Gene expression signature of HPV in head and neck squamous cell carcinoma

Introduction: Human Papilloma Virus (HPV) is associated with a subset of head and neck squamous cell carcinoma (HNSCC), between 15% and 35% of HNSCC harboring HPV, almost exclusively of subtype 16. Demographic and exposure differences between HPV-positive (+) and negative (-) HNSCCs suggest that HPV(+) tumors may constitute a subclass with different biology, while clinical differences have also been observed. In this study, gene expression profiles of HPV(+) and (-) tumors were compared to further explore the biological effect of HPV in HNSCC. Methods: Thirty-six HNSCC tumors were analyzed for gene expression using Affymetrix Human 133U Plus 2.0 GeneChip and for HPV using consensus primers for HPV L1, E6 and E7 by PCR and RT-PCR. Results: Eight (22%) of 36 tumors were positive for HPV, all of the HPV 16 subtype, and the HPV positive samples also expressed viral HPV E6 mRNA determined by RT-PCR. Patients with HPV(+) HNSCCs were on average younger than those with HPV(-) tumors (mean age 50.2 vs. 58.7). Statistical analysis using Significance Analysis of Microarrays (SAM) based on HPV status as a supervising parameter resulted in a list of 91 genes that were differentially expressed with statistical significance. Results for a sub-set of these genes were verified by RT-PCR. Genes highly expressed in HPV(+) samples included cell cycle regulators (p16INK4A, p18 and CDK2) and transcription factors (TAF7L, RFC4, RPA2 and TFDP2). The microarray data were also investigated using DIGMap to map genes by chromosomal location. A large number of genes on chromosome 3q24-qter was found to be overrepresented in HPV(+) tumors. Conclusion: The gene expression profile associated with HPV reflects alterations in cell cycle and proliferation signals. Further investigation of differentially expressed genes may reveal the unique pathways in HPV(+) tumors that may explain the different natural history and biological properties of these tumors. These properties may be exploited as a target of novel therapeutic agents in HNSCC treatment.

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Slebos RJ, Yi Y, Ely K, Carter J, Evjen A, Zhang X, Shyr Y, Murphy BM, Cmelak AJ, Burkey BB, Netterville JL, Levy S, Yarbrough WG, Chung CH