Research Of CpG Island Methylation Status Of NIS And RASSF1A Gene Promoter In Papillary Thyroid Carcinomas

Objective: To understand the molecular changes and gene inactivation mechanism in Papillary Thyroid carcinomas(PTC),The methylation status of the promoter region of functional gene NIS and anti-oncogene RASSF1A in PTC and adjacent thyroid tissures were detected by Methylation-Specific PCR(MSP) and the relationship of methylation status and clinical characteristic was analyzed. Methods: The thyroid genomic DNA of tumor tissues and adjacent tissues was purified by standard methods from 34 patients with Papillary Thyroid carcinomas(PTC), the methylation status was detected by methylation-specific PCR technique (MSP) and the results was analyzed by SAS9.13 softwear. Results:(1)The methylation status of the promoter region of functional gene NIS:①30 cases in 34 of PTC tissues were detected hypermethylation and 23 cases in 34 were detected in adjacent thyroid tissues, the rate of methylation of NIS promoter in PTC carcinoma was significantly higher than that of adjacent thyroid tissues (P<0.05 ).②The rate of methylation in PTC patients with lymph nodes metastasis (18/18) was obviously higher than that without lymph nodes metastasis(12/16) (P<0.05).③No significant difference methylation rates was found only the II-III and stage I (P>0.05) .(2) The methylation status of the promoter region of anti-oncogene RASSF1A:①The methylation rates of RASSF1A gene in PTC tissues was 55.9%(19/34), while the methylation rates of RASSF1A gene in adjacent thyroid tissues was 23.5%(8/34), the rate of methylation of RASSF1A promoter in PTC carcinoma was significantly higher than that of adjacent thyroid tissues (P<0.05).②The rate of methylation in PTC patients with lymph nodes metastasis was 77.8% (14/18) , obviously higher than that without lymph nodes metastasis 31.3% (5/16) (P<0.05).；③The methylation rates of RASSF1A gene in PTC of stage II-III was 88.8% (8/9), significantly higher than that in PTC of stage I 44.0%(11/25) . (3)The relationship of methylation status of the promoter region of functional gene NIS and anti-oncogene RASSF1A in PTC:①The methylation rates of NIS gene was significantly higher than that of anti-oncogene RASSF1A in PTC(P<0.05 )②The relationship of methylation status of the promoter region of functional gene NIS and anti-oncogene RASSF1A in PTC is positive correlation(r_s,=0.41, P=0.0158<0.05) Conclusion: Methylation of NIS and RASSF1A Gene in promoter region is a common molecule event in human PTC , those two gene methylation cue some positive correlation and may play some role in the development and progression of PTC.