Functional studies to identify tumor suppressor genes

Techniques in somatic cell genetics have proven to be very important in the elucidation of genetic mechanisms in cancer and, in particular, the functional definition of tumor suppressor genes. Genetic complementation studies using microcell fusion have allowed the identification of specific chromosomes and particular chromosome regions that contain functional tumor suppressor genes for a variety of human cancers. In this article, the basic strategy for insertion of dominant selectable markers into human chromosomes is described, as are the methods for microcell fusion of tagged chromosomes into malignant cell lines. Molecular cytogenetic characterization protocols for microcell hybrids generated by such strategies are outlined. Finally, novel approaches to the isolation of dominantly tagged subchromosomal fragments for functional assays as well as to the isolation of new tumor suppressor genes are also described.