Virus linked with brain tumour

A virus that commonly lies dormant in children could be responsible in the formation of medulloblastomas, which are fast growing malignant childhood tumours. Some medulloblastomas contain one or two proteins from a virus called the JC virus. Medulloblastomas are the second most common type of brain tumours accounting for approximately 20% of the cases. They are fast growing, spread widely throughout the body causing death in more than half the cases. Radiation exposure and certain genetic diseases are known to put children at risk, but in most cases the cause of medulloblastomas is a mystery. According to researchers at Temple University, USA most people infected with JC virus are relatively healthy and are able to fight off the virus. However, in some cases, the virus is able to infect the cells in the brain, which can turn into a medulloblastoma. They have been studying the JC virus for almost 20 years, because in people with weak immune systems, such as those with AIDS, it is known to lead to a fatal nervous system disease. They sampled tumour tissue taken from 20 children who had died of medulloblastoma. They found 65 percent of the samples contained some genes from the JC virus. Children are usually infected with this virus by age 14, but in most cases the infection goes unnoticed because it does not cause illness. It is still unknown why the virus sometimes affects the brain cells causing them to turn cancerous. Also, studies show that monkeys and other primates do not develop medulloblastomas when they are infected with JC virus. However further research is required to the presence of JC virus in normal brain tissue as well as in other types of brain tumours.

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