A candidate gene approach within the susceptibility region PCaP on 1q42.2-43 excludes deleterious mutations of the PCTA-1 gene to be responsible for hereditary prostate cancer

Objective: The Prostate Carcinoma Tumor Antigen-1 (PCTA-1) is located at the prostate cancer susceptibility locus on chromosome 1q42.2-43 (PCaP). In this candidate gene approach, we searched for deleterious mutations within the PCTA-1 gene and its promoter. Materials and Methods: Seventy-seven familial prostate cancer cases from 36 German and French pedigrees were screened for germline mutations in the PCTA-1 gene using enzymatic mutation detection (EMD). Putative missense mutations were genotyped by RPLP and ddNTP primer extension assays in 88 controls to assess allele frequencies and haplotypes. Results: Several sequence variants were found but none of the findings indicated a deleterious mutation. Three affected brothers showed an intronic variation, which may interfere with correct splicing. Four non-conservative SNPs were characterized, coding for the amino acid alterations Y19F, C36R, V56M and S184R. All exchanges were found in controls with common allelic frequencies of at least 28%. Haplotype definition including six SNPs within the PCTA-1 gene revealed a complete linkage disequilibrium. Low haplotype diversity leads to a predominance of only two peptide variants of the PCTA-1 protein, coded by 95% of all chromosomes. Conclusions: PCTA-1 is not a classical high risk gene with deleterious mutations predisposing to hereditary prostate cancer. Its contribution to prostate cancer susceptibility as a low risk factor in sporadic disease has to be assessed in larger samples by association studies.