Classification of acute myeloid leukemias, according to the French-American-British group and the National Cancer Institute Laboratory, according to JAIN et al., 1991

TypeCharacteristic of blood and bone marrow constants
AUL– Non-reactive blast cells for usual markers and antibodies for myelocytes and lymphocytes; terminal deoxynucleotidyl-transferase and negative surface immunoglobulins;
M0– Positive peroxidase in <3% of blast cells. Blast cells indicate restricted myeloid differentiation by electron microscopy (peroxidase-positive granules) and/or by immunotyping.
M1– Blast cells >90% of non-erythroid cells, differentiated granulocytes and monocytes <10%; peroxidase-positive cells or Sudan black B >3%.
M2– Myeloblasts between 30–90% of non-erythroid cells; differentiated granulo-cytes >10%; monocytic cells <20% and positive non-specific esterase <20% of non-erythroid cells.
M3– Blast cells >30% of non-erythroid cells. Abnormal, predominantly hypergranular, hypogranular or microgranular promyelocytes, with reniform or bilobated nuclei. Bundle coupling usually appears.
M4– Myeloblasts and granulocytes >20%, monocytic cells >20% and positive non-specific esterase >20%. Blood monocytes >5/μl or low serum concentration or urinary lysosomal concentration 3-fold higher than normal. M4E0 has >5% eosinophils with abnormal granulations.
M5– Monocytic cells >80% of non-erythroid cells, many of which with intensely positive non-specific esterase; M5a has >80% monoblastic cells; M5b has <80% monoblasts with the predominance of differentiated monocytic cells.
M6– Medullary erythroid cells >50%. Myeloblasts and monoblasts >30% in the blood and bone marrow, but 30% of non-erythroid cells in the bone marrow.
M7– Megakaryoblasts >30% of all nucleated cells or non-erythroid cells in the bone marrow.
– The histological sections in the bone marrow frequently show myelosclerosis or reticulin and occasional growth of megakaryocytes. Abnormal megakaryoblasts are also present in the blood. Blasts are positive for IIb/IIIa glycoprotein granules, presenting foci of alpha-naphthyl acetate esterase, fluoride- positive sensitivity, and are negative for peroxidase, Sudan black B and alpha-naphthyl butyrate esterase.
MDS– Blast cells <30% of all nucleated cells and non-erythroid cells, usually normal, hyper- or just hypo-cellularization of the marrow; increase in the number of ring sideroblasts and uni-, bi- or trilinear dyshematopoiesis. Blood shows refractory anemia.
CMMoL– It is a form of myeloblastic syndrome, with blast cells <20% and absolute monocytosis of >l/μl in the blood.

From: Chapter 17, TUMORS OF HEMATOPOIETIC AND LYMPHOID TISSUES

Cover of Comparative Oncology
Comparative Oncology.
Baba AI, Câtoi C.
Copyright © 2007, The Publishing House of the Romanian Academy.

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