JAK1 and hepatocellular carcinoma: ↓ MASLD-HCC formation in two mouse models; ↑ heathy gut microbiome composition; ↑ gut barrier function. Mechanistically, B. pseudolongum-produced acetate entered the portal vein to reach to the liver and bind to G coupled-protein receptor 43 (GPR43) on hepatocytes. GPR43 activation suppressed the IL-6/JAK1/STAT3 signaling pathway, thereby preventing MASLD-HCC progression