It is likely that increased angiogenesis in the UV irradiated trigenic mice could be, at least in part, due to increased Angpt1 expression. It remains to be determined whether RXRα directly regulate Angpt1 expression, or whether hypoxia/ altered HIF signaling in the melanoma microenvironment modulates secretion of angiogenic factors and contributes towards enhanced angiogenesis. The gene discussed is RXRA; the disease is melanoma.