LDHA and breast cancer: Studies of the normal breast tissue show that about 6% of the epithelial cells in the TDLU were ALDH+ and these cells can generate mammospheres in the suspended culture condition.13 Another subset of normal breast stem cell was found that are keratin K19 negative and the part of these cells increased under proliferative conditions such as epithelial hyperplasia; so, they can be the origin of breast cancers.14