In view of the dysregulation of sialic acid levels in bladder cancer in our previous study [27], and the essential functions of sialic acids in a variety of physiological and pathological processes [4], lectin blotting of sEV was performed, revealing that α2,3- and α2,6- sialic acids, recognized by lectins MAL-II and SNA respectively, were present on the YTS-1 derived sEV (Fig. 1D). Here, SNAI1 is linked to urinary bladder cancer.