Objective: To explore the significance of succinate dehydrogenase B (SDHB) mutation and EPAS1 overexpression in Zuckerkandl paragangliomas (PGL) and examine their correlations with malignant infiltration and metastasis.
Methods: From March 2008 to July 2011, the clinical profiles of 16 Zuckerkandl PGL patients were analyzed retrospectively. For increased diagnostic specificity, a complex immunohistochemical panel of tissue microarray was performed for SDHB, EPAS1 and MIB-1. Positive expression identified as a granular cytoplasmic staining. Greater than or equal to 50% as strongly positive (+++), 1% to 10% as weakly positive (+).
Results: Tissue microarray immunohistochemical staining showed SDHB immunoreactivity in the cytoplasm, whereas EPAS1 and MIB-1 in the nuclear of tumor cells. Positive expression of EPAS1 in which 13 cases of Zuckerkandl PGL. And high expression strongly associated with malignancy. SDHB mutation of 7 cases are all EPAS1 positive staining. Non-gene mutation 9 cases tumor specimens, 6 cases were EPAS1 positive expression (P < 0.05). CgA positive expression in 11 cases benign Zuckerkandl PGL, strongly positive in 4 malignant cases (4/4). MIB-1 below 1% in 12 cases of benign Zuckerkandl PGL. And in 4 malignant cases, MIB-1 was about 3%. Malignant neoplasms had significantly higher EPAS1, CgA and MIB-1 expression compared to benign counterparts (P < 0.05).
Conclusions: The SDHB mutation causes the EPAS1 over expression in PGL and correlation with higher positive expression of CgA and MIB-1. It may be one of the mechanisms of malignant invasiveness and metastasis in PGL.