Cells were detached with Versene (Invitrogen) counted and resuspended in 100 µL phosphate buffered saline (PBS) containing 1% bovine serum albumin (BSA). Cells were blocked with PBS/1% BSA for 1 h on ice. Two micrograms of QUAD 3.0, EphA3 antibody (house made),9 (link) EphA2, EphB2 (R&D Systems), or IL-13RA2 (Biolegend) was added and incubated for 2 h on ice with occasional mixing. Cells incubated with isotype antibody served as controls. Cells were washed with PBS/1% BSA prior to the addition of Alexa-Fluor-labeled secondary antibodies. Cells were incubated on ice for an additional 1 h with occasional mixing. After washing with PBS/1% BSA, cells were postfixed with 10% buffered formalin. Cells were analyzed on an Accuri 6 flow cytometer. Data were analyzed using the FCS Express software (DeNovo Software).