Human papillomavirus‐stratified analysis of the prognostic role of mi R ‐21 in oral cavity and oropharyngeal squamous cell carcinoma

Human papillomavirus ( HPV ) infection plays a significant role in the development and progression of head and neck squamous cell carcinoma ( HNSCC ). Expression of mi R ‐21 has a prognostic role in a wide variety of cancers. The upregulation of mi R ‐21 suppresses a number of target genes, including phosphatase tensin homologue ( PTEN ) and programmed cell death 4 ( PDCD4 ). We investigated the association between the expression of mi R ‐21 and the clinical features of HNSCC using stratified analysis based on HPV infection status. HPV status and mi R ‐21 expression in HNSCC tissues from 167 patients were evaluated using in situ hybridization. The expression of PDCD4 and PTEN was examined by immunohistochemistry. The up‐regulation of stromal mi R ‐21 expression occurred in 40.6% of HPV ‐negative samples and 28.3% of the HPV ‐positive group. In HPV ‐stratified multivariate analysis, high mi R ‐21 expression was associated with poor cancer‐specific survival in HPV ‐negative tumors, but not in HPV ‐positive tumors. There was a significant association between mi R ‐21 and cytoplasmic PDCD4 overexpression in HPV ‐negative HNSCC s. We suggest that stromal mi R ‐21 expression is an independent prognostic factor in HPV ‐negative tumors and mi R ‐21 may play different roles depending on HPV infection status.