On the Heterochromatin Condensation State Diversity in Myeloblasts of Chronic Myelocytic and Acute Myeloblastic Leukemias - Abstract
The heterochromatin condensation state (HChCS) in myeloblasts was studied using the computer assisted optical densitometry in May-Gr?nwald – Giemsa-Romanowsky (MGGR). Stained bone marrow smears of patients who suffered from acute myeloblastic and chronic myelocytic leukemias. The results of the measurements demonstrated significant differences of the HChCS in peripheral nuclear regions between myeloblasts of acute myeloblastic (FAB classification M2) and the chronic phase of chronic myelocytic leukemias. In contrary to the chronic phase of chronic myeloid leukemia (CML), the HChCS in M2 acute myeloblastic leukemia (M2 AML) was significantly larger in the nuclear periphery. It should be added that the HChCS in the periphery of these M2 AML myeloblasts with the altered differentiation was similar to that in fully differentiated stages of CML granulocytes. The HChCS in myeloblasts with the differentiation ability in cultures originated from human leukemias was similar to that in bone arrow myeloblasts of CML, Thus, the large HChCS in the nuclear periphery of M2 AML myeloblasts apparently reflects an additional type of their known altered differentiation, On the other hand, it should be mentioned that some of M2 AML myeloblasts with a looser HChCS in the nuclear periphery were similar to those in CML or in growing Kasumi 1 and K 562 cell cultures with the cell differentiation ability. Such similarity suggests that a small population of such myeloblasts in M2 AML might possess the ability for
further differentiation. However, it remains unknown whether such cells in patients suffering from M2 AML might represent the origin of differentiated mature leukemic or not-leukemic granulocytes. In addition, the methodical approach used in the present study did not facilitate to distinguish exactly the facultative or constitutive heterochromatin in both M2 AML and CML myeloblasts.