To validate the SU–SD signature ex vivo, we selected five genes (HEYL, ACTA2, TPM2, CALD1, and TAGLN) that are expressed at the protein level in gastric tumors as defined in the Human Protein Atlas (https://www.proteinatlas.org/ (accessed on 10 January 2019)). Here, ACTA2 is linked to gastric neoplasm.