The study of pathological situations that seem to stem from overactivation of Erk per se, via the autoactivation mechanisms, including cancers in which the R84H mutations of Erk1 were identified (COSV107307066; cancer.sanger.ac.uk) and cases of cardiac hypertrophy (11) may also assist in resolving the mechanism of Erks' activation via T207/188 phosphorylation. This evidence concerns the gene MAPK3 and cardiac hypertrophy.