ESR1 and breast cancer: Further pathway, GO, and proliferation marker enrichment analyses of the integrated diagnostic network collectively suggest two carcinogenic transitions governing breast cancer differentiation, i.e., proliferation and metastasis, and five out of 10 cancer hallmarks87, i.e., ‘enabling replicative immortality’ (i.e., cell cycle, especially G1/S and G2/M), ‘sustaining proliferative signaling’ (ER, HER2), ‘resisting cell death’, ‘deregulating cellular energetics’ (aerobic glycolysis), and ‘activating invasion & metastasis’ empowering such processes, with the first two being the most prominent.