Examples of flow cytometric measurements showing the percentage of viable B-ALL cells cultured alone and cocultured with hBM-MSCs in absence or presence of neutralizing Notch receptor Abs and GSI XII. B-ALL cells were cultured alone or cocultured with hBM-MSCs (10:1 ratio) in absence or presence of anti–Notch-1/-3 and -4 Abs and GSI XII for 3 days. Percentage of viable B-ALL cells was measured by annexin V⁻/7-AAD⁻ (bottom left quadrant) flow cytometry after electronic gating on CD19⁺ cells in 2-color flow cytometric analysis.