Lung cancer tissues from 68 patients were examined for epidermal growth factor 
(EGF) receptor levels and EGF receptor gene copy numbers. Histologic cell types 
of these lung cancer tissues included squamous-cell carcinoma (n = 30), 
adenocarcinoma (n = 28), large-cell carcinoma (n = 4), and small-cell carcinoma 
(n = 6). Tissues of squamous-cell carcinoma exhibited exceptionally high 
125I-EGF binding activity, and those of small-cell carcinoma showed no EGF 
binding activity. Southern blot hybridization analysis revealed EGF receptor 
gene amplification in the squamous-cell carcinomas with high EGF binding 
activity. The EGF receptor levels in squamous-cell carcinomas and 
adenocarcinomas were compared with their pathological staging grouping and 
pathological findings, including degree of differentiation, diameter of tumor, 
and lymph node metastasis. However, unlike previous reports on breast and 
bladder cancers, there was no obvious correlation between these pathological 
characteristics and the EGF receptor levels of lung cancer.