[Expression of SDHB, EPAS1 and MIB-1 in Zuckerkandl paragangliomas]

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.

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 (+).

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).

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.