To achieve biological validation of the findings of the bioinformatic study, the expression level of ERK1/2 and phospho-ERK1/2 (p-ERK1/2) in the protein cargo extracted from exosomes derived from plasma of CRC and GC patients and of healthy donors was evaluated by Western blotting analysis (Figure 4). The gene discussed is MAPK3; the disease is colorectal carcinoma.