FISH and related techniques in the diagnosis of lymphoma

Many malignant lymphomas are characterized by recurrent genetic abnormalities. These include numerical abnormalities, deletions and reciprocal translocations. In this chapter, we have focused on the detection of chromosomal translocations in B cell lymphomas and discussed some trisomies in lymphomas and CLL. FISH is a well developed molecular method by which it is possible to detect numerical and structural chromosomal abnormalities. We addressed various aspects of metaphase, and especially interphase, FISH and also described the recently developed DNA fibre FISH technology. Using this method, it is possible simultaneously to detect and map chromosomal breakpoints. FISH is also compared with more conventional detection methods such as banding analysis, Southern blot analysis and PCR for the translocations t(8;14) and variant translocations in Burkitt's lymphoma, t(14;18) in follicular lymphoma and t(11;14) in MCL. Other breakpoints in B cell lymphoma are also discussed. It might be concluded that the rapid development in interphase and DNA fibre FISH will provide us with quick, easy and cheap tools to identify specific chromosomal translocations and other genomic abnormalities in human tumours.