SOS1 is a guanine nucleotide exchange factor (GEF) that facilitates RAS activation by catalyzing the release of guanosine diphosphate (GDP) from RAS.28, 29 Previous reports showed a positive correlation between SOS1 high expression and several cancers, such as ovarian cancer30 and hepatocellular carcinoma.31 The gene discussed is SOS1; the disease is cancer.