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What causes Wilms' tumor?
Last reviewed: 06.07.2025
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Wilms' tumor (nephroblastoma) is a malignant embryonic neoplasm of the kidney. Nephroblastoma accounts for about 6% of all malignant neoplasms in children, it is the most common kidney tumor, the second most common extracranial solid tumor of childhood and the second most common malignant tumor of the retroperitoneal space. Bilateral lesions are observed in 5-6% of cases. The incidence of nephroblastoma is 9 cases per 1,000,000 children. Girls and boys are affected with equal frequency. The peak incidence is at the age of 3-4 years. In 70% of cases, Wilms' tumor occurs in children aged 1-6 years, in 2% - in newborns (usually in a benign form). Sporadic cases of nephroblastoma are usually observed, but a familial predisposition is revealed in 1% of patients.
Causes and pathogenesis of Wilms tumor
The connection with developmental defects became the key to revealing the genetic nature of Wilms' tumor. Recessive tumor genes (suppressor genes) play an important role in the pathogenesis of nephroblastoma. Cytogenetic studies and molecular analysis methods made it possible to determine the polymorphism, homozygosity or heterozygosity of genes. Loss of heterozygosity leads to activation of the tumor suppressor gene and triggers the development of the malignant process.
A deletion in the short arm of chromosome 11 (11p13) was identified in Wilms tumor cells. The WT1 gene of Wilms tumor encodes a transcription factor that determines the normal development of renal tissue and gonads. Pathological linear mutation involving the MP gene was identified in patients with WAGR syndrome and Denys-Drash syndrome, as well as in patients with bilateral nephroblastoma. A specific mutation of the WTI gene is found in 10% of patients with sporadic Wilms tumor.
The second Wilms tumor gene (WT2) is located at locus 11p15.5, this gene causes the loss of specific heterozygosity by cells, which leads to tumor progression. The same chromosomal abnormality is determined in patients with Beckwith-Wiedemann syndrome and hemihypertrophy. The WT2 gene is inherited through the female line, it is formed as a result of genomic imprinting.
In 20% of patients with Wilms tumor, allelic loss of the long arm of chromosome 16 is detected. The existence of a gene for familial nephroblastoma is assumed, but its localization has not yet been established.