Introduction: Exosomes are 40-100 nm nano-sized extracellular vesicles, released from many cell types into the extracellular space and transfer their component to recipient cells. We recently reported the method to collect exosomes from cell lysates and human serum by a spin column-based method in in a relatively short time, and the clinical significance that MYO15A was significantly upregulated in exosomes from renal cell carcinoma (RCC) patient’s sera compared with normal controls. In this study, we focused on one of long non-coding RNAs, BCYRN1, in RCCs. Methods: Bioinformatic analysis was performed about clinical significance of BCYRN1 by using the database of The Cancer Genome Atlas (TCGA). Then, we performed RT-qPCR analysis of exosomes from clinical patients’ sera. Loss of function assays were performed in RCC cells (786-O, A498) on cell proliferation, cell migration and cell invasion in vitro and in vivo. Results: The analyses with TCGA database indicated that high expression of BCYRN1 was significantly associated with a poorer outcome in RCC. RT-qPCR analysis of exosomes from clinical patients’ sera showed that BCYRN1 was significantly upregulated (p = 0.0134) in RCC patients (n = 35) compared to that in healthy controls (n = 19). Moreover, BCYRN1 expression in patients with =T2a (n = 9) was significantly higher (p = 0.0404) than that in =T1b (n = 25). Loss-of-function study by using si-RNAs of BCYRN1 suppressed proliferative, migratory, and invasive activities in RCC cells. In addition, BCYRN1 knockdown inhibited tumor growth in xenograft assay. Conclusions: It was suggested that exosomal BCYRN1 can be a novel diagnosis marker, and that BCYRN1 can be a new therapeutic target in RCCs. The identification of novel target for diagnosis and therapy may lead to a better understanding of RCC and the development of new therapeutic strategies to treat this disease. SOURCE OF Funding: none
