The importance of `silent' mutations in cancer
'Silent’ (or synonymous) mutations change the sequence of a gene without directly altering the sequence of the protein that it encodes. Through an analysis of the DNA sequences of >3000 human tumours this study - which involved three ICREA professors from the Centre for Genomic Regulation (CRG) - showed that these silent mutations frequently contribute to cause cancer in humans. The mechanisms by which these mutations function may be diverse, but it was shown that they often alter how the different parts of a gene are spliced together to encode proteins. In total, it was estimated that between 1 in 2 and 1 in 5 of the silent mutations observed in known oncogenes (cancer promoting genes) contributed to the development of a tumour. The computational methodology developed in the study also revealed that genes that cause cancer when they are overexpressed - i.e. when they produce too much protein - often harbour mutations in regulatory regions at the ends of the genes (i.e. in their 3’-untranslated regions).