Considering the discrepant data on the prevalence of MTAP deficiency and evidence for a clinical importance of MTAP expression in prostate cancer, a preexisting tissue microarray (TMA) containing more than 17,000 prostate cancer specimens with annotated clinical data was analyzed by immunohistochemistry (IHC) for MTAP expression using a previously validated assay [20]. The gene discussed is MTAP; the disease is Familial prostate cancer.