Markedly downregulated claudin 2 and claudin 4 expression in human hepatocellular carcinoma

Background: Claudins (1–18) are integral membrane proteins recently identified as components of tight junction strands. Aim: The objective was to characterize the expression of claudin 1–5, 7 in human HCCs and liver metastases compared to corresponding nontumorous and normal liver samples. Material and methods: 12 human HCC and 12 colon metastasis samples were examined by real-time RT-PCR for expression of claudin 1–5 and 7. Relative quantification was utilized using GAPDH as internal control. The HCC samples did not show nuclear staining for beta-catenin indicating activation of the wnt pathway. Results: Claudi…