Study Of Clinical-pathological Characteristics And Related Gene Mutations In Head & Neck Paragangliomas

Objective:To analyze the clinical and biological characteristics of HNPGL in Chinese people. To probe the relationship of SDH, HIF-1 and VEGF with the occurrence and progression of HNPGL. To find out the prevalence of SDHB, SDHC and SDHD mutations in patients with PGL and to figure out whether there is any difference with respect to the data that published.Methods:1) 132 sporadic PGLs who were diagnosed at TMUCH from 1956.4 to 2010.10 with complete clinical and pathological data were investigated. We analyzed these patients exclusively with gender, age, tumor characteristics, pathological analysis, local invasion, Shamblin classification and compared the time trend of partial epidemic parameters.2) Peripheral venous bloods were draw from all the patients and genomic DNA was extracted with TKM method, organization genomic DNA was extracted by Blood/cell/organization genomic DNA extracted kit. Each amplification fragment of SDH exons gained through PCR were sequenced directly after purification. The results of sequencing are compared with standard sequence published in NCBI using the software of BLAST.3) We picked up 48 cases which were provided with complete clinical and pathological dates to detect the expression of SDH, HIF-1 a and VEGF in tumor tissue using immunohistochemical method.Results:1) Clinical data:the sex ratio of men to women is 1:1.55 (48/74), including:81 cases of carotid body tumor,16 cases of glomus jugulare tumor,12 cases of vagal paraganglioma,6 cases of tympanum tumor; According to the Shamblin classification: 20 case were sorted as Shamblin I,43 cases as Shamblin II and 18 cases as Shamblin III. The sex ratio of benign and malignant tumor is 1:1.2 and 1:0.8 respectively. The average diameter and onset age of benign tumor is 5.5cm and 40.5 years, as malignant tumor is 6.6cm and 43.1 years. Only 1 patients afflicted with bilateral lesions in 22 malignant HNPGL patients without family history temporally; 3 cases have pedigrees phenomenon and 21 cases have lateral lesions among these benign tumors. The statistical analysis results according to number of patients, median age and sex ratio divided by period shows that numbers of patients and female patients increased by year, however, median age decreased by year.2) Gene mutation detection:We extracted full germline DNA from 42 among 132 cases, among of 11 cases were detected with SDH gene mutation and 3 cases carried a nonsense mutation in SDHD-exon 2 located at the 112th bp, C>T; 2 cases carried a missense mutation in SDHD-exon 3 located at the 311th bps, A>C; 4 cases carried a synonymous mutation in SDHB-exon 1 located at the 18th bp,C>A; 2 cases carried a missense mutation in SDHB-exon 6 located at the 594th bp,C>A; We detected a mutation in the exon 2 of SDHD, so does his uncle. His father and son were carriers, and his sister didn’t present any mutation with control, we didn’t find any mutation in the exon of SDHC and SDHAF2.3) IHC:the positive ratio of 48 HNPGL cases in SDHB is 64.6%, in SDHC is 91.7%, in SDHD is 87.5%, in HIF-la is 85.7% and in VEGF is 100%. SDHB is related with HIF-la; the expression of HIF-la and VEGF is positively related with Shamblin classification; the expression of HIF-la is positively related with VEGF; the expression of HIF-1a and VEDF in carcinoma is higher than in normal tissue.Conclusions:1) In this study, benign HNPGL was more common in women, while malignant HNPGL was more common in man; the onset age of benign HNPGL was older than malignant one, and the tumor diameter of benign HNPGL was smaller than malignant one; benign HNPGLs were more likely to be bilateral lesions and pedigrees were main with benign lesions.2) In the view of time axis, HNPGL were tend to be onset at a younger age and the proportion of female patients is on the rise.3) In China, HNPGLs were tend to carry mutation in SDHB and SDHD, while rarely carry mutation in SDHC and SDHAF2.4) The mutation of SDHD was related with benign, mutifocal and familial HNPGL, which indicated that this mutation may be one of the molecular basis of the incidence of familial paraganglioma of the incidence.5) The mutation of SDHB had some relation with malignant HNPGL, the synonymous mutation of the 1st exon of SDHB (A6A) may be one of the reasons that affect the phenotype of paraganglioma.6) This topic in Chinese patients with sporadic HNPGL discovered a new mutation-missense mutation in 3rd exon of SDHD,322A>C and the 104th codon was changed from CAC to CCC, namely the histidine into proline (H104P). This mutation may be related to the invasive character of tumor.7) The mutation of SDH and the high expression of HIF-la, VEGF in HNPGL indicated that the abnormal of oxygen conduction pathway, tissue hypoxia and angiogenesis has some relation with the onset or progression of HNPGL.8) The positive expression of HIF-1a and VEGF may contribute to differentiate the tumor from benign and malignant.9) HIF-la and VEGF may play a promoting role in the development process of HNPGL invasion.