AIF1 and columnar cell hyperplasia of the breast: Since we could not distinguish M1-type (classical/proinflammation activation) and M2-type (alternative/anti-inflammatory activation) simply by cellular morphology analysis, which play beneficial or detrimental roles [29], double labelling of Iba-1 with M1 marker and M2 marker is an exciting work to further explore the role of microglia in CCH in our future research.