STAT3 and ulcerative colitis: Multiple signaling pathways have been implicated in the pathogenesis of ulcerative colitis (UC), including Sphingosine Kinase 1 (SPHK)/Sphingosine‐1‐Phosphate (S1P), AMP‐activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/NLR family pyrin domain‐containing 3 (NLRP3), zonula occludens‐1 (ZO‐1), and signal transducer and activator of transcription 3 (STAT3).