FAS and intestinal disorder: STAT1 inhibits the signal transduction process of IFN, upregulates the expression of caspase 1 and Fas/FasL, inhibits growth, stimulates apoptosis, and promotes intestinal ulcers.[54] The activation of STAT3 in the mucosal cells of the intestine of patients can upregulate Bcl-2 expression, downregulate Bax expression, resist apoptosis, and promote the proliferation of cells.