To search for an association between the presence or absence of the deletions in KLK9 and KLK15 and prostate cancer (PC), DNA isolated from 266 men with evidence of PC at prostate biopsy and 401 men with no evidence of PC at biopsy (see Table S1 for a summary of clinical data) were analyzed using short deletion-specific PCR assays. This evidence concerns the gene KLK9 and pachyonychia congenita.