MTOR and columnar cell hyperplasia of the breast: Hypoxia inducible factor 1α (HIF-1α), an overexpressed factor in CCH, reduces the density of astrocytes and microglia in the cortex and hippocampus, inhibits oxidative stress and inflammation in the brain, and provokes mitochondrial autophagy, which is frequently accompanied by suppression of the mTOR signalling, thereby enhancing neuronal survival in CCH (Gong et al. 2014).