Breast cancer is most often hormone-dependent. Hyperestrogenism leads to hypoxia, which causes anaerobic glycolysis, which produces a little energy and lactate. Progesterone plays an antagonistic role to estrogen. It also acts synergistically with estrogen in the case of EGF mutations and hypermethylation at the promoter level of tumor suppressor genes. This involves aerobic glycolysis and oxidative phosphorylation, releasing a lot of energy. This is oxidative stress. We also observe phosphorylation of lipocortin, thus disinhibiting phospholipase A2 to form arachidonic acid, which produces prostaglandins, leading to chronic inflammation that generates cancer