PARALLEL HYBRIDIZATION ANALYSIS OF MULTIPLE PROTEIN-KINASE GENES - IDENTIFICATION OF GENE-EXPRESSION PATTERNS CHARACTERISTIC OF HUMAN HEPATOCELLULAR-CARCINOMA

Hepatocellular carcinoma (HCC) is one of the major causes of human can cer deaths worldwide. To identify alterations of the genetic program a ssociated with human HCC, we designed a new protocol based on the high -density replica method to analyze protein kinase gene expression in n ormal liver, HCC, and HCC-derived cell lines. RNA was prepared for rev erse transcription and cDNA was used for PCR amplification of the cons erved catalytic domain of protein kinase genes. Initially, from a pair of HCC and the adjacent noncancerous tissues, we sequenced 228 sample s and identified 26 genes that represent different tyrosine kinase sub families. High-density grid filters were then prepared to assist the i dentification, by hybridization, of genes that are differentially expr essed in normal vs HCC samples. Eleven tyrosine kinase genes were test ed, and positive signals were reliably scored by doubly offset duplica tes and by two independent gene-specific probes. Of the 11 genes teste d, PDGF receptor-beta, MEKK-3, axl, and FGFR-4 are preferentially expr essed in tumor samples. Additionally, we analyzed protein kinase gene expression in five HCC cell lines and identified distinct kinase gene expression patterns in different cell lines. Our results suggest that multiple kinases are activated in different tumors and confirm that th ere is molecular heterogeneity in the mechanisms sustaining autonomous cell growth in liver tumor formation. (C) 1998 Academic Press.