Overexpression of oncoproteins in non-small cell lung carcinomas of smokers

Non-small cell lung carcinoma specimens of 173 previously untreatedpatients were analyzed for the expression of proteins encodedby the oncogenes c-myc, c-fos, c-jun, c-erbB-1, c-erbB-2, c-H-ras,c-K-ras and c-N-ras. Forty-six per cent of the tumors were positivefor the c-MYC protein, 60% for c-FOS, 50% for c-JUN, 80% forc-ERBB-1, 55% for c-ERBB-2, 12% for c-H-RAS, 5% for c-K-RASand 71% for c-N-RAS. Proteins encoded by c-fos and c-jun areover-expressed more frequently in carcinomas of smokers (c-fos:P < 0.005; c-jun: P < 0.01). When we grouped the patientsaccording to their tumor histology the results became more evident.Squamous cell lung carcinomas of smokers showed a higher incidenceof c-FOS (P = 0.01), c-JUN (P < 0.01) and c-ERBB-1 (P = 0.01)proteins than squamous cell lung carcinomas of non-smokers.The expression rate and the intensity of staining proved notto be influenced either by the number of cigarettes smoked dailyor by cessation of smoking. In adenocarcinomas, however, weonly found a trend for a more frequent overexpression of c-fos(P = 0.07) and c-jun (P = 0.14) encoded proteins in carcinomasof smokers and no correlation between the expression of c-erbB-1products and smoking. No correlation was found between the expressionof c-MYC, c-ERBB-2, c-H-RAS, c-K-RAS and c-N-RAS proteins andthe smoking habits of the patients, neither in squamous cellcarcinomas nor in adenocarcinomas of the lung.