Objective      To explore the clinical value of the expression of thyroid transcription factor-1 (TTF-1) and surfactant protein-A (SPA) in predicting epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma.       Methods      A total of 235 patients with lung adenocarcinoma who were examined for EGFR mutations from January 2005 to November 2011 in Henan Province Tumor Hospital were enrolled

and 120 patients had paraffin-embedded lung tissue specimens. The expression of TTF-1 and SPA was detected by immunohistochemistry. The correlation of the TTF-1 and SPA expression with EGFR mutations and clinical features in lung adenocarcinoma were analyzed.       Results      There were 103 patients with EGFR mutations in exon 19 or 21 (43.8%

103/235)

and 50 patients with EGFR mutations in the 120 patients. TTF-1 expression was significantly associated with female (P=0.029)

non-smokers (P=0.025) and stage Ⅰ-Ⅱ lung adenocarcinoma (P=0.044). EGFR mutation was commonly detected in the patients with TTF-1 or SPA (P=0.043) positive expression

but was rarely found in the patients with TTF-1 negative expression (P=0.004). The negative predictive value of TTF-1 expression for EGFR mutations was 92.6%. TTF-1 expression was correlated with SPA expression (r=0.380

P=0.005).       Conclusion      The expression of TTF-1 and SPA in lung adenocarcinoma helps predict EGFR mutations

and the patients with negative expression of TTF-1 and SPA have few EGFR mutations. The expression of TTF-1 is closely correlated with SPA expression.