Molecular genetics and the diagnosis of lymphoma

Gene rearrangement analysis has emerged as a precise laboratory aid in the diagnosis and classification of malignant lymphoma and leukemia. Both clonality and lineage can be identified in lymphoid neoplasms by the demonstration of rearrangements of antigen receptor genes of the immunoglobulin supergene family--immunoglobulin and T-cell receptor genes. Rearrangement analysis is not only useful in differential diagnosis and classification, but also serves as a sensitive unique clonal marker to detect early occult recurrence in patients after therapy. In a similar manner, chromosomal translocations associated with specific disease types can be detected with DNA probes in Southern blot analysis without the use of conventional cytogenetics. Using this approach, one may diagnose specific chromosomal translocations associated with histologic types of lymphoma and leukemia. When appropriately applied, DNA rearrangement analysis complements conventional histology, immunophenotyping, and cytogenetics.