[Prognostic effect of cytoplasmic CD79a expression in acute myeloid leukemia with t(8;21)]

Although cytoplasmic CD79a (cytCD79a) is a highly lineage-specific marker of B lymphoid cells and plays an important role in the diagnosis of acute leukemia, its clinical significance is not fully understood. We aimed to investigate the relationship between cytCD79a positivity and survival probability, and to evaluate the prognostic value of cytCD79a expression in AML with t(8;21) (q22;q22).

A total of 68 cases of AML with t(8;21)(q22;q22) were diagnosed based on conventional morphology, cytochemistry, flow cytometrty, and cytogenetic and molecular genetic analysis. Immunohistochemistry of cytCD79a was performed retrospectively. Laboratory and clinical findings were reviewed.

Five patients among 68 AML with t(8;21)(q22;q22) revealed cytCD79a positive reaction; scores for myeloid lineage/B-lymphoid lineage were 5/3-3.5. Among the five cytCD79a positive patients, only one patient was a child. Three patients were with refractory AML or relapsed, and two patients died within 10 months. Median survival time of cytCD79a positive group was shorter (8.0 months) than that (61.3 months) of cytCD79a negative group. The survival probability of the cytCD79a expression group was significantly lower than classical AML with t(8;21)(q22;q22) (P=0.0001).

These findings emphasize the necessity of investigating cytCD79a, especially in AML with t(8;21)(q22;q22), for a different clinical prognostic value.