To determine whether cancer patients with tumor suppressor gene abnormality survive for a shorter time when their growth was stimulated by growth factors, we examined 290 non-small cell lung cancer (NSCLC) specimens for p53 and epidermal growth factor receptor (EGFR) protein expressions using immunohistochemical staining. The distribution of cases by pathological stage of tumor was 155 cases of stage I, 30 cases of stage II, 96 cases of stage III and 9 cases of stage IV. Pathological types were 142 adenocarcinomas, 127 squamous cell carcinomas, 17 large cell carcinomas and 4 other types of malignancy. Immunohistochemical staining was performed on the formalin fixed, paraffin-embedded materials with monoclonal antibodies DO-7 and clone EGFR.133. positive staining for EGFR was seen in 124 (42.8%) cases. More EGFR positive cases were found in squamous cell carcinomas than in non-squamous cell carcinomas (p=0.0121). Staining for p53 protein was observed in 147 (50.7%) specimens. Multivariate proportional hazard model analyses revealed EGFR protein expression as a risk factor in the patients with NSCLC (p=0.0240). Patients negative for both EGFR and p53 survived for a longer period of time (p=0.0427).