[The minimal residual disease (MRD) in hematological malignancies]

Molecular genetic and cytoimmunological markers have been applied for the detection of minimal residual disease (MRD) in hematological malignancies. These markers include surface markers or rearranged T-cell receptor and immunoglobulin genes in the lymphoid malignancies and fused genes associated with chromosomal translocations such as BCR-ABL in t(9;22) or PML-RAR alpha in t(15;17) in myeloid malignancies. The expression of the WT1 gene is recognized as the universal tumor marker for a wide variety of hematological malignancies. Using these sensitive markers, a tumor cell in 10,000 to 1,000,000 normal cells can be detected. By examining a large number of patients, it has been shown that the MRD in the early phase of chemotherapy has a correlation with the prognosis of childhood ALL. Based on these observations, a new strategy of chemotherapy in which the post-remission therapy is modified based on the MRD results has begun. The amount of tumor cells contaminated in the autologous stem cell grafts in ALL patients might be related to the prognosis. The diagnosis of MRD will be used as an important routine examination in chemotherapy for leukemia/lymphoma patients.