A loss of profilin-1 in late-stage oral squamous cell carcinoma.

BACKGROUND: The genes for PFN1 and TMSB4 are both highly expressed in oral tissue and both encode actin monomer binding proteins thought to play a role in cell motility and possibly other crucial parts of tumor progression. METHODS: Oral brush cytology of epithelium from oral squamous cell carcinoma (OSCC) was used to measure PFN1 and TMSB4 mRNA in OSCC, while immunohistochemical analysis of tissue was used to check protein levels. RESULTS: High but variable expression of mRNAs encoding these two proteins was observed suggesting they may contribute to tumor characteristics in a subset of OSCCs. Both proteins were highly expressed in normal appearing basal epithelium, in the cytoplasm, and perinuclear area, while expression was minimal in upper epithelial layers. In OSCCs, expression of these proteins varied. In tumors classified as later stage, based on size and/or lymph node involvement, PFN1 levels were lower in tumor epithelium. A control gene, KRT13, showed expression in normal differentiated basal and suprabasal oral mucosa epithelial cells and as reported was lost in OSCC cells. CONCLUSION: Loss of PFN1 in tumor cells has been associated with lymph node invasion and metastasis in other tumor types, strengthening the argument that the protein has the potential to be a tumor suppressor in late-stage OSCC.