Abstract

We have evaluated aspects of the EGF receptor content of four human cell lines derived from patients with previously untreated carcinoma of the cervix. Scatchard analysis revealed that three of the lines possessed approximately 2×10⁵ low-affinity and 2×10⁴ high-affinity receptors, whereas the fourth line had approximately 9×10⁴ low-affinity receptors and 9×10³ high-affinity receptors. Immunocytochemical staining using the monoclonal antibody EGFR1 showed wide intra- and inter-line variation in staining intensity. Flow cytometric analysis of EGFR1 demonstrated a fivefold difference in staining intensity between lines. Thirteen cloned derivatives of one of the lines exhibited a 200% variation in EGFR1 staining intensity. There were no differences in radiosensitivity in four of the cloned lines with different EGF receptor levels. Southern blotting analysis did not reveal any rearrangement or amplication of the EGF receptor gene. These three different methods for determining receptor content produced variations in the ranking of receptor number across the four cell lines. These studies with cervix carcinoma cell lines demonstrate the presence of varied levels of EGF receptors according to the methodology used. This may reflect differences in biological characteristics of the cell lines evaluated.