EFNA1 and gastric cancer: To determine whether EphA2 receptor is required for the functions of Ephrin A1 in regulating EMT and metastasis of gastric cancer cells, we constructed EphA2 knockout (KO) cell line by CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 system in MKN45 (Fig. 2C) and AGS cells (Fig. EV4B,C) and tested the EMT and metastasis abilities regulated by Ephrin A1.