ACTA2 and esophageal squamous cell carcinoma: Since signatures greatly vary depending on the tissue of origin [33]–[34] and since no ESCC-associated CAF markers have been identified so far, we selected 4 markers that have been found to be either ‘general’ CAF markers or oral/esophageal CAF markers [33], [35]–[37]: ACTA2 (or alpha-SMA), FAP, S100A4 (or FSP1) and CSPG4 (or NG2).