Expression of Survivin and Its Splice Variants in Pediatric Acute Lymphoblastic Leukemia

Survivin is involved in the inhibition of apoptosis and the regulation of cell division. In addition to wild-type survivin (survivin-wt), at least four splice variants with differential functions (ΔEx3 and 3B antiapoptotic, and 2α and 2B proapoptotic) have been identified. Survivin is highly expressed in several cancers, including hematological malignancies. Although acute lymphoblastic leukemia (ALL) is the most frequent malignancy in children, studies that investigated survivin expression in ALL are limited, and there is no study on 3B and 2α expression in ALL. Therefore the expression of survivin-wt and its splice variants was investigated in pediatric B-cell ALL patients. The expression of survivin-wt and its four splice variants was investigated by quantitative real-time polymerase chain reaction in archival RNA samples of 35 pediatric B-cell ALL patients. Patients were divided into high- and standard-risk groups according to age, white blood cell count, extramedullary involvement, and genetic risk factors; expression of survivin variants was compared between these two risk groups. We found that the ratio of survivin-ΔEx3/wild type (WT) expression was higher in the low-risk group than in the high-risk group. Comparative analysis between the high- and low-risk B-cell ALL groups indicated that the survivin-ΔEx3/WT expression ratio could potentially be used in risk classification for pediatric B-cell ALL.