Notably, Kitai et al. reported that in epithelial-like KRAS mutant lung cancer cell lines, feedback activation is mainly driven by the EGFR pathway, whereas in mesenchymal-like KRAS mutant lung cancer cell lines, the FGFR1-FRS2 pathway plays a crucial role in the feedback reactivation of MAPK and the upregulation of AKT signaling. The gene discussed is FRS2; the disease is lung carcinoma.