Serum leucine aminopeptidase in head and neck cancer

Serum leucine aminopeptidase (LAP) activity was assayed in patients with head and neck cancer. The levels were found to be significantly higher than the controls. However, the rise in serum LAP was nearly the same in all patients studied, irrespective of the character or histopathology of the lesion but varied with respect to the site involved, i.e. from about 40 per cent in cancer of the hypopharynx to more than 100 per cent in cancer of the nasopharynx. Serum LAP activity was found to increase with the extent of the lymph node spread. After treatment the levels were found to be reduced.