Expression of Glut-1 and Glut-3 in untreated oral squamous cell carcinoma compared with FDG accumulation in a PET study.

Increased expression of glucose transporter-1 (Glut-1) and glucose transporter-3 (Glut-3) has been reported in many human cancers. The mechanism of glucose entry into oral squamous cell carcinoma (OSCC) remains unclear. In this study we investigated, in untreated human OSCC, the relationship between tumour fluorine-18 fluoro-2-deoxy-d-glucose (FDG) accumulation and the expression of Glut-1 and Glut-3, as well as the association between the expression of Glut-1 and of Glut-3. All patients underwent FDG positron emission tomography (PET) pre-operatively. Standardised uptake values (SUVs) were used for evaluation of tumour FDG uptake. Final diagnoses were established by histology. Immunohistochemical staining results were evaluated according to the percentage (%) of positive area, intensity and staining score. Tumour sections were stained by immunohistochemistry for Glut-1 and Glut-3. Glut-1 immunostaining revealed that 18 (94.7%) of the 19 tumours stained positively, while Glut-3 immunostaining yielded positive findings for 16 (84.2%) tumours. Overall, a relatively low level of agreement (36.8%) in the staining score was observed between Glut-1 and Glut-3 expression. No relationship was found between the staining pattern and tumour differentiation or T grade classification in either Glut-1 or Glut-3 immunostaining. Furthermore, no relationship was found between increased FDG SUV and tumour differentiation, but the former did correlate with T grade. In conclusion, high FDG uptake values were seen in OSCC with overexpression of Glut-1 and Glut-3. However, no significant correlation was found between FDG SUV and Glut-1 or Glut-3 expression.