Integrative analysis of gene alterations and immunoexpression profiles of cell cycle checkpoints in oral squamous cell carcinoma

BACKGROUND: Oral squamous cell carcinoma (OSCC) represents 95% of all cancers of the head and neck region. The five-year survival rate of OSCC patients is about 60% and has not gone throw significant improvements despite recent advances in molecular biology, or the identification of key pathways in its pathophysiology such as cell cycle. OBJECTIVE: 1) to analyse the inmunoexpression of cell cycle checkpoints (CPs) in an OSCC institutional cohort and to relate it to clinicopathological features and survival, and 2) to study CPs-related genes in the OSCC subset of the TCGA database. METHODS: Immunohistochemistry (IHC) for p16 INK4a , p21 CIP1 , cyclin D1 and p27 KIP1 protein expression was quantified by tissue microarray analysis in 68 samples from OSCC patients. In order to analyse its correlation with genetic information, a cohort belonging to The Cancer Genome Atlas (TCGA) database was analysed. RESULTS: Of 68 patients, 34 (50%) developed recurrence, and 36 (52.09%) died as a result of disease progression (mean survival 34.09 months). IHC staining for nuclear cyclin D1 was associated with worse staging and tobacco use. p16 INK4a , p21 CIP1 , cyclin D1, and p27 KIP1 expression was unrelated to overall survival. No statistically significant correlation linked the CPs-related genes mutations to OSCC overall survival in the TCGA database. CONCLUSIONS: CPs variations at a phenotype and genotype level seem not to affect significantly clinicopathological features and survival in the studied OSCC cohorts.