CD24 and breast cancer: Using immunohistochemistry, a series of studies has revealed that CD24 was expressed in a variety of human malignancies, such as nasopharyngeal carcinoma, non-small-cell lung cancer, breast cancer, hepatocellular carcinoma, pancreatic cancer, colorectal cancer, renal cell carcinoma, bladder carcinoma, ovarian cancer, prostate cancer and intrahepatic cholangiocarcinoma [16], [17].