Although our anti-CD26 novel mAb KU44.13A did not show any effect on cell proliferation or migration on the panel of cell lines evaluated in this study, treatment with other anti-CD26 monoclonal antibodies have shown to reduce tumour growth in vitro and in vivo and improve survival in malignant mesothelioma, renal cell carcinoma and anaplastic large cell T-cell lymphoma46–49. The gene discussed is DPP4; the disease is malignant mesothelioma.