<prompt> A 60 year old man presented with fatigue, weight loss and heaviness in left hypochondrium for 6 months. The hemogram showed Hb. 10gmdL,TLC 5 lakhsmm3, platelet count 4 lakhsmm3, DLC: neutrophil 55, lymphocytes 4, monocytes 2, basophils 6, metamyelocytes 10, myelocytes 18, promyelocytes 2 and blasts 3. The most likely cytogenetic abnormality in this case is -t 1 : 21t 9:22t 15:17Trisomy 21  <response>: In chronic phase of CML,there is excessive proliferation of myeloid cells of intermediate grademyelocytes metamyelocytes mature segmented neutrophils . Myeloblasts usually do not exceed 10 of cells in the peripheral blood bone marrow .An increase in propoion of basophils up to 10 is a characteristic feature of CML.In this case,heaviness on left hypochondrium is due to splenomegaly.In CML, the abnormality is due to reverse translocation between chromosome 9 22 forming Philadelphia chromosome .Reference :Harsh mohan textbook of pathology sixth edition pg no 357 