NMP-22 ELISA assay of human bladder cell lines. The human bladder cancer cell lines, RT4, T24 and UM-UC-14 had elevated NMP-22 levels compared to the benign UROtsa human cell line. Levels of NMP-22 in the KU-7 human bladder cancer cell line were not elevated compared to UROtsa. Significance (p < 0.05) was assessed by Student t test. n.s., not significant.