EpCAM-positive cells separated from each tumor tissue vary from 88 to 100%, and fibroblast marker-positive cells were less than 15%, as illustrated in Fig. 1A. After 2–3 times of subculture, 94.48 ± 5.0% of the PDBCCs obtained from 10 breast cancer patients had EpCAM-positive and fibroblast marker-negative (EpCAM+/Fibro-) (Fig. 1B). Here, EPCAM is linked to breast cancer.