MMP2 and neoplasm: There were significantly more metastases, higher total fluorescence intensity, and MMP2 protein expression in ESCC xenografts in the lenti-CST1 group than in the lenti-NC group, without significant differences in the size, volume and weight of the tumor tissues, elucidating the effect of CST1 on promoting the metastasis of ESCC cells in vivo (Fig. 9A–D).