ALDH1A1 and neoplasm: For example, 4.3%, 29.2% and 38.8% of breast, ovarian and colon cancer specimens highly expressed ALDH1 (between 75 to 100% of tumor cells were ALDH1 positive, Figure 2C), however, none of the tumor cell lines were composed of greater than 75% of ALDHbr cells (Table S1).