PARL and colorectal cancer: The potential of rhomboid inhibitors in pharmacologically relevant settings has yet to be proven, but it currently seems that inhibitors of Plasmodium rhomboids might be therapeutic for malaria (Baker et al., 2006, Lin et al., 2013), inhibitors of the human mitochondrial rhomboid protease PARL might stimulate mitophagy (Meissner et al., 2015) and thus be disease-modifying in the context of Parkinson's disease (Chan and McQuibban, 2013), and inhibitors of human RHBDL4 could be targeting EGF receptor signaling by transforming growth factor α in colorectal cancer (Song et al., 2015).