Here, interesting connections were found between CCL2-CCR2 and estrogen responsiveness and activities: CCL2 activated estrogen receptor α (ERα) through PI3K/Akt/mTOR signaling to elevate breast tumor cell division (41); another facet of CCL2-estrogen interactions was revealed when stimulation of luminal-A breast tumor cells by estrogen has led via twist activation to elevated production of CCL2, then giving rise to increased proliferation of the cancer cells (42). Here, ESR1 is linked to cancer.