CLDN1 and cancer: These exosomes are associated with alterations in normal BM-MSC, such as induction of the cancer-associated fibroblast phenotype, characterized by increased cell proliferation and production of cytokines and chemokines—including IL-8, B-cell activating factor (BAFF), C-X-C motif chemokine ligand 1 (CXCL1), leukaemia inhibitory factor, IL-6, IL-34, C-C motif chemokine ligands 2 and 5 (CCL2 and CCL5, respectively)—as well as of the migration/invasion factors claudin 1 (CLDN-1), epithelial stromal interaction 1 (EPSTI-1), ICAM-1, and matrix metalloproteinase 1 (MMP-1) [85].