CircRNA expression profiling in human breast cancer

We collected 3 paired tumor tissues and adjacent normal tissues collected from patients with node-positive primary breast cancer. Total RNA was extracted from tissues using Trizol reagent. Then total RNA was processed and circRNAs were profiled using RNA-seq technique. Raw read counts were filtered to remove the genes with a zero read count in 3 or more samples, and then normalized with DESeq2 in the statistical program R (version 4.0.1). Differentially expressed genes were screened using following criterions: fold change was larger than 2 and adjusted P value was less than 0.05. The circRNA expression in breast tumors was compared to circRNA expression in adjacent normal breast tissues.