NARS1 and breast cancer: However, after disruption of the CmPn signaling network under mPR-specific PRG actions, expression of HDAC1 was observed to be down-regulated (Fig. 8, panel A1), while NARS was significantly up-regulated in nPR(+) T47D cells (Fig. 8, panel A1), preliminarily classifying these genes as mPR-responsive biomarkers in Luminal-A breast cancer cells.