Overexpression of Tumor-Associated Trypsin Inhibitor (SPINK1/TATI) in Hepatitis C-Associated Hepatocellular Carcinoma: Potential Implications for Viral Hepatocarcinogenesis

Background: The molecular pathomechanisms leading to hepatitis C virus (HCV)-induced hepatocarcinogenesis remain unclear. This study investigated the molecular pathways and key genes underlying HCV-positive hepatocellular carcinoma (HCC) using gene expression profiling. Methods: Oligonucleotide arrays (Affymetrix HU133A) were used to determine and compare the tissue-specific gene expression profiles in 39 cases of HCV-positive or -negative HCC and non-malignant liver tissue. The expression values of the most overexpressed genes were validated by real-time polymerase chain reaction (RT-PCR). Results: 837 genes or expressed sequence tags (ESTs) were significantly differently expressed in HCV-positive HCC versus healthy tissue: 414 were upregulated and 423 were downregulated (p < 0.05; > 2-fold change in ≥ 70% of the samples). A specific gene expression profile for HCV-positive HCC was obtained using 2-dimensional cluster analysis and was confirmed using supervised neuronal network modeling. The most consistently overexpressed gene coded for serine protease inhibitor Kazal-type 1 (SPINK1)/tumor-associated trypsin inhibitor (TATI) (median fold change, 19.7; significantly overexpressed in 90% of the samples). SPINK1/TATI was coregulated with matrix metalloproteinases (MMPs) and their natural inhibitors (tissue inhibitors of metalloproteinases (TIMPs)). Conclusions: Gene expression profiling identified specific dysregulated molecular pathways and SPINK1/TATI as the most overexpressed gene in HCV-positive HCC. These data highlight the importance of SPINK1/TATI as a tumor marker for HCV-induced HCC and may lead to a better understanding of HCV-induced hepatocarcinogenesis.