Fig. 1

Expression profiles of circRNA and the correlation between hsa_circ_0000231 and poor prognosis of CRC. A The cluster heat maps displayed the increased and decreased circRNAs. Each column indicates a sample while each row indicates an individual circRNA. The red and green strips represent high and low expression, respectively. B The volcano plot visualizes the expression of circRNA between CRC tissues and adjacent. The red dot on the left represents the significantly high expression of circRNAs in adjacent normal tissue. The red dot on the right represents the significantly high expression of circRNAs in CRC. C Classification of differentially expressed circRNA between CRC tissues and adjacent. D qRT-PCR assay was used to verify the results of circRNA microarray assay. The result shows that hsa_circ_0000231 has the largest fold change. E Relative expression of hsa_circ_0000231 in CRC cell lines was determined by qRT-PCR. The results showed that the expression of hsa_circ_0000231 in CRC cell lines were significantly higher than that in NCM460 cells. F Relative expression of hsa_circ_0000231 in CRC tissues (CRT) and adjacent normal tissues (CRN) was detected by qRT-PCR (n = 160). The result showed that the expression of hsa_circ_0000231 was higher in tumor tissues than in adjacent normal tissues. **p < 0.001. G Kaplan–Meier survival curve of overall survival in 160 patients with CRC according to the hsa_circ_0000231 expression. Patients were divided into high expression and low expression group by median expression. Patients with high expression of hsa_circ_0000231 in CRC had significantly shorter OS, with statistically significant differences. H Kaplan–Meier survival curve of progression-free survival in 160 patients with CRC according to the hsa_circ_0000231 expression. Patients were divided into high expression and low expression group by median expression. Patients with high expression of hsa_circ_0000231 in CRC had significantly lower DFS, with statistically significant differences