Reviewing the literature, most authors have reported PSA decline ≥ 50% or any PSA decline 2 weeks to 3 months after the first or last cycle of [177Lu]Lu-PSMA RLT, based on Prostate Cancer Clinical Trial Working Group criteria [21, 41, 42], and have correlated the data with survival and potentially predictive factors [4, 20, 21, 30]. The gene discussed is KLK3; the disease is prostate cancer.