Notably, upregulated expression of immune checkpoint markers, such as cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and PD-1, was found within CD4+ T cells, highlighting the involvement of immunodeficiency in cancer cachexia.303 The engineered rimiducid-inducible MyD88- and CD40-driven chimeric antigen receptor (CAR)-T cells elicited antitumor responses, but these CAR-T cells also caused cachexia in mice through dose-dependent weight loss. The gene discussed is CTLA4; the disease is cancer.