CA4 and cancer: The previous studies reported 1 μmol/l CA4P (equivalent to 316 ng/ml CA-4) for 15 min obviously inhibited human lens epithelial cells24, and IC50 of 1.9–835 nmol/l CA-4 (equivalent to 0.6–263.84 ng/ml) showed against various human cancer cell lines and a MDR-resistant cancer cell line6.