In Vitro Study of the Biology of Small Cell Carcinoma of the Lung

We have developed three types of experimental systems for the study of SCCL: (1) serially heterotransplanted tumors in athymic nude mice; (2) continuous, clonable cell cultures; and (3) direct clonogenic assays for tumor specimens. These systems have their own individual advantages, applications, and limitations, but these are interrelated and complementary. The study of these systems has greatly aided our understanding of the biology of SCCL, and its relationship to other lung cancers and the APUD cell system. In addition, new markers for SCCL have been identified, such as a creatine kinase and its BB isoenzyme (CK-BB). These cellular markers may have clinical applications, as serum levels of CK-BB are an indicator of tumor burden. Assays for clonogenic tumor cells may permit selection of optimal drug combinations for the treatment of individual tumors. Variant cultures having the morphology of SCCL, but lacking some or all of the other features, have been identified. While our systems have been used primarily for biological studies, they have clinical applications for both diagnostic and therapeutic purposes.