In addition, previous studies have reported a hypoxic environment within keloid tissue.[31,32] In a hypoxic environment, HIF-1α is highly expressed and is an important regulator that helps cells adapt to the hypoxic microenvironment.[33,34] Further studies have reported that the stable accumulation of HIF-1α promotes fibrogenesis in many types of tumors through EMT.[35–38] In a hypoxic/HIF-1α rich environment, VEGF is also highly expressed, as it improves the formation of new vessels in tissue.[31]. This evidence concerns the gene HIF1A and keloid.