PGR and cancer: Treatment of ER + PR + , HER2 + , and TN cancer cell lines with non-toxic concentration of either JQ1 or IBET151 (Fig. S3B) had the following effects on gene expression levels (Fig. 3): We observed a reduction on NSMCE2 RNA in all cell lines treated with BET inhibitors, confirming regulation of NSMCE2 by SEs.