ABSTRACT
Leukemia and lymphoma are hematologic malignancies that originate from hematopoietic stem cells. They are stratifi ed primarily according to the lineage of the neoplastic cells into myeloid, lymphoid, histiocytic or dendritic cell, and mast cell
neoplasms. Within each category, a combination of morphologic features, immunophenotype, genetics, and clinical syndromes defi ne further distinct diseases.1 The cell lineage is determined by identifying the antigenic determinants (epitopes) of the cells with specifi c antibodies, a process called immunophenotyping. Furthermore, the neoplastic cells have consistent and reproducible patterns of antigen expression. Thus, these patterns are used in disease identifi cation and are a valuable tool in diagnostic hematopathology. In some instances, the immunophenotype has prognostic signifi cance; however, other factors such as the presence or absence of specifi c genetic alterations appears to be more informative than immunophenotyping alone in predicting disease progression and response to therapy.2
