AKT1 and neoplasm: Inhibition of Src activity attenuated RSPO2-induced EGFR/Akt phosphorylation (Figure 4G), whereas the suppression of Akt activity largely reduced the promotive effect of RSPO2 on cell proliferation (Figures S4F–S4G), suggesting that RSPO2-induced Src/Akt activation mainly accounts for tumor growth.