Activation of PKC-dependent signaling with a phorbol ester-type DAG analog in the Kasumi-2 B ALL cell line, blocked at the precursor B stage, led to the induction of differentiation of the cells as detected by the loss or decrease of expression of CD10, TdT and RAG-1 and the induction of expression of the CD19, CD20, CD22 and FMC7 markers, as well as morphological changes. This evidence concerns the gene CD22 and acute lymphoblastic leukemia.