FOLR1 and cancer: Based on these clinical trial data and the advances made with biAb engineering (36), FOLR1-targeting T-cell engaging biAbs, which were among the first clinically translated biAbs generated by hybrid hybridoma technology and limited by human anti-mouse antibodies in cancer patients (37), warrant renewed preclinical and clinical investigations as potent and safe alternative treatment modalities, possibly in combination with immune checkpoint inhibitors to overcome T-cell dysfunction in solid malignancies (38).