Molecular gene rearrangement analysis in hematopathology.

The advent of monoclonal antibody technology revolutionized the understanding of lymphoid and myeloid differentiation and greatly enhanced the ability to make a more accurate diagnosis. However, certain limitations became evident as monoclonal antibodies were increasingly applied to diagnostic hematologic problems. The T-cell antigens identified by monoclonal antibodies are not true clonal markers. B-cell immunoglobulin light chain restriction is a true clonal marker, but immunoglobulin is not expressed by many B-cell malignancies, diminishing its usefulness as a clonal marker. The development of molecular biologic techniques to augment diagnosis of hematologic neoplasms has revolutionized the understanding of neoplasia. Gene rearrangement analysis yields information concerning clonality and lineage. Gene rearrangement analysis can also identify chromosome breakpoints and translocations that correlate with specific diseases or prognoses. The purpose of this review is to familiarize the reader with the current applications of molecular biology to hematologic processes and to chart future directions of the application of these powerful techniques to diagnostic hematopathology.