Evaluation of the type 1 insuline-like growth factor receptor (IGF-1R) expression by immunohistochemistry in malignant vs. benign pheochromocytomas/paragangliomas. Preliminary results.

PENNISI P; VENARA M; SANSO G; CHEMES, HE; BARONTINI, M

Mar del Plata, Argentina

Congreso; XIX Annual Meeting of the Sociedad Latinoamericana de Endocrinología Pediátrica (SLEP); 2007

SLEP

Pheochromocytomas and paragangliomas(feo/pgl) are rare neuroendocrine tumors derived from chromaffin cells. Although mostly benigns, up to 26% of feo/pgl will undergo malignant transformation.  The diagnosis of malignancy requires the presence of distant metastasis. Insulin-like growth factors have been shown to promote chromaffin cells survival and proliferation. In adrenocortical carcinomas, overexpression of IGF1-R has been observed. In contrast, expression of the IGF-1R appears to be similar to normal in adenocortical hyperplasia and adenomas. Aim: to characterize the distribution and expression of the IGF-1R in feo/pgl  of different origin and degree of malignancy, in order to establish a potential role for the IGFs in the pathogenesis of the disease. Methods: Benign (feo 5/pgl 1) and malignant (feo 2/pgl 3) tumors were processed for immunohistochemistry using a specific anti-IGF-1R antibody. Both,intensity and distribution of the labelling were evaluated (IDP: intense diffuse positive; CP: combined intense and weak positive areas; WDP weak diffuse positive). Results: IDP CP WDP Feo/pgl benign (n=6) 1 (16.6%) 3 (50%) 2 (33.3%) Feo/pgl malignant (n=5) 3 (60%) 2 (40%) 0 (0%) Conclusions: These results would indicate that both expression and distribution of the IGF-1R are different in malignat vs benign pheochromocitomas/paragangliomas, suggesting a potential role for the IGFs in the pathogenesis of the disease. Further studies are necessary to confirm these preliminary results.