To establish a correlation between phenotypic response and the binding affinity of the LBD and NRR antibodies to Notch1 expressed on the surface of cancer cells, flow cytometry was performed with LS-1034, BxPC3, Colo_205, and TALL-1 cells using saturating concentrations of the WC75 (NRR) and WC613 (LBD) antibodies. The gene discussed is NOTCH1; the disease is cancer.