Interestingly, CD4+ T cells specific for immunoglobulin-derived neoantigens in mantle cell lymphoma (MCL) were shown to express granzyme B and possess cytolytic function against autologous tumor cells following their engagement and expansion (14, 15), as previously described for granzyme B+ tumor-reactive CD4+ T cells in solid cancer (32). The gene discussed is CD4; the disease is mantle cell lymphoma.