The expression of TTF-1 and Napsin A in early-stage lung adenocarcinoma correlates with the results of surgical treatment.

Non-small cell lung cancer (NSCLC) accounts for 80 % of lung cancers, and lung adenocarcinoma (ADC) is one of the main types of NSCLC. Although there are several studies on the relationship between lung ADC immunohistochemical diagnostic markers (thyroid transcription factor 1 (TTF-1) and Napsin A) and survival, some aspects of those studies could be improved. We examined the significance of the commonly used lung ADC diagnostic markers, including TTF-1, Napsin A, and CK7, in the prognosis of early-stage lung ADC. One hundred and nineteen cases of early-stage lung ADC (N0) were selected from the prospective database of lung cancer (Jan 2000 to Dec 2009). The expression levels of TTF-1, Napsin A, and CK7 in inventoried specimens were analyzed using tissue microarray (TMA) and immunohistochemical (IHC) analysis, and the effect of the expression level of each marker on patients' survival was examined. The diagnostic sensitivity and specificity of each marker for lung ADC were as follows: TTF-1, 87.0 and 90.1 %; Napsin A, 72.2 and 90.4 %; and CK7, 94.6 and 76.0 %, respectively. Patients with high expression levels of TTF-1 and Napsin A, and high co-expression levels of TTF-1/Napsin A had better survival rates than those with low levels of expression (P < 0.05). The expression levels of CK7 were not related to patients' survival. Multivariate analysis showed that the expression levels of Napsin A and TTF-1/Napsin A are independent prognostic factors for survival. The IHC detection of TTF-1 and Napsin A in specimens should be routinely performed in postoperative early-stage lung ADC patients. Its significance lies not only in the differential diagnosis, but also in determining the prognosis.