[Human leukemic blood leukocyte DNA contains more breaks than normal leukocyte DNA]

The filtration-fluorescence technique was used to estimate the number of DNA breaks in leukocytes of patients with chronic lympholeukemia (CLL) and chronic myelo-leukemia (CML). Leukocytes from CLL patients showed 1.5-3-fold higher level of DNA breaks in comparison to normal lymphocytes, the number of breaks correlated with the disease progress. The patients with CML also displayed the increased DNA break level. It was 4.4 times as high as that in normal lymphocytes and 1.5 as high as compared to normal granulocytes. In malignant course of the disease (2 cases), the level of DNA breaks in leukocytes was determined as 8-30 times higher than normal.