Immunohistochemistry was used to analyze the expression of downstream RAS pathway targets in endometrial cancer tissue and nearby non-cancerous endometrium, including phosphoinositide-3-kinase (PIK3R1), plasminogen activator inhibitor-1 (SERPINE1), VEGFA, and transforming growth factor beta 1 (TGFB1). Here, TGFB1 is linked to endometrial cancer.