However, it is reported that bone matrix proteins are found in breast cancer tissues, and calcification in calcium and phosphorus deposition environment formed by bone matrix protein metabolism is associated with positive expression of ER, PR, and HER-2.[19,20] The amount and size of calcification are closely related to the malignant degree of breast cancer and can be used as an important characteristic index for the diagnosis of breast cancer. This evidence concerns the gene PGR and breast cancer.