Absence of mutations in the Wilms' tumor gene WT1 in primary breast cancer

Background: It was recently demonstrated that the WT1 gene was overexpressed in primary breast cancer and that the high expression levels of WT1 mRNA significantly correlated with poor prognosis. However, it remained undetermined whether or not the WT1 gene expressed in breast cancer had mutations. Methods: Breast cancer tissues were obtained from 36 patients with breast cancer. WT1 genomic DNA was PCR-amplified and examined for mutations by direct sequencing. Results: The sequencing analysis showed the absence of mutations through the whole 10 exons of the WT1 gene in the 36 cases of primary breast cancer. Two different single nucleotide polymorphisms (SNP) without an amino acid change (Pro42, C to T in exon 1, and/or Arg300, A to G in exon 7) were detected in the WT1 gene in 31 (86%) of the 36 cases examined. Conclusion: The results indicate that the wild-type WT1 gene plays an important role in the tumorigenesis of primary breast cancer.