Carbone et al. examined 67 human T-cell Non-Hodgkin’s lymphomas and leukemias and found that CD26 expression was exclusive to aggressive pathologies, such as T-cell lymphoblastic lymphoma (LBL)/T-cell acute lymphoblastic leukemia (ALL) and T-cell CD30+ anaplastic large cell (ALC) lymphomas. This evidence concerns the gene DPP4 and T-cell non-Hodgkin lymphoma.