It is believed that some rhabdomyosarcoma tumors begin developing in the fetus. Rhabdomyoblasts are the cells at the initial stages of development of an unborn baby. These cells will mature and develop into muscles. There has been much research into the gene structure of these rhabdomyoblasts and possible detection of a gene error that can produce the disease later in development.
Rhabdomyosarcomas usually have some type of chromosome abnormality in the cells of the tumor, which are responsible for the tumor formation. In children with an embryonal rhabdomyosarcoma, there is usually an abnormality of chromosome 11. In alveolar rhabdomyosarcoma, a rearrangement in the chromosome material between chromosomes 2 and 13 is usually present. This rearrangement changes the position and function of genes, causing a fusion of genes referred to as a fusion transcript. Patients have an abnormal fusion transcript involving two genes known as PAX3 and FKHR. This important discovery has led to improvements in diagnosing rhabdomyosarcoma.
Rhabdomyosarcomas are also more common in children with neurofibromatosis or Li-Fraumeni syndrome, which are genetic disorders. Li-Fraumeni syndrome is a clustering of soft tissue and other cancers in a family caused by mutations in a tumor suppressor gene called p53, which results in uncontrolled cell growth.
There has been no association between rhabdomyosarcoma and environmental exposures.