First of all, it is important to know that the normal red blood cells, white blood cells and platelets in the blood are derived from the proliferation and differentiation of “hematopoietic stem cells” in the bone marrow. There are many types of leukocytes, including granulocytes and monocytes (collectively called myeloid cells), as well as B lymphocytes, T lymphocytes, and NK cells. During the differentiation of normal leukocytes, if they are lymphocytes, they express markers of the lymphoid lineage and turn off expression of the myeloid lineage. Similarly, in the case of myeloid cells, myeloid markers are expressed and myeloid expression is turned off. However, in leukemia, the situation is different. Although lymphocytic leukemia expresses mainly lymphoid markers, due to abnormal differentiation, lymphocytes also express some myeloid markers, such as CD13, 33, 123, MPO, etc. Among these myeloid markers, only MPO expression is the most specific. In other words, without the expression of MPO, the other expressions will not affect the therapeutic effect of acute leukemia. Similarly, in myeloid leukemia cells, some lytic markers can be expressed, and many of them do not affect the therapeutic effect of myeloid leukemia, so parents should not worry too much.