Based on the activation of the aryl hydrocarbon receptor (AhR) signaling pathway, NIN increases the expression of the Wnt/β-catenin signaling pathway inhibitor Rnf43, inhibits the expression of nonphosphorylated β-catenin, and reduces the level of the pathway downstream target gene Axin2, which in turn inhibits the Wnt/β-catenin signaling pathway and inhibits the expression of Lgr5, a stem cell gene of colorectal cancer (CAC). The gene discussed is AXIN2; the disease is colorectal cancer.