MIR143#12 exerted potent anticancer effects on colorectal cancer cells with or without KRAS mutations by inhibiting the KRAS signaling network in a complex manner that involved repression of not only KRAS, but also AKT, ERK, and SOS1. Because KRAS inhibitors still inhibit only one mutation,23 MIR143#12, which targets other KRAS mutations, is a promising therapeutic agent. The gene discussed is SOS1; the disease is colorectal cancer.