The cause of cancer in children is usually unknown.
Wilms' tumors may be associated with congenital anomalies such as aniridia, hemihypertrophy, and genitourinary malformations.
Hepatoblastoma may be associated with hemihypertrophy, Beckwith-Wiedemann syndrome, hereditary adenomatous polyposis, and extremely low birthweight, but a triggering cause is rarely found. Hepatocellular carcinoma is associated more with an underlying liver disease such as, hepatitis B, neonatal hepatitis, and metabolic diseases.
An etiological association is unknown for rhabdomyosarcoma, but it is believed that genetic factors are of significance since there is an increase in incidence with the Li-Fraumeni hereditary cancer syndrome and with neurofibromatosis type 1. There is no known significant environmental factor associated with rhabdomyosarcoma.
For NRSTS, the underlying etiology is known in less than 5% of the cases. Possible associations may be previous radiation, Li Fraumeini syndrome, NF-1, and Gardner syndrome.
In most cases, the cause of osteosarcoma is unknown. Since osteosarcoma is often diagnosed in association with a pubertal growth spurt, it is reasonable to hypothesize that tumor development may be related to rapid growth of bone tissue. A small portion of osteosarcomas are caused by radiation, and the risk for developing osteosarcoma depends on the dose of radiation. Treatment with alkylating medications can also lead to osteosarcoma development. The combination of radiation, use of alkylating agents, and a genetic disposition for cancer makes osteosarcoma one of the most common forms of secondary malignancy after childhood cancer treatment. The incidence of osteosarcoma increases with certain hereditary syndromes that involve tumor suppressor genes.