CD63 and familial pancreatic carcinoma: We find that the pancreatic cancer cells display the expected morphology on matrices of different stiffness (Supplementary Fig. S2A), the vesicle size and size distribution is independent of matrix stiffness (Supplementary Fig. S2B), the vesicles contain CD63 and TSG101 across all conditions (Supplementary Fig. S2F), and that proteins are differentially enriched in the BxPC3 EVs as a function of overall matrix stiffness (Supplementary Fig. S2H).