SDHB and CDK1 protein expression in metastatic pheochromocytoma and paraganglioma

Background Pheochromocytomas and paragangliomas (PPGL) are rare and mostly non-metastatic tumors from adrenal medulla and paraganglia. Metastatic PGL 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 if SDHB and CDK1 expression is associated with metastatic capacity in PPGL. Material and Methods A tissue micro array (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 was 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 towards 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.