In addition to FAPα (EC=3.4.21), this S9b serine peptidase family includes dipeptidyl peptidase 4 (DPP4, also termed CD26, which is identical to FAPβ, EC=3.4.14.5), dipeptidyl aminopeptidase-like protein 6 (also named DPPX or DPP6), DPP8 (EC=3.4.14.5), DPP9 (EC=3.4.14.5) and DPP10, and has been implicated in diabetes, cancer and inflammatory diseases (45–47) (additional information is available at: http://www.uniprot.org; http://enzyme.expasy.org). This evidence concerns the gene DPP4 and diabetes mellitus.