EGFR and malignant colon neoplasm: Using human colon cancer cells that express high levels of M3R, we showed that muscarinic agonist-induced cell proliferation is mediated by cross-talk between M3R and epidermal growth factor receptors (EGFRs) and activation of post-EGFR signaling mediated by p44/42 mitogen-activated protein kinase (ERK) [6,7].