Immunohistochemical Studies on Small Cell Lung Cancer

Abstract

Seventy cases of pulmonary carcinoma, consisting of 20 cases of squamous cell carcinoma, 22 cases of adenocarcinoma and 28 cases of small cell carcinoma, were examined immunohisto-chemically using the peroxidase anti-peroxidase method, and antisera raised against carcinoembryonic antigen, keratin, neuron specific enolase, Leu-7, beta-2 microglobulin. The immunoreactivity of NSE, and of Leu-7 were very different among oat cells, intermediate cells, and combined subtypes of small cell lung cancer, while Leu-7 was rarely seen in adenocarcinoma or squamous cell carcinoma. Keratin was demonstrated not only in non-small cell lung cancer but also in intermediate and combined types of small cell lung cancer. These results seems to support the "Y" concept which describes the relationship between non-small cell lung cancer and small cell lung cancer. Besides the WHO classification of 1981, which divides the small cell lung cancer into oat cell, intermediate and combined subtype, the usefulness of a tentative classification of International Association for Study of Lung Cancer (IASLC) which divides them into classic (pure), variant, and combined type was discussed.