Thyroid transcription factor-1 expression in invasive and non-invasive urothelial carcinomas.

BACKGROUND: Thyroid transcription factor-1 (TTF-1) has been considered a sensitive marker for thyroid and lung tumors. Recent data have shown that a wide range of neoplasms may express TTF-1. CASE SERIES: We performed an immunohistochemical study in a case series of 42 urothelial carcinomas (UCs) on tissue microarrays sections, in order to investigate how often UCs express the TTF-1 protein and the diagnostic utility of this marker. In addition, we sought to determine by immunohistochemistry if there is an association between TTF-1 expression and the expression of specific basal-like or luminal markers. Five out of the 42 cases (11.9 %) were positive for TTF-1. Three positive tumors concerned non-invasive papillary UCs. There was no association between TTF-1 expression and tumor grade (χ2, p =0.419), stage (χ2, p =0.550) or cytokeratin 5/6 (χ2, p =0.330), cytokeratin 20 (χ2, p =0.995) and estrogen receptors expression (χ2, p =0.268).
CONCLUSIONS: UCs may show TTF-1 expression and pathologists should be aware of this phenomenon in order to avoid misdiagnosis, notably in metastatic disease. HIPPOKRATIA 2017, 21(3): 154-157.