In accordance with these findings, despite a profound increase in expansion capacity, PRDM1 KO CAR T-cells minimally enhanced antitumor activity over control CAR T-cells in xenogeneic murine models of prostate cancer and aggressive B-cell leukemia, and ultimately became progressively dysfunctional due to exacerbated loss of effector activity. The gene discussed is PRDM1; the disease is prostate cancer.