NR4A1 and breast cancer: Inhibitors of ERK, MEK, Akt and mTOR are potent anticancer drugs and are currently being investigated in clinical trials or are approved, such as the MEK inhibitor trametinib, indicated for unresectable or metastatic melanoma with BRAF V600E or V600K mutation [28] or the mTOR inhibitor everolimus, whose indications include advanced hormone receptor-positive, HER2-negative breast cancer, progressive neuroendocrine tumors of pancreatic origin and advanced renal cell carcinoma [29].