MAPK3 and cancer: Here, as outlined in the schematic in Figure 7, we show that dabrafenib, a drug which targets the ERK1/2 cascade for cancer and inhibits Raf→ERK1/2 signalling in the heart (Figures 1 and 2), may be useful to reduce cardiac fibrosis in hypertensive heart disease and, although there is concomitant suppression of cardiomyocyte hypertrophy (potentially because of the reduced workload imposed by increasing cardiac fibrosis), this does not appear to be detrimental to the heart either in an acute (Figures 2 and 3) or chronic (Figures 4 and 5) setting.