OPTION 1

֍ Oral and periodontal manifestations of leukemia may include leukemic infiltration, bleeding, oral ulcerations, and infections. The expression of these signs is more common with acute and subacute forms of leukemia than with chronic forms. Leukemic cells can infiltrate the gingiva and, less frequently, the alveolar bone. Gingival infiltration often results in leukemic gingival enlargement leukemia. Highest incidence is seen in patients with acute monocytic leukemia (66.7%), followed by those with acute myelocytic—monocytic leukemia (18.7%) and acute myelocytic leukemia (3.7%). It should be noted, however, that monocytic leukemia is an extremely rare form of the disease. Leukemic gingival enlargement is not found in edentulous patients or in patients with chronic leukemia, suggesting that it represents the accumulation of immature leukemic blast cells in the gingiva adjacent to tooth surfaces with bacterial plaque. 
The French-American-British (FAB) classification is an older system for describing AML, but it is still commonly used and is listed below for reference.
֍ M4: Myelomonocytic 
֍ MO: Myeloblastic without differentiation 
֍ M4eo: Myelomonocytic with eosinophils 
֍ Ml: Myeloblastic with little or no maturation 
֍ M5a: Monocytic without differentiation (monoblastic) 
֍ M2: Myeloblastic with maturation 
֍ M5b: Monocytic with differentiation 
֍ M3: Promyelocytic 
֍ M6: Erythroleukemic 
֍ M7: Megakaryocytic 
Reference: Carranza Periodontology 13th ed page no 214