CARs targeting the B-cell antigen CD19, have shown dramatic results in clinical trials for a number of hematologic malignancies ((acute lymphoblastic leukemia (ALL), non-Hodgkin lymphoma (NHL), and chronic lymphocytic leukemia (CLL)) [30,31,32,33], and have provided the “proof of principle” rationale for CAR T cell development in a variety of solid tumors, including MPM. The gene discussed is CD19; the disease is B-cell chronic lymphocytic leukemia.