Identification of molecular targets in head and neck squamous cell carcinomas based on genome-wide gene expression profiling.

DNA amplifications activate oncogenes and are hallmarks of nearly all advanced cancers including head and neck squamous cell carcinoma (HNSCC). Some oncogenes show both DNA copy number gain and mRNA overexpression. Chromosomal comparative genomic hybridization and oligonucleotide microarrays were used to examine 8 HNSCC cell lines and a plot of gene expression levels relative to their position on the chromosome was produced. Three highly up-regulated genes, NT5C3, ANLN and INHBA, were identified on chromosome 7p14. These genes were subjected to quantitative real-time RT-PCR on cDNA and genomic DNA derived from 8 HNSCC cell lines. ANLN and INHBA showed a strong positive correlation between mRNA expression and genomic DNA levels and a similar relationship was shown for the known oncogene, EGFR, at 7p11.2. In clinical samples, ANLN and INHBA showed a significantly higher expression in tumors than in normal tissues. Patients with high expression levels of INHBA had a shorter disease-free survival rate. Therefore, INHBA may be a promising prognostic marker of HNSCC.