CLDN1 and oral cavity squamous cell carcinoma: Moreover, CLDN1 was described to promote mesenchymal transformation in hepatocellular carcinoma (HCC) by upregulating Slug and Zeb1 [55], and to enhance the invasive ability of oral squamous cell carcinoma by promoting the cleavage of laminin-5 gamma2 chains via MMP-2 and membrane-type MMP-1 [56].