EPAS1 and digestive system cancer: HIF-2α is frequently detected in most types of solid tumors, including head and neck, renal, bladder, glial, breast, ovarian, prostate and renal cancers.14, 15, 25, 28, 50, 51, 52, 53 An increasing number of studies reporting HIF-2 in the context of digestive system cancer have emerged in recent years and conveyed that this protein plays important roles in digestive system cancers.