In a previous study, our group showed in operable NSCLC that, different relationships of P53 (a tumor suppressor), c-erb-B2 (an oncogene) and PGP (P-glycoprotein: a product of the multidrug resistance gene; MDR1), with the patient outcome may exist for different tumor histologies, again highlighting the heterogeneity in biological behavior [7]. This evidence concerns the gene PGP and non-small cell lung carcinoma.