Interestingly, we found that knockdown of exosomal circRNA-100,338 could significantly suppress tumor growth (Fig. 5b-c), microvessel density (Fig. 5d), MMP9 expression levels (Fig. 5e), and reduce the number of lung metastatic nodules (Fig. 5f) and the positive rate of Ki67 in lung metastatic nodules (Fig. 5g) of the nude mice models (Additional file 6). Here, MMP9 is linked to neoplasm.