Phosphospecificity: Whole cell extracts of control (co), PMA, Sorbit (So) or pervanadate treated (VH) SKOV-3 tumor cells were applied to SDS-PAGE (ca 20.000 cells per lane) and transferred to a PVDF membrane. The immunoblot was probed with mab EGFR - 5F10 (0.5 ug/ ml) for 1h at RT and developed by ECL (exp. time: 30 sec).