Fluorescence in situ hybridization (FISH) in the molecular cytogenetics of cancer

In this review, we discuss the developments of fluorescence in situ hybridization (FISH) and place them in the context of their applications in cancer research. These methods are not only very useful for the causal analysis of the development and spread of certain tumors, they are also efficient tools for tumor diagnosis. Although a review of all of the literature in this field is not possible here, many of the major contributions are summarized along with recent work from our laboratory. Our group contributes to the goal of functional identification of tumor growth antagonizing genes. FISH and molecular analyses have shown that the short arm of human chromosome 3 is frequently deleted in kidney, lung, breast, uterus, testis and ovary carcinomas. Deletion-mapping studies have outlined several separate deletion prone regions in different tumors, namely 3pter-p25, p22-p21.3, p21.1-p14 and p14-p12, which may contain putative tumor suppressor genes (TSGs). Candidate suppressor genes isolated from frequently deleted regions need to be assayed for possible tumor-antagonizing ability by functional tests. We have developed a functional test system, the microcell hybrid (MCH) based "elimination test" (Et). The Et is based on the introduction of a single human chromosome into tumor cells of human or murine origin, via microcell fusion. The MCHs were analyzed by FISH painting and PCR for the elimination or retention of specific human chromosome 3 (chr. 3) regions after one or several passages in severe combined immunedeficient (SCID) mice. We have defined a common eliminated region (CER) on chr. 3p21.3. CER is approximately 1 megabase (Mb) in size. We have covered this region with PACs (bacteriophage PI based artificial chromosome) and used FISH mapping for localization and ordering PACs and cosmids on the chromosome 3 and high-resolution free chromatin/DNA fiber FISH to orient the PAC contig, to measure the lengths of PACs, and to establish their order. Activation of cellular oncogene by chromosomal tanslocation, which brings an oncogene under the influence of a highly active chromosome region, appears to play a pivotal role in the genesis of certain hematopoetic and lymphoid tumors. We have detected specific chromosomal translocations by FISH painting in mouse plamacytoma (MPC), human Burkitt lymphoma (BL) other B-cell derived tumors. We have showed in a murine sarcoma derived line (SEWA) that FISH can be also be used for detection of amplified oncogene (c-myc) and the linked locus (pvt-1). We have also applied the FISH technique for visualization of integrated and episomal Epstein-Barr virus (EBV) genomes and EBV transcripts in EBV-carrying B-cell derived human cell lines.