KRT19 and breast cancer: For example, circKRT19 expression derived from KRT19, a notch signaling regulator in breast cancer [53], is significantly associated with higher ERBB3 expression in mRNA (Wilcoxon rank-sum test, FDR < 2.2 × 10− 16) and protein levels (Wilcoxon rank-sum test, FDR = 7.91 × 10− 11) (Additional file 1: Figure S6D).