Interestingly, in vitro and in vivo studies identified HIF-1α-dependent strong upregulation of DPP4 mRNA expression under hypoxia growth in cancer cell types including smooth muscle cells, adipocytes and ovarian cells, and the increased protein levels led to its proteolytic shedding from the cell surface in an inactivated form mediated by at least MMP10 and MMP13 [129,130,131]. This evidence concerns the gene DPP4 and cancer.