The polymerase chain reaction: a new tool for the detection of minimal residual disease in haematological malignancies.

The polymerase chain reaction (PCR) is a novel technique for the in vitro amplification of specific short DNA fragments, which permits a selective and up to 10(7) fold enrichment of the target sequence. The method is increasingly being used for the molecular genetic analysis of hereditary, infectious and neoplastic disorders. The use of PCR for the detection of minimal residual disease in particular types of leukaemia or lymphoma, such as chronic myelogenous leukaemia expressing specific BCR/ABL-RNA and follicular non-Hodgkin lymphoma with the chromosomal translocation t(14;18) are reviewed. In acute lymphoblastic leukaemia clone-specific sequences from rearranged antigen receptor genes may be molecular markers suitable for amplification. Although PCR holds great promise for "molecular" staging and follow-up, several technical problems have to be kept in mind, and the clinical relevance of PCR-based evidence of minimal residual disease in haematological malignancies requires further investigation.