ABSTRACT
Objective To investigate the promoter methylation of drug metabolism genes CYP1A1 and CYP1B1 in thyroid cancer and its relationship with clinical pathological characteristics. Method 201 cases of thyroid cancer and 23 cases of normal thyroid tissues were involved. Methylation-specific PCR ( MSP ) was performed to analyze promoter methylation of CYP1A1 and CYP1B1 genes in the above tissues to detect the frequency of methylation positive, compare the promoter methylation level of CYP1A1 and CYP1B1 genes in papillary thyroid carcinomas ( PTC) and the controls. Five thyroid cancer cell lines were treated with methyltransferase inhibitor 5-Aza-dC for 5 days, and real time PCR ( RT-PCR) was performed to evaluate the mRNA expression of CYP1A1 and CYP1B1 genes. Logistic regression was used to analyze the correlation between the aberrant methylation and the clinical features. Results Aberrant methylation status in promoter region of CYP1A1 and CYP1B1 genes were detected in all kinds of thyroid cancers. Compared with control tissues, the methylation in promoter regions of CYP1A1 in PTCs was significantly higher, while that in promoter regions of CYP1B1 was lower (P<0.05). In vitro, 5-Aza-dC treatment significantly increased the CYP1A1 gene mRNA expression for 6. 92 and 8. 30 times in K1 and C643 cell lines respectively and restored CYP1B1 gene mRNA expression for 7.62 times in K1 cell line. Compared with the controls, PTCs with methylation in promoter regions of CYP1B1 had decreased lymphatic metastasis rate. Conclusion The methylation in promoter regions of CYP1A1 and CYP1B1 gene may regulate their mRNA expressions. Aberrant methylation of the promoter region of CYP1B1 is associated with lymph node metastasis in PTC.
ABSTRACT
Objective BRAFV600E mutation, RET/PTC rearrangement, and the concomitant of Hashimoto's thyroiditis(HT) could influence clinicopathological features of papillary thyroid carcinoma (PTC).This study is to investigate the distribution of three factors in PTC and to analyze their associations with clinicopathological characteristics.Methods Fine-needle aspiration samples were collected in a total of 122 conventional PTC patients, who were confirmed by surgery.The clinicopathological features were collected to analyze its association with different factors.BRAFV600E mutation and RET/PTC rearrangement were detected by pyrosequencing and Taqman-qPCR, respectively.Results BRAFV600E mutation was significantly correlated with an older age and a less coexistence with HT(P＜0.05).In contrast, RET/PTC rearrangement was more prevalent in young patients and was associated with the concomitant of HT(P＜0.05).In the age of ≥20 year and＜45 year groups, BRAFV600E mutation was significantly associated with extrathyroidal invasiveness.RET/PTC rearrangement was significantly associated with bilateral lymph node metastasis and the number of metastatic lymph node.Conclusions The distribution of three factors were different in PTC patients.In addition to the age at diagnosis, all of three factors should also be considered together to analyze the association of clinicopathological features of PTC.