NRG1 and colorectal cancer: NRG1 mainly binds to ERBB3 heterodimer, then activates various intracellular signaling cascades, such as PI3K/Akt, JAK-STAT3, RAS, Erk1/2, etc. In addition, NRG1 has been shown to be a marker of cetuximab resistance in colorectal cancer (Luraghi et al., 2018).