Inherited rare and common variants in PTCH1 and PTCH2 contributing to the predisposition to reproductive cancers

PTCH1 and PTCH2 are associated with nevoid basal cell carcinoma syndrome and basal cell carcinoma. We determined the prevalence of their common and rare variants in 877 patients with various reproductive cancers and 296 healthy subjects. Using targeted next-generation sequencing, we found significantly statistical associations of the minor alleles at seven common variants of PTCH1 and PTCH2 with a decreased risk of reproductive cancers (P = 9.69 × 10^-12). Among these variants, two haplotype blocks in high linkage disequilibrium were consisted of rs2277184, rs2066829 and rs2236405 sites at PTCH1 and rs3795720, rs11573590 and rs11211040 sites at PTCH2. Single marker and haplotype-based analysis consistently revealed a decreased risk of reproductive cancers especially breast and prostate cancers in the subjects carrying the minor alleles, and on the contrary, an increased risk for major alleles. Healthy control subjects showed a higher rate of rare variants than that of cancer patients (P = 0.017). Notably, two frameshift variants (p.Ser391* and p.Cys101Alafs*48) of PTCH2 with deleterious effects were found in only four cancer patients. Higher frequencies of variants of PTCH genes might have a protective role against the development of reproductive cancers, whereas rare deleterious variants of PTCH2 might predispose a carrier to reproductive cancers.