HDAC2 and breast cancer: Herein, we uncovered a ceRNA mechanism of ARAP1-AS1-miR-2110-HDAC2 in BC cells, among which miR-2110 has been identified as an onco-suppressor in in neuroblastoma [34] and HDAC2 is a well-recognized transcriptional co-repressor that plays a carcinogenic role in BC progression [35–37].