Aims: Amplification of c-erbB-2 proto-oncogene has been reported in endocrine tumours, but the results were unclear and no predictive prognostic value has been established in the case of phaeochromocytoma. We investigated the immunohistochemical expression of c-erbB-2 oncogene in 34 cases of human phaeochromocytoma (27 sporadic, seven familial type MEN (multiple endocrine neoplasm)) in order to find out if it could be used to differentiate sporadic and familial forms and whether c-erbB-2 expression is related to tumour biological behaviour.
Methods and results: All the cases showed diffuse, generally heterogeneous, intracytoplasmic granular c-erbB-2 staining. The percentage of tumour cells expressing c-erbB-2 was used as the comparative variable. The percentage of c-erbB-2 positive cells had a statistically significant (P < 0.001) relationship with tumour aggressiveness, as manifested by the presence of distant metastasis or association with other malignant neoplasms. We also found significantly higher levels (P = 0.007) of c-erbB-2 overexpression in MEN phaeochromocytoma than in sporadic cases.
Conclusions: These results clarify the important role of c-erbB-2 proto-oncogene in the pathogenesis of human phaeochromocytoma and confirm the unfavourable prognostic significance of c-erbB-2 expression.