[Probe of classification of adult acute lymphoblastic leukemia]

To investigate the biologic features of adult acute lymphoblastic leukemia (ALL), and reclassified our ALL patients according to the 2008 WHO classification.

Immunophenotype and cytogenetic/molecular genetic results were obtained by flow cytometry, R-banding and RT-PCR, respectively.

(1) A total of 412 newly diagnosed and previously untreated adult ALL patients, were 239 males and 173 females. Among 410 patients with available immunophenotypic results, 357 were B-ALL and 53 T-ALL. Myeloid antigen (MyAg) was higher expression in B-ALL than in T-ALL, and was correlated with the expression of CD34. (2) 93 Ph + ALL patients, mainly CD10 ALL, was associated with high WBC count and MyAg and CD34 expression. MLL rearrangement was found in 12 cases, mainly pro-B ALL. (3) 299 cases could be analysed, according to the 2008 WHO classification of ALL, including 126 B-ALL with recurrent genetic abnormalities, and 120 B-ALL not otherwise specified. Among the 126 B-ALL with recurrent genetic abnormalities, 92 were Ph + ALL, 10 MLL + ALL, 11 hyperdiploid, 9 hypodiploid, 3 E2A-PBX +, and 1 TEL-AML1 +. Patients with Ph +, MLL +, hypodiploid or E2A-PBX + were associated with older age, higher WBC count, higher HGB, higher peripheral blasts and higher LDH level as compared with other patients.

Combination of immunophenotype and cytogenetic-molecular profiles can provide a further detailed classification of B-ALL.