The intronic long‐noncoding RNA (lncRNA) PCA3 is a specific marker of prostate cancer that acts as a trans‐dominant negative oncogene to down‐regulate the tumor suppressor gene PRUNE2. The unusual genomic organization and sequence of PCA3 leads us to hypothesize that it was introduced into the human genome by an as‐yet undefined oncogenic virus. The gene discussed is PCA3; the disease is prostate carcinoma.