Utility of immunohistochemistry method in expression of thyroid transcription factor-1 in endometrial and endocervical adenocarcinoma

Thyroid transcription factor-1 (TTF-1) is widely used in the diagnosis of lung and thyroid carcinomas. Although there have been reports of TTF-1 immunoreactivity in tumors other than those originating from the lung or thyroid, endocervical and endometrial adenocarcinomas have not been studied in large numbers in this regard.

Thirteen endocervical adenocarcinomas, 39 endometrioid endometrial adenocarcinomas and four uterine serous carcinomas which had no neuroendocrine component were retrieved, stained by TTF-1 and examined. A semiquantitative grading system was used to evaluate the distribution of TTF-1 staining (0= negative, 1+  5%, 2+= 5% to 25%, 3+= 26% to 50%, 4+= 51% to 75% and 5+  75%). A qualitative system was also used to evaluate the intensity of TTF-1 staining (weak, moderate and strong).

TTF-1 expression was seen in 1 out of 13 (7.7%) endocervical adenocarcinoma samples, showing 1+ distribution rate and weak intensity. The positive sample was moderately differentiated. TTF-1 expression was present in 2 out of 39 (5.1%) endometrioid adenocarcinoma samples (one grade I and the other grade II) with 1+ distribution rate and weak intensity. There was no apparent correlation between the degree of differentiation and TTF-1 positivity in the studied adenocarcinomas. None of the four endometrial serous carcinomas were positive for TTF-1.

Although some recent studies cast doubt about the specificity of TTF-1 for lung and thyroid carcinoma, our study showed that TTF-1 was negative in endocervical and endometrial adenocarcinomas and established the specificity of TTF-1 for lung and thyroid carcinomas.