Wilms' Tumor Causes and Risk Factors

Conditions & Diseases: Cancers

Kidney Cancer - Wilms' Tumor

Causes and Risk Factors

The exact causes why certain children develop Wilms’ tumor are not known yet, but medical researchers have made progress in understanding some of the mechanisms that lead to Wilms' tumor.

The Wilms’ tumor form when undifferentiated kidney cells do not correctly mature and remain as fetal kidney cells. These cells can collect in clusters, grow and divide abnormally causing tumors to form. In some cases, the impaired maturation process of the kidney cells, that lead to Wilms’ tumors, is caused by a mutation that occurs in two genes called WT1 and WT2. These mutations cause an overgrowth in certain tissues.

However, these mutations can either be inherited, or are acquired early in the children's life or even before birth. In other cases (11 to 17 percent), the Wilms’ tumors display an abnormality in the chromosome 1 or chromosome 16. Unfortunately, these tumors are more likely to spread or to relapse after treatment.

Some of the risk factors that are associated with Wilms' tumor include:

Age: Children between the age of 3 and 5 are at higher risk to develop Wilms' tumor.

Gender: The risk of developing Wilms' tumor is slightly higher in girls than in boys.

Sex: For the US population, the risk for developing Wilms' tumor is slightly higher among African Americans that Caucasians, and is lower among Asian Americans.

A family history of Wilms' tumor: Between 1 to 3 percent of the children that suffer from Wilm’s tumor have one or more relatives with this type of kidney cancer. In these cases, researchers believe that the children inherited a mutated gene from one of the parents, a mutation which has increased the risk for cancer.

Displaying certain birth defects: There is a high connection between Wilms’ tumor and birth defects specific to certain syndromes, such as:

WAGR - This syndrome stands from (1)Wilm’s tumor, (2) aniridia (complete or partial missing of the iris -the colored portion - of the eyes) (3) genitourinary abnormalities (such as kidneys, urinary tract, penis, scrotum, testicles, clitoris, or ovaries defects), and (4) mental retardation. Children that suffer from this syndrome have a 3 percent chance for developing Wilms' tumor.
Beckwith-Wiedemann syndrome - This is a congenital growth disorder (present at birth) that causes larger body size, large organs, and impaired body functions. Children with this symptom have larger internal organs (larger than normal), a larger tongue, an oversized arm or leg, or other parts of the body (condition called hemibinhypertrophy). Children with Beckwith-Wiedemann syndrome are at higher risk for developing Wilms' tumor.
Denys-Drash syndrome -This syndrome is characterized by the absence of the penis, testicles, and scrotum. Children that suffer from this syndrome develop kidney problems and the kidney may fail to function.

Abnormalities of the genitals or urinary system:

Cryptorchidism is a medical condition where one or both testicles do not descend from the scrotum.
Hypospadias is a medical condition where the urethral (the urinary opening) is not in its normal position at the tip of the penis, but underneath.

Article by Alina Morrow, MS
Medical Writer
OmniMedicalSearch.com