However, a commercially available assay combining serum PSA with urinary PCA3 and the urinary transmembrane protease, serine 2:v-ets erythroblastosis virus E26 oncogene homolog (TMPRSS2:ERG fusion) provides a 90% specificity and 80% sensitivity in diagnosing PCa (25). The gene discussed is PCA3; the disease is posterior cortical atrophy.