CD63 and breast cancer: We observed a significant difference of CD63 protein levels between two groups of exosome samples derived from healthy people and cancer patients p < 0.01 for hepatocellular carcinoma patients, p < 0.001 for gastric carcinoma patients, p < 0.001 for breast cancer patients, p < 0.0001 for colon cancer patients, p < 0.001 for ovarian cancer patients, p < 0.001 for pancreas carcinoma and p < 0.0001 for prostate cancer patients) (Figure 3).