SDHB and CDK1 protein expression in metastatic pheochromocytoma and paraganglioma.

BACKGROUND: Pheochromocytomas and paragangliomas (PPGLs) are rare and mostly non-metastatic tumors originating from adrenal medulla and paraganglia. Metastatic PGLs have a worse prognosis, but currently, there are no established criteria to determine PPGL metastatic potential. AIM: The aim of this study was to investigate whether SDHB and CDK1 expression is associated with metastatic capacity in PPGL. MATERIAL AND METHODS: A tissue microarray (TMA) was constructed from 175 tumors from a total of 149 unique PPGL patients treated at Sahlgrenska University Hospital. SDHB, CDK1, and proliferation index Ki-67 were assessed and correlated to metastatic capacity defined as a confirmed metastatic event. RESULTS: Negative SDHB expression was more common in patients with metastatic PPGL and displayed a trend toward lower overall survival and correlation with higher Ki-67%. High CDK1 expression was not associated with any of the parameters mentioned above. CONCLUSION: Negative SDHB expression but not high CDK1 expression is associated with metastatic capacity in PPGL.