Influence of farnesyl transferase inhibitor treatment on epidermal growth factor receptor status

Abstract The radiolabelled growth factor [ 123/125 I] I-hEGF is evaluated in vitro and in vivo to monitor the acute effects on the EGFR of R115777, a farnesyl transferase inhibitor (FTI). Upregulation of the EGFR after incubation with R115777 correlated linearly with FTI induced acute growth inhibition. Receptor mediated [ 125 I] I-hEGF internalization decreased following R115777 treatment. Preliminary data suggest that the net in vivo effect is a decrease of [ 123 I] I-hEGF uptake in the tumour. These findings suggest the possible use of radioiodinated hEGF as a radiodiagnosticum to investigate EGFR status changes as a predictor for eventual FTI chemotherapy outcome in vivo .