Biological markers in lung cancer: an immunocytochemical approach.

In oat cell (small cell) carcinoma and, to some extent, in other histological types of lung cancer, improved forms of treatment have resulted in prolongation of survival and even cure. Progress is hampered by the lack of reliable biochemical markers such as those which have completely changed the management and outlook in testicular and gestational carcinoma. Carcinoembryonic antigen (CEA) has been of some value. Raised circulating levels of calcitonin and of adrenocorticotropic hormone (ACTH) are found in many patients with lung cancer but have not proved as useful for monitoring disease progression. It is probable that since lung tumors form a heterogeneous population, production of markers varies with histological type. Our approach has been to affinity purify those polyclonal antisera to potential lung tumor markers which are not yet available as monoclonal hybridoma antibodies and to examine 10 representative resection specimens of each of the four common carcinoma types--squamous, adeno-, large cell, and small cell using an indirect immunoperoxidase localization technique on formalin-fixed paraffin-embedded sections. Substances localized included CEA, epithelial membrane antigen, calcitonin, alpha and beta subunits of human chorionic gonadotropin, and human placental lactogen.