STAT3 and cancer: Together with the fact that mitochondrial STAT3 has been identified as a contributor to RAS-dependent cellular transformation (Gough et al., 2009), we support the idea that ERK-mitoSTAT3-mediated mitochondrial transcription might be a key process in cancer development, especially in the intestine, where we demonstrate here and in Peron et al. (2020) that cell proliferation is STAT3-dependent.