APOE and thromboangiitis obliterans: Previous research has shown that many genes and signal transduction pathways, such as insulin-like growth factor-1 receptor, FABP4/5, APOE, PPARG and ADIPOQ, PI3K Akt signal transduction, cAMP signal transduction, AGE-RAGE signal, and Wnt signal pathway, are involved in the adipogenesis of TAO patients [40, 41].