TTF-1 Expression And Its Diagnostic Application In Lung Carcinomas

Objective To detect the expression of thyroid transcription factor 1( TTF-1) and study its application in the diagnosis and prognosis of lung carcinomas.Methods Of 127 Formalin-fixed, paraffin-embedded tissue samples ,79 were primary lung carcinomas including 34 squamous cell carcinomas,22 adenocarcinomas,4 big cell carcinomas, 19 small cell lung cancers (SCLC) ,29 were metastatic carcinomas,and 36 non-carcinomas tissues. Expression of TTF-1 was detected by immunohistochemistry. The expression level of TTF-1 was graded as , + :5 % to 10 % of tumor cells positive, + + : 10 % to 50 %, + + + : > 50 %.Results The positive nuclear immunoreactivity of TTF-1 was identified 48% in lung carcinomas , 17.6% in squamous cell cancer (SCC) ( P < 0. 05) . The positive expression rate of TTF-1 in lung adenocarcinomas (ACs) was 72% (31/ 42). There was no correlation between TTF-1 expression and ACs differentiation or ACs subtypes ( P > 0. 05) . All but one (thyroid follicular carcinoma) metastatic ACs were TTF-1 positive. Mesenchymal component and lymphoid or inflammatory cells were consistently TTF-1 negative.The positive rate of TTF-1 expression in poor differentiations,TNM stageⅢ～Ⅳand with lymph node metastasis was higher than in well differentiations,TNM stageⅠ～Ⅱand no lymph node metastasis.Conclusion A significant difference of TTF-1 expression may assist in distinguishing lung carcinomas from TB , lymphoma or inflammatory lesions. Owing to its restrictive expression in lung tissue , TTF-1 might be used to differentiate primary from metastatic adenocarcinoma of the lung. And be used as markers of prognosis of lung carcinomas in clmical practice.