The are few outstanding serous markers in the treatment of bronchial cancer. ACE lacks sensitivity and specificity and cannot be used as a diagnostic marker. It has been described as a marker of tumoral mass, although not in our study. Prognostic significance was observed, but only in a univariate analysis. Sensitivity of SCC TA4 varied between studies. In our population, the ROC curve for SCC TA4 showed poor discrimination potential. NSE was shown to be a useful marker in the treatment of patients with small cell cancers. Cytokeratins are expressed by all bronchial cancers. Cytokeratin 19 is a sub-unit detected in simple epithelia and their neoplastic counterparts. During tumoral cell lysis, certain fragments of this cytokeratin may be liberated. The immunoradiometric assay described here is able to detect fragments of cytokeratin 19 (called Cyfra 21-1) in serum. Our study established a correlation between Cyfra 21-1 levels and the cancer stage for NCPC, but not for CPC. In addition, Cyfra 21-1 concentration may be used as a tumoral mass marker. Patients with high Cyfra 21 levels must undergo special treatment to find remote tumors.