OBJECTIVE To investigate the correlations between the expression of thyroid transcription factor-1 (TTF-1) and apoptosis and angiogenesis in lung carcinomas.METHODS A 829 microarray of the paraffin tissue chips was constructed, which contained 196 lung carcinomas, 10 normal lung tissues, and 1 muscular tissue. Terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL) and immunohistochemical SP method were used to detect apoptosis and expression of TTF-1 and CD34 in different types of lung carcinomas. A Leica Q500 MC image analysis system was used to measure and calculate TTF-1 positive unit (PU), apoptotic index (AI) and microvessel density (MVD).RESULTS AI of lung small cell carcinoma and large cell carcinoma were smaller than those of lung adenocarcinoma and squamous cell carcinoma (P = 0.000). AI of lung carcinomas with lymph node metastases was smaller than that of those without (P = 0.039). AI of lung carcinomas in TNM stage I-W was smaller than that in stage Ⅰ (P = 0.008). The PU of the TTF-1 was negatively correlated with AI in small cell lung carcinoma (r = -0.752, P = 0.000). MVD of lung carcinomas without lymph node metastases was smaller than that of those with lymph node metastasis (P= 0.031). MVD of lung carcinomas in TNM stage Ⅰ was smaller than that in stage Ⅰ-Ⅳ (P -- 0.040). The PU of TTF-1 was positively correlated with MVD in lung adenocarcinoma (r = 0.708, P = 0.000).CONCLUSION There is a negative correlation between TTF-1 PU and AI in small cell lung carcinoma. TTF-1 PU and AI may be correlated with each other. There is a positive correlation between TTF-1 PU and MVD in lung adenocarcinoma. TTF-1 may induce the development of lung adenocarcinoma by inducing tumor angiogenesis.