Prognostic significance of Flotillin1 expression in clinically N0 tongue squamous cell cancer.

The present study aimed to investigate the clinical and prognostic significance of Flotillin1 (FLOT1) in clinically N0 tongue squamous cell cancer (cN0 TSCC). Real-time PCR and Western blotting analyses were carried out to examine FLOT1 expression in four tongue squamous cell cancer cell lines, primary cultured normal tongue epithelial cells, and eight matched pairs of oral tongue cancer samples and adjacent non-cancerous tissue samples from the same patient. Immunohistochemistry was performed to examine FLOT1 protein expression in paraffin-embedded tissues from 181 cN0 TSCC patients. Statistical analyses evaluated the diagnostic value and the associations of FLOT1 expression with clinical parameters. FLOT1 mRNA and protein levels were upregulated in tongue squamous cell cancer cell lines and cancerous tissues compared with that in TEC and adjacent non-cancerous tissue samples. The level of FLOT1 protein was positively correlated with clinical stage (P = 0.001), T classification (P = 0.009), N classification (P = 0.001) and recurrence (P = 0.018). Patients with higher FLOT1 expression had shorter overall survival times. Our results suggest that overexpression of FLOT1 can be found in patients with higher pathological stage, T classification, N classification or recurrence. FLOT1 expression is associated with cN0 TSCC progression and may be valuable for the prognostic evaluation of cN0 TSCC.