CD7 and mantle cell lymphoma: In fact, several cases of lineage switch have been reported post-CAR therapy: chronic lymphocytic leukemia transforming into plasmablastic lymphoma (Evans et al., 2015), mantle cell lymphoma transforming into histiocytic sarcoma (Zhang et al., 2020), and T-ALL transforming into AML after CD7 CAR-T treatment (Aldoss et al., 2023).