OBJECTIVETo explore the relationship between EGIL 1998 and WHO2008 criteria for the diagnosis of mixed phenotype acute leukemia (MPAL).

METHODSThe same group patients were diagnosed for MPAL by EGIL 1998 and WHO2008 criteria, respectively. The coincidence rate of diagnosis and therapeutic response of two diagnosis standards were compared.

RESULTSA cohort of 1835 de novo acute leukemia (AL) patients admitted to our hospital from February 1996 to October 2010 were retrospectively analyzed by applying both EGIL1998 and WHO2008 classification criteria. Seventy four patients were diagnosed with MPAL according to EGIL 1998, accounting for 4.0% of all AL cases. The main subtype is M/B (54 cases, 73.0%). While 81 patients were diagnosed as MPAL, accounting for 4.4% based on WHO 2008 criteria. The most common type is also M/B (63 cases, 77.8%). Fifty nine (79.7%) cases met both criteria. In the subtypes of M/B, M/T, M/B/T and B/T, the coincidence rate is 85.2% (46/54), 56.3% (9/16), 0(0/2) and 50.0% (1/2), respectively. In the 1761 cases excluded as MPAL by EGIL1998, 22 cases can be diagnosed as MPAL by WHO 2008 classification. (2) Among the patients diagnosed as B/M MPAL by WHO2008, 13 were MPAL with t (9; 22) (q34; q11.2)/BCR-ABL1, 1 was MPAL with t (v; 11q23)/MLL-rearranged, 49 was B/myeloid not otherwise specified (NOS), 14 was T/myeloid NOS and 4 was MPAL NOS-rare types. (3) The overall final complete remission rate of the patients diagnosed by EGIL1998, 2008 WHO, met both criteria, EGIL1998 but excluded by 2008 WHO and by 2008 WHO but excluded by EGIL1998 was 69.0%, 73.5%, 73.5%, 44.4% and 73.7%, respectively, with no significant difference between any two groups based on χ(2) test (P > 0.05).

CONCLUSIONSEGIL 1998 and WHO2008 criteria have reciprocity in the diagnosis of MPAL.