The bone marrow picture was left-shifted, and the marrow picture showed a large number of basophils and 5% primitive cells. There is also an increase in the number of basophilic middle-aged and late-stage granulocytes with leftward nuclear shift and coarse basophilic granules in the cytoplasm. What are the causes of the leftward shift of the bone marrow image in patients? The following is a brief introduction: the phenomenon of left shift of bone marrow image is a manifestation of basophilic leukemia, the pathogenesis of basophilic leukemia: the cause is unknown, most patients with basophilic leukemia come from the chronic phase of chronic granulocytic leukemia (CML), but acute basophilic leukemia can also appear, however, does not contain the Philadelphia chromosome. Certain patients with acute granulocytic and monocytic leukemia with t(6;9)(p23;q34) abnormalities have increased basophils in the bone marrow but not in the peripheral blood, whereas patients with CML have t(9;22)(q34;q11) abnormalities, both diseases have chromosome 9 (q34) abnormalities and both have increased basophils, suggesting that the chromosome 9 breakpoint gene may affect basophil production.