MUC19 and breast cancer: The results suggested that circ_0001982 knockdown reversed the elevated mRNA and protein levels of MUC19 in BC cells in hypoxia conditions, and miR-1287-5p inhibitor partly reversed the effects of si-circ_0001982 on MUC19 mRNA and protein levels, suggesting that circ_0001982 upregulated MUC19 expression by sponging miR-1287-5p (Fig. 10A–D).