Extracranial rhabdoid tumours: what we have learned so far and future directions.

Extracranial rhabdoid tumours are rare, and often occur in infants. Although the kidney is the most common site, they can occur anywhere in the body. Most contain a biallelic inactivating mutation in SMARCB1, which is part of the chromatin remodelling complex SWI/SNF, and functions as a classic tumour suppressor gene. Despite multimodal therapy, outcome in rhabdoid tumours remains poor with only 31% of patients surviving to 1 year. The young age of patients limits use of radiotherapy, which, along with age, is an important prognostic factor. Because the tumours are rare, no standard therapeutic pathway exists, and no randomised trials have examined the role of new therapeutic approaches. Improved understanding of the biology and role of SMARCB1 has enabled identification of new targets for small molecule inhibitors to combine with chemotherapy backbones that we might establish from the current EpSSG and COG studies.