[Methodology and clinical implication of the identification of clonality in malignant lymphoma]

A variety of methods is now available to identify clonality of lymphoid neoplasia by recent progress in immunology and molecular biology. The target molecules for these include physiologically or pathologically altered genes/their products and virus-derived DNAs. Identification of clonality is important for more accurate diagnosis of lymphoma and, especially, related borderline lesions. It is also of considerable value in staging and follow-up study of the patients because higher sensitivity of polymerase-chain reaction made it possible to detect submicroscopic lesions including minimal residual disease after treatment. However, many lesions and phenomena which are clonal, but do not appear to be malignant, have been characterized. These may prompt an update of the conventional concept of "malignant lymphoma".