RESUMEN
<p><b>OBJECTIVE</b>To evaluate serum Nkx2-1 (NKX homeobox-1) levels in diagnosis of primary lung cancer.</p><p><b>METHODS</b>The serum NKX2-1 and CEA (carcinoma embryonic antigen) levels were measured in 61 patients with primary lung cancer admitted from May 2009 to December 2010 and 49 healthy individuals served as controls. The receiver operating characteristic curve (ROC) of NKX2-1 in diagnosis for primary lung cancer was analyzed. The value of serum NKX2-1 in diagnosing primary lung cancer was compared with that of CEA by X(2) test and Kappa test.</p><p><b>RESULTS</b>The serum Nkx2-1 levels in lung cancer were significantly higher than those in controls [(1.4206 ±0.1257)ng/ml compared with (0.7646 ±0.0734)ng/ml,P<0.01]. ROC analysis showed the area under the curve of serum NKX2-1 was 0.859. The Kappa value of NKX2-1 was higher than that of CEA (0.586 compared with 0.396,P<0.05). Combination of serum NKX2-1 with CEA improved the Kappa value to 0.704, and also had high sensitivity (83.6%) and specificity (87.0%) for diagnosis of primary lung cancer.</p><p><b>CONCLUSION</b>Serum NKX2-1 protein can be used as a marker for diagnosis of lung cancer, the combination of NKX2-1 with CEA may further improve the diagnostic value.</p>