MUC5AC and periampullary adenocarcinoma: The results suggest that fibronectin may mediate the association between 8 taxa (Alloprevotella, Holdemania, LachnospiraceaeUCG010, Tyzzerella3, Rikenellaceae, Alistipes, Terrisporobacter and Dialister) and periampullary cancer, collagen alpha‐1(I) chain affects Holdemania and LachnospiraceaeUCG010, laminin is related to Rikenellaceae and mucin affects Terrisporobacter and Rikenellaceae.