As shown in Fig. 9, exosomal lncRNA SND1-IT1 secreted from GC cells could competitively absorb miR-1245b-5p and simultaneously recruit DDX54 to up-regulate USP3 expression, thus mediating SNAIL1 deubiquitination and inducing the malignant transformation of GES-1 cells. Here, USP3 is linked to gastric cancer.