FOLH1 and cancer: Based on the presented/reviewed data, we consider that the scFvD2B, due to its versatility and robustness, seems to: (i) overcome some problems observed with other scFvs, very often relatively unstable and prone to form aggregates; (ii) have sufficient tumor-to-background ratios for targeting and imaging PSMA-expressing cancer; (iii) significantly redirect immune killing cells to PSMA-positive tumors when inserted in second-generation CAR-T or NK-92/CAR cells.