KLK3 and prostate cancer: At the time of writing, our patient has been on enzalutamide for another 9 months with a sustained PSA response until the last measurement when his serum PSA increased from 2.5 mg/L (at 7 months) to 8.2 mg/L (at 9 months) which is defined as PSA progression according to the Prostate Cancer Working Group Criteria 3 (PCWG3).