Results from the xiantao database revealed that GCG and IGF1 had lower expression levels in oesophageal cancer than in normal tissues (Fig. 4C, p < 0.05), whereas FBN1, COL5A1, COL1A1, THBS1, MMP9, MMP2, IL6 and POSTN showed the opposite trend (Fig. 4C, p < 0.05). Here, GCG is linked to carcinoma of esophagus.