Lessons from the deep study of rare tumours

Next-generation sequencing technologies are having an enormous impact on mapping mutations in cancer. However, it is unclear to what extent mutations in genes are shared between cancer types, and to what extent these are unique to different cancers. While the mapping of mutations is almost saturated in common cancer types, the study of rare tumours offers surprising insights into pathways that are deranged in cancer. The paper by Amary et al. in this issue of the Journal of Pathology illustrates the value of studying uncommon cancer types. The authors report on a startlingly high incidence of IDH1/2 mutations in cartilaginous tumours. This finding not only represent a major step forward in mapping the molecular pathogenesis of these tumours, but provides further evidence of the intriguing roles of metabolic pathways in carcinogenesis. Copyright (C) 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.