OBJECTIVETo investigate the expression of beta-catenin in patients with leukemia and explore its significance in leukemias.

METHODSRT-PCR was used to detect the expression of beta-catenin in bone marrow mononuclear cells (BMMNCs) from patients with leukemia. Immunocytochemistry was in some of patients to detect the distribution of beta-catenin at the same time. The clinical significance of beta-catenin was analyzed in combination with patients' clinical information.

RESULTSExpression of beta-catenin was statistically higher in acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) samples than in normal donors (P = 0.001 and 0.016 respectively) and chronic phase chronic myeloid leukemia (CML) patients (P = 0.001 and P = 0.008 respectively), while there was no statistic difference between AML and ALL patients (P = 0.58). In addition, beta-catenin expression in chronic phase CML patients was like that in normal donors (P = 0.49), but increased significantly in blast crisis and accelerated phase. Immunocytochemical analysis revealed that BMMNCs from normal donors expressed beta-catenin on the plasma membrane and cytoplasma, while those from acute leukemia expressed beta-catenin to varying degrees in the nucleus as well. The expression of beta-catenin gene statistically showed the highest level in M5 (n = 15) and the lowest level in M3 (n = 18). No clinical features, such as, age, initial WBC count, therapy response rate, blast cell numbers or cytogenetic risk was found to be correlated with the expression of beta-catenin excepting for CD34+ positive rate (P = 0.004) in AML.

CONCLUSIONAs a key mediator of Wnt signal transduction way, overexpression of beta-catenin in leukemia cells indicates that it might be aberrantly activated in acute leukemia, accelerated or blastic phase of CML.