Figure 1. circRNA_141539 was up-regulated in ESCC tissue. (A) Hierarchical clustering analysis showed the top 10 most up-regulated and down-regulated circRNAs. The expression levels are presented in different colors indicating expression levels. (B, C) qRT-PCR assay showed that circRNA_001937 was significantly up-regulated in ESCC tissues (n=50), *P < 0.05, **P < 0.01 versus corresponding adjacent tissues. circRNA_141539 expression levels were normalized to GAPDH. N: adjacent normal tissues, C: ESCC tissues.