Detection of endogenous InsR: Whole cell extracts of serum starved tumor cells (20.000 cells per lane) were applied to SDS-PAGE and transferred to a PVDF membrane. The immunoblot was probed with mab InsR-9H4 (0.5 ug/ ml) for 1h at RT and developed by ECL (exp. time: 3 min). Lane 1: A431 Lane 2: SW480 Lane 3: SW620 Lane 4: HT29 Lane 5: MCF-7 Lane 6: MDA-MB231 Lane 7: T47D