Fig. 1

Analyses of circKIF18B_003 expression in PCa. A Schematic illustration of circKIF18B_003 formation via circularization of exons 2–7 of the KIF18B gene. Divergent (upper panel) and convergent (lower panel) primers were designed to verify circKIF18B_003. B Using RT-qPCR and agarose gel electrophoresis, the existence of circKIF18B 003 was confirmed. Total RNA extracted from DU145 cells (upper panel) or PC-3 cells (middle panel) with or wither RNase-R treatment were subjected to polymerase chain reaction. The products conducted by divergent primers of circKIF18B_003 was subsequently validated by Sanger sequencing (lower panel), and the red arrow confirmed the “head-to-tail” splicing of circKIF18B_003 in PCa cells. C The relative expression level of circKIF18B_003 was evaluated in the RWPE-1 cell line and different PCa cell lines, including DU145, PC-3, and LNCaP lines. D The relative expression of circKIF18B_003 level in 78 PCa tissues and 23 benign prostatic hyperplasia tissues was analyzed by RT-qPCR. Mann–Whitney U test was used for the statistical analyses. E The relative expression level of circKIF18B_003 in PCa tissue and the average expression level of circKIF18B_003 in 23 cases of benign prostatic hyperplasia tissues were compared and analyzed. F Kaplan–Meier method was used to demonstrate the biochemical recurrence survival curve and log-rank test was used to analyze the survival data. G The area under the curve in determining the efficacy of the model in predicting the biochemical recurrence survival of PCa patients. Student’s t-test was used for the statistical analyses. ^*P < 0.05; ^***P < 0.001