Fucoidan intake has been found to restore the microbiota and intestinal barrier function by regulating tight junction-associated proteins (ZO-1, occludin, claudin-1, and claudin-8) and the MAPK signaling pathway in a 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast cancer rat model [30]. The gene discussed is CLDN8; the disease is breast cancer.