circRNA expression profiles in TNBC. a. The cluster heat map showed the differentially expressed circRNAs over 3-fold change. Red color indicates high expression level, and green color indicates low expression level. The black arrow indicates circGFRA1. b. The scatter plot was used for assessing the variation in circRNA expression between TNBC cell lines and HME cell line. The values of x and y axes in the scatter plot were the normalized signal values of the samples (log2 scaled). The green lines are fold-change lines. c. The top 10 upregulated circRNAs were shown. d. qRT-PCR was performed to verify the expression of the top eight upregulated circRNAs. All the data are shown as the mean ± s.e.m.