WT1 mutations and polymorphisms in Southeast Asian acute myeloid leukemia.

Genomic alterations of the Wilms' Tumor 1 (WT1) gene have been reported to occur in patients with acute myeloid leukemia (AML). No data presently exists regarding the frequency of WT1 mutations in the Southeast Asian AML population. This study focused on WT1 exons 7-10 mutations and their correlation with other molecular markers and patients' characteristics. The zinc finger domain of WT1 gene covering exons 7-10 was directly sequenced. Six types of mutations were identified among 49 cases (12.24%); 4 localized on exon 7 and 2 on exon 9. Two novel mutations were identified including the insertion within codon 313 and codon 314. Patients harboring WT1 mutations seemed to have a younger age (29.5 vs 45.4 years), a higher white blood cell count (120.3 vs 19.8×10(9)/L), and a lower platelet count (54.2 vs 104.3×10(9)/L) as compared to those without the mutations although statistical differences could not be demonstrated. All exon 7 mutations were frameshift mutations and had NRAS mutation while exon 9 mutations were base substitutions and had FLT3-ITD mutation. Interestingly, the major allele for rs16754 single nucleotide polymorphism was G (25-homozygous and 6-heterozygous) which was in contrast to A in the Western reports. The frequency of WT1 mutation in the Southeast Asian AML was thus comparable to the figures reported from the West although the designated major allele for rs16754 polymorphism was different.