Phaeochromocytomas are uncommon tumours of adrenal or extra-adrenal chromaffin tissue. About 2–26% of these have been reported to metastasize, but, on histological criteria, it is virtually impossible to predict malignant behaviour of the tumour. Using immunohistochemistry, we analysed the protein expression of SNAIL, a zinc-finger transcription factor, in a series of 50 phaeochromocytoma specimens from 42 patients. We found that SNAIL-expressing cells are frequent in metastatic primary tumours and their metastases, whereas in tumours without metastases, SNAIL expression is commonly absent. We conclude that the expression of SNAIL may be of use in predicting the metastatic potential of phaeochromocytoma.
V Häyry, K Salmenkivi, J Arola, P Heikkilä, C Haglund and H Sariola
A Raitila, M Georgitsi, A Karhu, K Tuppurainen, M J Mäkinen, K Birkenkamp-Demtröder, K Salmenkivi, T F Ørntoft, J Arola, V Launonen, P Vahteristo and L A Aaltonen
Germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene were recently observed in patients with pituitary adenoma predisposition (PAP). Though AIP mutation-positive individuals with prolactin-, mixed growth hormone/prolactin-, and ACTH-producing pituitary adenomas as well as non-secreting pituitary adenomas have been reported, most mutation-positive patients have had growth hormone-producing adenomas diagnosed at relatively young age. Pituitary adenomas are also component tumors of some familial endocrine neoplasia syndromes such as multiple endocrine neoplasia type 1 (MEN1) and Carney complex (CNC). Genes underlying MEN1 and CNC are rarely mutated in sporadic pituitary adenomas, but more often in other lesions contributing to these two syndromes. Thus far, the occurrence of somatic AIP mutations has not been studied in endocrine tumors other than pituitary adenomas. Here, we have analyzed 32 pituitary adenomas and 79 other tumors of the endocrine system for somatic AIP mutations by direct sequencing. No somatic mutations were identified. However, two out of nine patients with prolactin-producing adenoma were shown to harbor a Finnish founder mutation (Q14X) with a complete loss of the wild-type allele in the tumors. These results are in agreement with previous studies in that prolactin-producing adenomas are component tumors in PAP. The data also support the previous finding that somatic AIP mutations are not common in pituitary adenomas and suggest that such mutations are rare in other endocrine tumors as well.