Characterization of gene methylation in human papillomavirus associated-head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) has become one of the most common forms of cancer worldwide. Hypermethylation-induced silencing of tumor-associated gene has been proposed as an important cofactor in cancer pathology. This paper aimed to characterize the gene methylation patterns in human papillomavirus (HPV) associated-HNSCC. TIMP3 and APC methylation status in neoplastic (N = 92) and non-neoplastic tissues (N = 92) of HNSCC as well as their association with HPV infection were investigated via methylation-specific PCR assays. Results indicated that methylation level of TIMP3 was markedly higher in HPV-positive tumors as compared with HPV-negative tumors. Both TIMP3 and APC methylation were associated with lymph node metastasis and higher clinical stage of tumors. Patients with methylation at TIMP3 or APC had worse prognoses as compared to those without these alterations. This is the first study that shows a possible linkage between HPV infection and APC methylation. Methylation patterns of tumor-related genes may contribute to different disease prognosis in HNSCC according to the HPV infection status.