miRNA expression in head and neck squamous cell carcinoma (HNSCC)

The involvement of microRNAs (miRNAs) in cancer and their potential as biomarkers of diagnosis, prognosis and response to therapy is becoming increasingly appreciated. The etiology of head and neck squamous cell carcinoma (HNSCC) is predominantly associated with the synergistic effects of tobacco and alcohol use, as well as Human Papilloma Virus (HPV) infection, which embodies a distinct clinical and biological phenotype. We sought to examine whether the profile of miRNAs in HNSCC varies based on HPV status, and to identify specific miRNAs altered in head and neck carcinogenesis. Total RNA was isolated from 16 HNSCC fresh frozen primary tumors, 5 fresh frozen non-diseased head and neck epithelial tissues, and 2 HNSCC cell lines. The miRNA profile of 662 individual miRNAs in these tissues was examined by microarray. 18 miRNAs are significantly altered in their expression between normal tissues and HNSCC tumors and 5 miRNAs are identified as significantly differentially expressed between HPV-positive (HPV+) and HPV-negative (HPV-) tumors. A striking difference in expression pattern of miRNA was also observed between primary tissues and cell lines. These data suggest that the pattern of miRNA expression may be reflective of disease etiology, and may be useful in the realm of diagnostic biomarkers defining broadly responsive prevention and treatment strategies for HNSCC. These data also suggest that cultured tumor cell lines may be inappropriate for novel miRNA biomarker identification. Keywords: miRNA; Disease-state analysis Expression of 662 individual miRNA was assessed in16 HNSCC fresh frozen primary tumors, 5 fresh frozen non-diseased head and neck epithelial tissues, and 2 HNSCC cell lines were arrayed