Thyroid transcription factor (TTF-1) is initially identified as a mediator of thyroid-specific gene transcription and transcription of surfactant proteins in lung. Its expression was characteristically seen in the nuclei of lung and thyroid epithelia and their tumors. Cytoplasmic staining with TTF-1 was noted in normal and neoplastic tissue samples including normal hepatocytes and hepatocellular carcinoma (HCC). This study was conducted on 36 archival hepatic specimens, grouped as follows: 36 sections from peri-malignant benign hepatic tissue (chronic hepatitis C); 33 sections from tumor tissue of HCC and 15 sections from foci of liver cell dysplasia. TTF-1 expression was detected in all dysplastic and HCC lesions and in 75% of perimalignant lesions. Marked intensity staining predominates in HCC lesions with more expression in higher grades of HCC, while moderate intensity predominates in dysplastic and perimalignant lesions. HCC lesions showed mainly diffuse staining pattern which is more pronounced in higher grades of HCC, while patchy staining appeared mainly in dysplastic and perimalignant lesions. TTF-1 expression in perimalignant tissue showed marked intensity in higher grades of necroinflammation and in cirrhotic lesions. Patchy staining predominates in higher grades of necroinflammation and in fibrotic lesions, while nodular staining expressed only in cirrhotic nodules. Mean percentage of positive hepatocytes increases significantly in HCC lesions compared to dysplastic and perimalignant lesions. TTF-1 showed lower expression in perimalignant tissue, higher expression in dysplastic lesions and sustained increased expression in hepatocellular carcinoma. So changes in hepatocellular expression of TTF-1 are upregulated in cases of hepatitis C and in HCV induced HCC.
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