HIF-1a decreases α5 transcriptional activity in GC Rohwer et al. (2008). PTHrP, ZEB2-SP1, Twist1 and AP-1 increase α5 transcriptional activity in CRC Anderson et al. (2007), Nam et al. (2014), Nam et al. (2015). This evidence concerns the gene HIF1A and colorectal carcinoma.