Explanation of FOXO1 clinical significance. FOXO1 is the best-studied member of FOXO subfamily. FOXO1 function has been investigated in the tissues and cells of various genetically modified mice of different disease models such as diabetic complications, cardiomyopathy, and carcinogenesis. FOXO1 has been shown to enhance or diminish the clinical events either based on animal studies or projection from in vitro studies.