For example, a controlled study showed that males with a shorter prostate-specific antigen doubling time (PSADT) have higher risks of developing bone metastases or death and that denosumab treatment improved bone metastasis-free survival (BMSF) in males with a shorter PSADT (Smith et al., 2013) and had a more significant treatment effect in males at higher risk of progression. Here, KLK3 is linked to bone metastasis.