Serum phosphohexose isomerase levels in patients with head and neck cancer.

Serum phosphohexose isomerase (PHI) levels were estimated in 28 patients with head and neck cancer. The mean value was significantly higher when compared to the controls. There was no difference in mean PHI value with respect to the character of the lesion or with the histopathological type of growth. The activity was increased with the advancement of the stage of cancer. With radiotherapy, a gradual and significant decrease in serum PHI activity was observed.