PTEN and miR-26b: Promising prognostic biomarkers in initiation and progression of Oral Squamous Cell Carcinoma.

Abstract

Oral Squamous Cell Carcinoma (OSCC) is the most common malignancy of the oral cavity. Phosphatase and TENsin homolog (PTEN) is a well-known tumor suppressive gene regulated by several biomarkers including a small single-stranded molecule, microRNA26b (miR-26b). Here, we studied the expression of PTEN and miR-26b in OSCC specimens in comparison with adjacent normal mucosa. The expressions of PTEN and miR-26b genes were evaluated at mRNA level in OSCC and adjacent normal fresh frozen tissues in 49 patients using Quantitative Real-Time PCR and analyzed their associations with clinicopathological factors. The expression level of PTEN was significantly lower in OSCC specimens comparing with adjacent normal tissues (P-value=0.000). The expression of PTEN was associated with T stage (P-value=0.006) and N stage (P-value=0.043). A nonsignificant decrease in miR-26b expression level was also observed in OSCC tissues. Additionally, in patients with more aggressive tumoral behavior, including vascular invasion (P-value=0.012) and positive N stage (P-value=0.02), significant decreases were found. These findings suggest that inactivation of PTEN may have an impact on initiation and progression of OSCC. Additionally, miR-26b might have a tumor suppressive role in OSCC.