FOLH1 and metastatic neoplasm: In the last decade, Prostate Specific Membrane Antigen (PSMA), a transmembrane protein with a significantly increased expression in PCa cells, has gained particular attention as a radiotracer for positron emission tomography (PET) imaging in PCa, in view of its better sensitivity and specificity in detecting of metastatic disease, compared to conventional imaging, also at low PSA values [4,5,6].