RESUMO
BACKGROUNDS: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.