-up replication in 1426 cases and 4845 controls. A non-synonymous SNP in the MC1R gene (rs1805007 encoding Arg151Cys substitution), a previously well-documented pigmentation gene, showed the strongest association with BCC risk in the discovery set (rs1805007[T]: OR (95% CI) for combined discovery set and replication set [1.55 (1.45-1.66); P= 4.3 × 10(-17)]. We identified that an SNP rs12210050 at 6p25 near the EXOC2 gene was associated with an increased risk of BCC [rs12210050[T]: combined OR (95% CI), 1.24 (1.17-1.31); P= 9.9 × 10(-10)]. In the locus on 13q32 near the UBAC2 gene encoding ubiquitin-associated domain-containing protein 2, we also identified a variant conferring susceptibility to BCC [rs7335046 [G]; combined OR (95% CI), 1.26 (1.18-1.34); P= 2.9 × 10(-8)]. We further evaluated the associations of these two novel SNPs (rs12210050 and rs7335046) with squamous cell carcinoma (SCC) risk as well as melanoma risk. We found that both variants, rs12210050[T] [OR (95% CI), 1.35 (1.16-1.57); P= 7.6 × 10(-5)] and rs7335046 [G] [OR (95% CI), 1.21 (1.02-1.44); P= 0.03], were associated with an increased risk of SCC. These two variants were not associated with melanoma risk. We conclude that 6p25 and 13q32 are novel loci conferring susceptibility to non-melanoma skin cancer.