Despite the observed long-term remission in a patient with chronic lymphocytic leukemia using TET2-deficient CAR-Ts, research has shown that biallelic TET2 disruption, coupled with sustained expression of factors like BATF3, can precipitate excessive proliferation in an antigen-independent fashion in CAR-Ts 103, 104. The gene discussed is TET2; the disease is B-cell chronic lymphocytic leukemia.