AGR2 and breast cancer: Thus, circDOCK1-1 may increase the expression of AGR2, ENPP1, and PPP1R9A transcripts via a sponging effect exerted on hsa-mir-539-3p, hsa-miR-545-3p, and/or some of the other microRNAs identified in Table S5 Clearly, further functional studies are needed to confirm the hypothesized molecular mechanism of action and the potential involvement of microRNAs in the process of epithelial differentiation activated by circDOCK1-1 in TNBC-mes breast cancer cells.