Various PET response criteria were used in the included studies: among them, the most widely evaluated was PSMA tumor volume (PSMA-TV, selected as representative PSMA PET response evaluation criterion for meta-analytical purposes in studies that provided results for multiple criteria), followed by SUVmax, summed SUVmean, and total lesion PSMA (TL-PSMA, which is a product of PSMA-TV and SUVmean of each lesion) with a threshold of PR, SD, PD as −30, and +30% changes suggested by PERCIST 1.0 classification. The gene discussed is FOLH1; the disease is neoplasm.