FLT4 and esophageal squamous cell carcinoma: On the basis of the literature [20], we tested the influence of ESCC-derived exosomes on the expression of lymphangiogenesis-related markers (VEGF-C, VEGF-D, VEGFR3, LYVE-1, podoplanin, PROX1) in HLECs at the same time, which showed that they were increased under KYSE30-Exos treatment, and the increase was more significant under EC109-Exos treatment (Fig. 2F, G).