Protein 1 (Clara cell protein) serum levels in lung cancer patients receiving chemotherapy.

As many antineoplastic drugs can cause injury to alveolar pneumocytes, Clara cells (nonciliated, nonmucous epithelial cells of the bronchioles) may also be damaged by such drugs. Protein 1 (P1) is an alpha-microprotein secreted by Clara cells. The effect of antineoplastic drugs on Clara cells is examined by the measurement of serum levels of P1 in patients with lung cancer receiving chemotherapy. Serum levels of P1 were studied in 36 patients with lung cancer, before chemotherapy and 5-7, 10-12 and 14-18 days after chemotherapy. One hundred and eight healthy subjects, matched by sex and age, acted as controls. There was no significant difference in P1 serum levels between patients with lung cancer and healthy controls. P1 serum levels decreased significantly 5-7 and 10-12 days after chemotherapy, recovering thereafter. We conclude that P1 serum levels do not differ between lung cancer patients and healthy controls, and that antineoplastic drugs inhibit the synthesis or secretion of P1 by Clara cells in the early period after the administration of medication.