Even if no tumour could be detected at follow-up after 2 yr, the detection rates of PI-RADS category 3 in the PROBASE study in young men with PSA ≥3 ng/ml raise the question whether there are also (undetected) PC in PI-RADS 3 cases with PSA below 3 ng/ml. The gene discussed is KLK3; the disease is neoplasm.