Studies in patients with metastatic prostate cancer have shown that flares peak on bone scintigraphy 6 to 8 weeks after treatment22,23, and as a result of this, the Prostate Cancer Working Group 2 (PCWG2) do not recommend any immediate changes to treatment if there is an increase in bone accumulation using scintigraphy, or an increase in PSA levels within 12 weeks of treatment initiation24. The gene discussed is KLK3; the disease is metastatic prostate carcinoma.