A growing number of studies have shed light on the role of small extracellular vesicles (sEVs), including exosomes, in colorectal cancer (CRC). Available data regarding the clinical significance of molecular players in CRC, implicated in sEVs biogenesis, is limited. In this study, we assessed the expression of the most important genes which are implicated in sEVs biogenesis and their association with sEVs plasma levels, investigated with a double sandwich ELISA assay, as well as with the clinical outcome of patients with CRC. Our study shows that RAB27A, RAB27B, RAB2B, and RAB3B mRNA levels were lower in tumor tissues compared to tumor adjacent, non-malignant tissues (p < 0.001, p = 0.009, p = 0.011, and p < 0.001, respectively). In addition, high tumor expression of RAB27A, RAB27B, RAB9A, RAB11B, and STX1A was favorable of a 5-year survival (p = 0.038, p = 0.015, p = 0.008, p = 0.002, and p = 0.028, respectively). Furthermore, patients with adenomas had lower overall plasma sEVs concentrations, compared to healthy volunteers (p = 0.026), while no statistically significant differences were observed in the overall or tumor-derived plasma sEVs concentration (p = 0.885 and p = 0.330, respectively) of CRC patients. In conclusion, sEVs biogenesis has a potentially significant role in CRC, with RAB27A, RAB27B, RAB9A, RAB11B, and STX1A having a promising role in survival outcomes.
Keywords: colorectal cancer; exosomes; expression; sEVs; survival.