In solid tumors, where TSAs are scarce, pairing a context sensor with a killing CAR can improve selectivity: ALPPL2 has emerged as a TSA in ovarian cancer and mesothelioma 132, and embedding ALPPL2 sensing within synNotch circuits limits tonic signaling and favors a memory-like state while subsequently driving CARs against HER2, mesothelin, or MCAM, improving control in preclinical models 133. The gene discussed is ALPG; the disease is mesothelioma.