While the mechanisms underlying miR-21 transcription regulation in BC have not been thoroughly elucidated, Chen and Bourguignon proposed a mechanism in which Hyaluronan and CD44 interaction induces c-Jun signaling and miR-21 expression, subsequently leading to BCL2 up-regulation and chemoresistance in the widely used triple-negative breast cancer cell line, MDA-MB-468 [44]. This evidence concerns the gene CD44 and breast cancer.