Wilms tumor, also known as nephroblastoma is a type of renal cancer that affects cells of the kidney. It is most common in children, and it accounts for about 5% of all childhood cancers. Children who are girls and African-American are more susceptible to this cancerous tumor. Like any other tumor, the Wilms tumor can vary in size and metastasize to other organs. There are several causes of nephroblastoma, but the most outstanding is occurrence by chance (sporadic). The sporadic occurrence of Wilms tumor is as a result of a genetic mutation that interferes with the growth of cells in the kidney. The average age of Wilms tumor diagnosis is three years, although it can develop as early as infancy or in later years, say at 15 years of age.
Is Wilms Tumor Painful?
Wilms tumor often grows quite large before any symptoms present themselves. The early sign of this cancerous tumor is swelling or a large lump on the stomach. Parents can easily notice the swelling while bathing or dressing their child. Despite the large size of Wilms tumor, it is not usually painful. Regardless, in some children, they may experience pain, including stomach pain.
Children with nephroblastoma will generally exhibit symptoms similar to other childhood ailments. Therefore, it is important that if your child shows any signs of sickness, you take him/her to the doctor, and proper diagnosis of the underlying problem done. Other symptoms of Wilms tumor include; constipation, fever, loss of appetite, nausea, blood in urine, fatigue, and high blood pressure which may result in chest pain, headaches, and shortness of breath.
Is Wilms Tumor Genetic?
Wilms tumor develops sporadically, and although there is a relationship between the tumor and particular birth defect syndromes, as well as a genetic mutation. Nevertheless, it is unclear why it occurs in healthy children with no birth defects and inherited genetic changes. Statistically, Wilms tumor caused by inherited gene changed accounts for only 1-2% of the cancer cases. Additionally, only a small percentage of Wilms tumor patients have a genetic syndrome. The common genetic syndromes associated with Wilms tumor include; WAGR (Wilms tumor, Aniridia, Genitourinary malformations, and Intellectual disability) syndrome, Beckwith-Wiedemann syndrome, and Denys-Drash syndrome. 
Researchers have made good progress on Wilms tumor through understanding how normal kidneys develop, and how that process can go wrong, thus resulting in nephroblastoma. Since the kidneys develop very early, as the fetus is growing, some of the cells that are to mature into the kidneys, may not develop well. In other words, the cells remain as early kidney cells, and they might remain so even after birth. By the age of 3 or 4 years, these kidney cells are supposed to have matured. In case that doesn’t happen, they might start growing uncontrollably, thus causing the development of Wilms tumor.
Genetically speaking, the main genes that are responsible for the control of cell development are oncogenes and tumor suppressor genes. The latter slows down cell division or causes cells to die, whereas the former supports cell growth, division, and keeping the cells alive. If there is a change in DNA resulting in failure of functionality of the oncogenes and tumor suppressor genes, an individual can get cancer. For Wilms tumor, the genetic mutations are thought to be of the WT1 and WT2 genes, which are tumor suppressor genes. Also, in a few cases, changes in the WTX and CTNNB1 genes can result in nephroblastoma.
Wilms tumor is most common in young children. However, even older children and adults can develop the tumor, but it is rare. Symptoms of cancer can manifest as those of other childhood diseases, so it is important that a diagnosis is done. Additionally, some children may not experience pain, despite already showing symptoms of the condition such as an enlarged growth, and swelling on the belly. Regardless, some kids usually experience abdominals pains. Wilms tumor has been associated with genetic disorders, but still, in cases where children have no such defects, it is unclear why they develop the tumor.