APAF1 and colorectal cancer: For example, under hypoxia, HIF upregulates the expression level of both miR-675-5p, which targets the 3′-UTR region of the caspase-3 mRNA, and miR-27a, which targets the mRNA of APAF1 (apoptotic protease activating factor 1), the major component of apoptosome, and it enhances 5-FU resistance in colorectal cancer cells and paclitaxel resistance in ovarian cancer in vitro.