The activity of neutrophil myeloperoxidase in patients with lung carcinoma.

MPO activity in the neutrophils has been evaluated in 25 patients with lung carcinoma. Surprisingly for us we observed no differences between patients and controls in the total MPO activity. However, we noted the increase in the percentage granulocytes with the first and fourth degree of scores in cancer patients in comparison to normal adults. The highest activity was characterized by the distribution of this enzyme not only in granules but also outside them. Any changes in the total activity of MPO may reflect the balance between the factors which may stimulate it as tumor promoters enhancing the production of superoxide anion or the inhibitory effect of plasma. Diffuse enzymatic reaction may be due to some functional abnormalities of phagocytosis or membrane damage by the MPO system. The role of MPO in anticancer mechanisms is briefly discussed.