In fact, byanalyzing the logistic regression controlled for tobacco history, histologicaltypes, and staging, we observed that the concentration of sputum CFL1 was anindependent predictor of risk of lymph node metastases in patients with lung cancer.These results indicate that the concentration of this protein in sputum is relatedto tumor progression, probably as a consequence of modifications in theextracellular matrix (ECM) earlier in the carcinogenesis process, i.e., at the stageof neoplastic transformations. This evidence concerns the gene CFL1 and lung cancer.