Expression of hypoxia-inducible factor-1a (HIF-1a) in pituitary tumours

• S. Vidal ^[1] ; E. Horvath ^[2] ; K. Kovacs ^[2] ; T. Kuroki ^[3] ; R.V. Lloyd ^[4] ; B.W. Scheithauer ^[4]
  1. [1] Universidade de Santiago de Compostela

     Universidade de Santiago de Compostela

     Santiago de Compostela, España

     
  2. [2] University of Toronto

     University of Toronto

     Canadá

     
  3. [3] Toho University

     Toho University

     Japón

     
  4. [4] Mayo Clinic

     Mayo Clinic

     City of Rochester, Estados Unidos

     

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• Localización: Histology and histopathology: cellular and molecular biology, ISSN-e 1699-5848, ISSN 0213-3911, Vol. 18, Nº. 3, 2003, págs. 679-686
• Idioma: inglés
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• Resumen

  • The present study was performed to investigate HIF-1a (hypoxia-inducible factor-1a) expression in a large number of immunohistochemically and ultrastructurally characterized surgically removed pituitary tumours. The potential relation of HIF-1a with outcome variables as well as the presence of HIF-1a expression in the tumours treated with dopamine agonists and octreotide, a long-acting somatostatin analogue was also investigated. HIF-1a immunoreactivity was confined to the nucleoplasm whereas the nucleoli were unconspicuous. The distribution of HIF-1a was evident in the tumours whereas normal adenohypophysial cells showed no HIF- 1a staining. HIF-1a expression was detected not only in the tumour cells but also in endothelial cells lining the blood vessels within the tumour. ACTH producing adenomas showed the lowest level of HIF-1a expression whereas pituitary carcinomas and GH producing adenomas had the highest counts. The statistical study demonstrated no significant correlation between HIF-1a expression, patient age, gender, tumour, size, invasiveness, cell proliferation rate and vascularity. These results suggest that the behaviour of pituitary tumours does not primarily depend of HIF-1a expression. Our study demonstrated an increase HIF-1a expression in bromocriptine treated PRL producing pituitary adenomas compared with untreated tumours but no increase in octreotide treated tumours.