Background: The EGF receptor/ligand system seems to be involved in the regulation of gastric mucosa proliferation and progression of gastric carcinomas.
Patients and methods: EGF receptor levels were quantitatively determined in 47 gastric carcinomas by 125J [EGF] radioreceptor assays in membrane preparations of tumor samples or corresponding adjacent mucosa. Specific receptor binding was determined by the analysis of displacement curves by non-linear least-square regression analysis using an estimated model of 'goodness of fit'.
Results: Increased EGF receptor binding was observed in gastric carcinomas (mean +/- SEM: 11.87 +/- 1.9 fmol/mg protein) in comparison to adjacent normal gastric mucosa ( 5.28 +/- 1.0 fmol/mg protein, p = 0.003). Elevated EGF receptor levels were especially found in more invasive T3/4 carcinomas, tumors with positive lymph nodes, advanced UICC III carcinomas, undifferentiated tumors, carcinomas of the diffuse-type according to Lauren's classification and gastric carcinomas localized distal from the cardia. In histopathologically normal appearing gastric mucosa, EGF-receptor levels were significantly decreased relative to corresponding tumor samples from advanced UICC stages (UICC I vs UICC I/II: p = 0.008) or tumors with low levels of differentiation (G2 vs G3: p = 0.028). Overall survival was significantly reduced in patients with advanced gastric carcinomas according to UICC classification (UICC III vs UICC I/II: 18.8 vs 45.5 months, p = 0.016). A subgroup analysis of gastric carcinomas localized distal from the cardia indicated, that increased EGF-receptor levels were an independent indicator of poor prognosis as determined by univariate (p = 0.020) and multivariate analysis (p = 0.042).
Conclusion: Gastric carcinomas with increased EGF receptors might be a possible target for anticancer strategies blocking the EGF receptor/ligand pathway.