Immunohistochemical and histochemical markers of primary lung cancer, lung metastases, and pleural mesotheliomas.

Sections of primary lung carcinomas, lung metastases, mesotheliomas, and lung metastases of some rare mesenchymal tumors were incubated with different cytokeratin (CK), vimentin, desmin, and tissue polypeptide antigen (TPA) antibodies and with antibodies reactive with different hormones (ACTH, PTH, alpha-HCG, Calcitonin CT), CEA, carcinoma-associated antigen (CA1), secretory component (SC), neuron-specific enolase (NSE), alpha-1-antitrypsin (alpha-1-AT), lysozyme (lyso), and S-100 protein (S 100). CK antibodies derived from a 49 kD (reactive with simple epithelia [SE]) and a 67 kD CK polypeptide fraction (reaction with complex epithelia [CE] were useful differentiation markers for the four major groups of lung carcinomas. In one half of small cell carcinomas a positive reaction with NSE antibodies was found. S 100 and SC were good markers for papillary and bronchioloalveolar adenocarcinomas, whereas CEA was less important because of its reactivity with different types of lung carcinomas. To discern clear cell carcinomas of lung and renal origin a positive reaction with vimentin antibodies (some renal but not lung types) and with CA1 (no renal but all lung types) seemed to be useful. All hormone antibodies were of no importance as markers for difficult differential diagnosis, because positive reactivities were found in cases from every major carcinoma group. In addition, a Ca2+-activated adenosine triphosphatase (ATPase) was found in mesotheliomas but not in papillary adenocarcinomas.