Wilms Tumor Causes, Risk Factors, and Prevention
“Cancer” is a general word for a wide grouping of diseases in which the building blocks of the body—cells—grow and replicate abnormally. While some, although not all, types of cancers in adults are linked to lifestyle choices such as smoking or sun exposure, childhood cancers such as Wilms tumor are not linked to lifestyle choices. Moreover, it is important to note that childhood cancers cannot be prevented.
Wilms tumor is the most common form of kidney cancer in children. Scientists are just now beginning to understand the normal development of the kidneys in young children and how this development can potentially develop into Wilms tumors and other forms of kidney cancer in children. This research indicates that most cases of Wilms tumor seem to be linked to gene mutations that govern how the kidneys develop. While in a limited number of cases, these gene mutations may be inherited from a parent, in the vast majority of cases, the mutation is spontaneous and unpredictable.
Just what is a gene mutation? To understand this concept, it is important to understand the basic building blocks of our body. Every cell in the human body is governed by chromosomes built from long strands of DNA. The DNA, grouped into units called genes, instructs the cell’s growth, development, and replication. Oncogenes govern when cells grow, divide, and stay alive. Tumor suppressor genes slow down cell division or cause cells to die at the appropriate time. A gene mutation is a random change in the DNA sequence contained within the cell, potentially altering the instructions the gene receives. In some cases, the gene mutation may turn on oncogenes or turn off tumor suppressor genes.
Wilms tumors may be caused by gene mutations in the kidneys as they develop in the fetus or very young child. Instead of developing into mature kidney cells, some cells may stay as early kidney cells, remaining in clusters in the kidneys of babies after birth. In most cases, these early kidney cells slowly develop into mature kidney cells over the course of several years. In a limited number of cases, however, scientists believe that certain gene mutations may cause these clusters of undeveloped kidney cells to develop into Wilms tumors. Researchers have linked a small number of Wilms tumor cases to mutations (or absence of) the WT1 or WT2 genes, tumor suppressor genes usually located on chromosome 11. Other cases have been linked to gene mutations to the WTX gene, located on the X chromosome, as well as in the gene known as CTNNB1. Again, the specific cause of these gene mutations is unknown.
Are there Risk Factors for Wilms Tumor?
Wilms tumor has been linked to a certain number of risk factors usually involving genetic syndromes and/or birth defects relating to gene mutations. The most common syndromes that correlate closely with Wilms tumor include:
- WAGR syndrome: Children with this syndrome are missing part of chromosome 11, and have a 30-50% chance of developing Wilms tumor. For children with WAGR syndrome, Wilms tumor usually develops at an earlier age, and is more likely to form in both kidneys.
- Denys-Drash syndrome: Linked to mutations in the WT1 gene, this syndrome causes the kidneys to cease functioning at a very young age. The risk for Wilms tumor is very high for children with this syndrome.
- Frasier syndrome: As with Denys-Drash syndrome, Frasier syndrome is linked to mutations in the WT1 However, kidney function is impacted much later in life. Although the risk of Wilms tumor is high, the risk of reproductive cancers is higher.
- Beckwith-Wiedemann syndrome: Caused by a defect in chromosome 11 impacting the WT2 gene, children with this syndrome tend to have enlarged organs and tongue and may have an enlarged limb on one side of the body.
Is family history a risk factor? About 1-2% of children with Wilms tumor have a relative, usually not a parent, with Wilms tumor. Scientists believes that these children have inherited an abnormal gene, putting them at greater risk of developing Wilms tumor. Again, however, it is important to stress that in the vast majority of cases, the gene mutations thought to have caused Wilms tumor are spontaneous, not inherited.
About American Childhood Cancer Organization
American Childhood Cancer Organization (ACCO) is a non-profit charity dedicated to helping kids with cancer and their families navigate the difficult journey from cancer diagnosis through survivorship. Internationally, ACCO is the sole U.S. member of Childhood Cancer International (CCI), the largest patient-support organization for childhood cancer in the world. Here in the United States, ACCO promotes the critical importance of ensuring continued funding into new and better treatment protocols for childhood cancer. And most importantly, ACCO is focused on the children: developing and providing educational tools for children fighting cancer and their families, empowering them in their understanding of childhood cancer and the medical decisions they must make during this difficult journey. All of ACCO’s resources are available free of charge for families coping with childhood cancer.