Genetics of childhood cancer

In the last 5 years, there has been a tremendous increase in understanding of the molecular genetics of several childhood cancers. The genes for more than 10 cancer predisposition syndromes are now cloned and the molecular basis of their functioning is being analysed. The classical model of inherited cancer predisposition being due to mutation of tumour suppressor genes is being expanded to include genes involved in DNA processing and weakly dominant oncogenes. The chromosomal translocation characteristic of specific types of sporadic tumours are yielding to the molecular knife, with the isolation of many of the genes disrupted in both leukaemias and solid tumours. Common structural motifs are seen among the proteins which are brought together by translocation to produce novel fusion proteins. Detection of translocations in solid tumours has been made simpler by the introduction of molecular techniques which do not rely on karyotyping.