Differential WNT Gene Expression in Various Subtypes of Acute Lymphoblastic Leukemia

Dysregulation of WNT signaling has been reported in many malignancies. This study was conducted to investigate the expression pattern of 14 members of the WNT gene family in different immunophenotypic subtypes of ALL. Semiquantitative RT-PCR was performed on samples from 71 ALL patients and 36 age-matched healthy individuals. The ALL patients were categorized into B-ALL (76%), T-ALL (22.6%)and mixed lineage (1.4%) and the B-ALL cases were further classified into pro-B, pre-BI, pre-BII and immature/mature-B based on immunophenotypic results. Among the WNT genes, WNT-7B (p=0.026), WNT-9A (p=0.020) and WNT-16B (p=0.023) were significantly over-expressed, whereas WNT-2B (p=0.033), WNT-5A (p=0.016), WNT-7A (p<0.0001) and WNT-10A (p<0.0001) were down-regulated in B-ALL. Among the T-ALL subtype, however, significant down-regulation of WNT-2B, WNT-5B, WNT-7A, WNT-10A and WNT-11 was evident. Comparison between B-ALL subtypes showed significant overexpression of WNT-7B, WNT-9A and WNT-B in certain subtypes. Our results suggest contribution of the WNT genes in leukemogenesis of ALL.