Abstract: A diagnostic technology to provide more efficient treatment for diagnosis of diseases such as leukemia, is provided according to the present invention. The present invention provides a method for identifying a stage of differentiation-maturation of a cell comprising the steps of: A) measuring an expression level of at least one cellular marker; and 10 B) determining the stage of differentiation-maturation of the cell based on the expression level. The present invention further provides a method for treating a subject based on a differentiation-maturation stage of a cell, comprising the steps of: A) measuring an expression level of at least one cellular marker; B) determining the differentiation-maturation stage of the cell based on the expression level; and C) providing to the subject an appropriate treatment based on the determined differentiation-maturation stage.