A multitude of evidence revealed that distinct exosomal proteins, e.g., Rab, GTPases, ESCRT, CD9, CD81, CD63, flotillin, TSG101, ceramide, Alix, tetraspanins, and integrins, could be used for cancer detection and consideration of clinical outcomes in cancer patients [7] (Table 2). The gene discussed is CD9; the disease is cancer.