Transmembrane Protease, Serine 13 (TMPRSS13, also known as Mosaic Serine Protease Large-Form (MSPL)), a TTSP that belongs to the hepsin/TMPRSS subfamily, has recently been implicated as a pro-oncogenic protease in both breast and colorectal cancers (25, 26). Here, TMPRSS13 is linked to colorectal cancer.