That is why we conducted the real-time PCR test to confirm that ECSCs, whether from OE33 cells or samples of esophageal cancer tissues, have significantly high expression of CXCL12 (Figure 2E); ELISA also confirmed the autocrine secretion of CXCL12 by ECSCs (Figure 2F). This evidence concerns the gene CXCL12 and esophageal cancer.