Gene Expression Profiling of Fixed Tissues of Lymph Node Metastasis in Hepatocellular Carcinoma

RNA was extracted from formalin-fixed specimens of paired intratumoral and peritumoral tissues of patients with lymph node-positive (n=20) or negative (n=20) HCC. A cDNA-mediated annealing, selection, extension, and ligation assay was performed with an array of 502 known cancer-related genes to identify differentially expressed genes in 80 RNA samples. Total RNA was purified from the tissue specimens using the High Pure RNA Paraffin Kit according to the manufacturer’s protocol. DASL experiments were performed to identify genes that were differentially expressed between the lymph node metastasis (LNM) and non-lymph node metastasis (NLNM) groups of matched intratumoral and peritumoral tissues by using A cDNA-mediated annealing, selection, extension, and ligation assay.