琥珀酸脱氢酶B和核增殖指数MIB-1在嗜铬细胞瘤／副神经节瘤中表达的意义

Study on the overexpression of succinate dehydrogenase B and MIB-1 in pheochromocytoma/ paraganglioma tissue

目的 探讨嗜铬细胞瘤/副神经节瘤（PHEO/PGL）中琥珀酸脱氢酶（SDH）B突变和核增殖指数MIB-1表达情况，以及二者作为预测恶性嗜铬细胞瘤指标的意义。方法 回顾性分析2008年8月至2016年4月收治的93例PHEO/PGL患者的临床资料，男57例，女36例。年龄34岁（8-73）岁。有高血压病史者79例，查体发现肾上腺肿瘤14例。PHEO 68例，PGL 25例。有典型高儿茶酚胺分泌症状者66例，功能静止性PHEO/PGL 27例。良性PHEO/PGL 77例，恶性PHEO/PGL 16例。肿瘤位于左侧39例，右侧32例，多发22例。肿瘤直径（6.8 ±2.7）cm。术前24 h尿儿茶酚胺测定：肾上腺素（42.6±5.1）μg/24 h，去甲肾上腺素（167.5±13.5）μg/24 h，多巴胺（246.4±71.2）μg/24 h。选取6例泌尿系统非肿瘤、非遗传性疾病患者作为对照组。所有患者留取外周血分别行SDHB、SDHAF2、SDHC、SDHD、VHL及RET基因突变检测。采用免疫组化染色法检测93例PHEO/PGL组织标本中SDHB、MIB-1、EPAS1、血管内皮生长因子-1受体（VEGF-1R）和嗜铬粒蛋白A（CgA）的表达情况。阳性颗粒状细胞质染色〉50%为强阳性（＋＋＋），11%-50%为中度阳性（＋＋），1%-10%为弱阳性（＋），〈1%为阴性（－）。结果 93例PHEO/PGL患者中，SDHB、SDHAF2、SDHC、SDHD、VHL及RET基因突变27例（29.5%），其中SDHB基因突变9例，RET原癌基因突变8例，VHL基因突变3例。免疫组化染色检测示，9例SDHB基因突变者组织标本中MIB-1阳性表达7例。对照组行基因检测及MIB-1、EPAS1、CgA和VEGF-1R免疫组化染色检测均为阴性。EPAS1在PHEO/PGL中为中度阳性表达，在恶性PHEO/PGL中高表达。9例SDHB基因突变者中，7例EPAS1呈阳性染色，EPAS1阳性表达与CgA、MIB-1及VEGF-1R密切相关。结论 SDHB基因突变者常表现为PGL，9.8%的PGL与SDHB基因突变相关，其恶性危险性增加。SDHB突变者的组织标本中MIB-1表达增高，EPAS1、VEGF-1R阳性表达，与恶性PHEO/PGL侵袭和转移相关。

Objective We aimed to investigate the overexpression of succinic dehydrogenase （SDH）B and MIB-1 in patients with pheochromocytoma/paraganglioma（PHEO/PGLs） and its significance for predicting the clinical malignant behavior.Methods From August 2008 to April 2016, the clinical characteristics of 93 patients with PHEO/PGLs were analyzed retrospectively. There were 57 males and 36 females. with an average of 34 years, ranging 8-73 years old. There were 68 cases of adrenal pheochromocytoma and 25 cases of paraganglioma. There were 79 cases with hypertension and 14 cases of adrenal accidental tumors. Sixty-six cases with typical hyper-catecholamine secretion symptoms and 27 cases with non-functional PHEO/PGL. Benign PHEO/PGLs were 77 cases and malignant 16 cases. The tumor was located on the left side in 39 cases, on the right side in 32 cases and multiple lesions in 22 cases. The diameter of the PHEO/PGL tumor was （6.8±2.7） cm. The 24 h urine catecholamine was measured before operation, which showed epinephrine was（42.6±5.1）μg/24 h, norepinephrine was（167.5±13.5）μg/24h and dopamine was （246.4±71.2）μg/24h. Six cases wihtout hereditary diseases of urinary system were selected as normal control group. SDHB, SDHAF2, SDHC, SDHD, VHL and RET gene mutations were detected in all patients. Immunohistochemical panel has been performed to detect the expression of SDHB, MIB-1, EPAS1, VEGF-1 receptor （VEGF-1R）, and chromain A （CgA） in 93 specimens of PHEO/PGL tissue. The positive granular cytoplasm staining 〉50% was strongly positive （＋ ＋ ＋), 11% to 50% was moderately positive （＋ ＋), 1% to 10% was weak positive （＋) and the negative was compared with the known positive internal reference, that is, there was less than 1% or no stain completely.Results SDHB, SDHAF2, SDHC, SDHD, VHL and RET gene mutations in 27 cases （29.5%）. Nine patients with SDHB gene mutation （9.7%）. RET proto-oncogene mutations in 8 cases （8.6%）. 3 cases had VHL mutation （3.2%）. Immunohistochemical staining showed that MIB-1 positive expression was found in 7 of 9 patients with SDHB gene mutation. Six cases in the control group were negative for gene detection and MIB-1, EPAS1, CgA and VEGF-1R immunohistochemical results. EPAS1 showed moderately positive in patients with PHEO/PGL and strong positive in patients with malignant PHEO/PGL. In 9 cases with SDHM mutation, EPAS1 was noticed positive in seven cases, which showed the relationship with CgA, MIB-1 and VEGF-1R.Conclusions The SDHB gene mutation is usually shown as a paraganglioma focus outside the adrenal gland. And 9.8% of the paragangliomas were associated with a mutation of the SDHB gene with an increase in malignant risk. The SDHB mutation caused over-expression of MIB-1 and the positive expression of EPAS1 and VEGF-1R in PHEO/PGL tissues, which was associated with invasion and metastasis of malignant PHEO/PGL.