The expression of iASPP in acute leukemias.

Inhibitory member of the ASPP family (iASPP) is an evolutionarily conserved inhibitor of p53, and its expression is upregulated in human breast carcinomas expressing wild-type p53. To examine the role of iASPP in acute leukemia (AL), we analyzed iASPP mRNA expression in AL by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). PCR products were confirmed by restriction endonuclease BstX I digestion and sequencing analysis. The results showed that median levels of iASPP gene expression in cells of AL were significantly higher than those in cells from normal donors and AL patients in complete remission (CR) (P = 0.019, 0.021, respectively). There was no significant difference between acute lymphocytic leukemia (ALL) cells and acute myeloid leukemia (AML) cells (P = 0.593). The expression level of iASPP gene and its overexpression in M3 and M4EO were significantly lower than in other subtypes of AML. However, iASPP gene expression in AL cells was not associated with gender, age, initial white blood cell count or p53 type, but was associated with CD34 expression. The results of the present study suggest that iASPP gene overexpression may play an important role in the leukemogenesis and/or disease progression of AL.