Here we have explored the consequences of synonymous mutations that cluster in KRAS. Importantly, there are clusters of synonymous mutations in other classic cancer genes in the COSMIC database (http://cancer.sanger.ac.uk/cosmic; [28], including KIT, NOTCH1, BRCA1, and CTNNB1 (ß-catenin)). The gene discussed is CTNNB1; the disease is cancer.