COMPARISON OF THYROID TRANSCRIPTION FACTOR-1 EXPRESSION IN GASTRIC ADENOCARCINOMA AND NON-COHESIVE TYPE GASTRIC CARCINOMA: IS THERE ANY DIFFERENCE?

ENVER VARDAR¹ , GULDIDAR BASMACI¹ , ERDEM COMUT¹ , DEMET KOCATEPE CAVDAR² , NAZIF ERKAN¹ , ENVER ILHAN¹ , BARAN UMUT VARDAR³

¹ SB Izmir Training Teaching Hospital, Pathology Department, Izmir, Turkey - ² Pathologist, SB Izmir Training Teaching Hospital, Pathology Department, Izmir, Turkey - ³ Izmir 9 Eylul University, Medicine Faculty, Radiology Department, Izmir, Turkey

Introduction: Metastasis of an unknown primary site in liver, lung, lymph nodes and soft tissue is not rare, and in these patients, immunohistochemical findings may have an effect on the therapeutic implications and prognosis. Thyroid transcription factor-1 (TTF-1) is a transcription factor which plays an important role in the normal physiology of the thyroid and lungs. TTF-1 is highly specific and sensitive in the diagnosis of certain types of primary lung and thyroid carcinomas and immunohistochemical TTF-1 positivity may be used as a marker of malignancies metastasized from lung and thyroid. Although they are used extensively in daily pathological practice, detailed study of this antibody in some of neoplasms that may show difficulties in differential diagnosis is lacking. In this study, we aimed to determine the usefulness of TTF-1 positivity in the differential diagnosis of gastric carcinomas from lung malignancies.

Materials and methods: We examined TTF-1 expression in primary adenocarcinoma and non-cohesive carcinoma of the stomach. Surgical resection materials from 132 patients with gastric carcinoma were evaluated. The diagnosis of primary site was identified for all cases by clinical, radiological and/or histological correlation and the possibility of metastatic carcinoma was excluded. Immunohistochemical analysis was performed on the tissue-microarray block sections.

Results. Among 123 gastric carcinomas, 4 (3.25%) cases showed strong nuclear positivity with TTF-1. None of the 9 poorly cohesive gastric carcinomas stained for TTF-1.

Conclusions: In summary, our results show that TTF-1 positivity may be observed especially in gastric adenocarcinoma.