Glucose uptake in malignant tumors of the head and neck

Positron emission tomography (PET) studies have shown an elevated glucose uptake in squamous cell carcinomas of the head and neck (HNSCC). On a cellular level glucose uptake is mediated by specific glucose transport proteins. We have used immunohistochemistry to study the expression of different facilitative glucose transport proteins (GLUT) in the normal mucosa and in HNSCC. A weak expression of GLUT 1 was observed in epithelial cells of the normal mucosa. However, the expression of GLUT 1 was strongly elevated in epithelial cells of HNSCC. GLUT2, 3 and 4 were not detected in any of the epithelial tissues examined. An increased expression of GLUT 3 was found in inflammatory cells. The storage of glycogen showed a negative correlation to the GLUT 1 expression. While an increased glycogen storage was accompanied by a decreased GLUT 1 expression in highly differentiated epithelial cells, glycogen loss was associated with a strong GLUT 1 expression in less differentiated cells. The present study with PET indicates that the elevated glucose uptake of HNSCC is closely related to an increased expression of GLUT 1 in epithelial tumor cells.