Our previous study, showing that 44 % of the histologically benign sampled areas of cancerous prostates contained TMPRSS2-ERG mRNA transcripts in contrast to none of the seven benign tissues of cancer-free prostates [9], led us to hypothesize on TMPRSS2-ERG expression not being limited to carcinoma foci in cancerous prostates. This evidence concerns the gene TMPRSS2 and carcinoma.