However, Cldn1 is the major claudin expressed on M2 macrophages during inflammation and/or carcinogenesis and is prominently expressed in response to TGF-β and IL-10 [21], which explains the increased expression levels of Cldn1 in HCC patients and the inseparable correlation observed in all study groups. The gene discussed is TGFB1; the disease is hepatocellular carcinoma.