MAP2K1 and breast cancer: It has been reported that ZFX knockdown in diverse tumor types including gliomas [17], NSCLC [20], LSCC [7], breast cancers [19], and gastric cancer [13] all led to hypophosphorylation of Akt, extracellular signal-regulated kinase 1/2 (ERK1/2), or MEK1/2 except for ERK2 hyperphosphorylation in breast cancer cells [19].