Differentially expressed transcripts in neoplastic hepatic nodules and neonatal rat liver studied by cDNA microarray analysis

The molecular mechanisms underlying hepatocarcinogenesis remain unclear. Wistar rats treated with 2-AAF develop hepatocarcinoma in histologically well-characterised stages. In our study, cDNA microarrays were used to measure the expression of 3,000 genes during the progression of liver carcinogenesis in persistent neoplastic nodules. Because tumours frequently revert into a more poorly differentiated phenotype, we also studied the expression of the same set of transcripts in neonatal rat liver. Approximately 2,000 transcripts gave a detectable signal in experiments comparing gene expression in nodules and control tissue. Approximately 8% of these were identified as differentially expressed in liver nodules. The differentially expressed genes fell into several categories with putative or demonstrated roles in signal transduction, metabolism, detoxification, cell-structure and transport. Many of the differentially expressed genes in nodules were not previously known to be regulated during liver carcinogenesis. A universal transcript profile for gene expression in hepatic liver nodules and neonatal liver has been created.