DNA fingerprinting in the detection of residual disease in acute leukemia

DNA-fingerprint (DNA-F) analysis of leukemic cells can reveal new restriction fragments in some patients with acute leukemia. These genomic alterations can be used as molecular markers of residual disease. In this study, the sensitivity and clinical use of DNA-F analysis was evaluated. The detection limit for minority DNA was studied in six cell dilution series. An increasing ratio (1-20%) of cells was mixed with cells from another individual; intense extra bands could be identified in the DNA extracted from cell mixtures containing 5% of minority cells. In clinical samples from five of 19 ALL and six of 18 AML cases, the DNA-F of blast cells had new bands which could be followed during remission; in two cases the extra bands were intense enough to be detected at less than 5%. Studies of 37 patients with leukemia demonstrated that DNA-F analysis provides an additional tool for the detection of residual disease in acute leukemia.