The correlation between TTF-1 immunoreactivity and the occurrence of lymph node metastases in patients with lung cancer.

AIMS AND

BACKGROUND

Thyroid transcription factor (TTF-1) is a tissue-specific transcription factor expressed in the epithelial cells of thyroid and lung. The aim of this study was to evaluate the relationship between the expression of TTF-1 and clinico-pathological parameters in pulmonary adenocarcinoma and adenosquamous carcinoma.

METHODS

Resection material of pneumonectomies and lobectomies of 39 patients was retrospectively examined. Twenty-eight patients were diagnosed with adenocarcinoma and 11 with adenosquamous carcinoma. Tumors were classified into 3 groups: a strongly positive group (++) with double dagger 50% tumor cells positive for TTF-1; a weakly positive group (+) with 1-49% positive tumor cells; and a negative group (-) with less than 1% or no positive tumor cells. Analysis was performed with Kaplan-Meier estimates and log-rank tests.

RESULTS

Staining for TTF-1 was negative in 10 cases. There was focal staining in 9 cases, while there was diffuse staining in 20 (51%) cases out of 39, and 15 (75%) of these were adenocarcinomas. There was a statistically significant association between TTF-1 and lymph node metastases (P = 0.029). No relationship was found between TTF-1 positivity and disease-free and overall survival.

CONCLUSIONS

TTF-1 expression may be a predictor of lymph node metastases. Additional work in a larger group of patients is needed to better assess the utility of this marker.