The Expression Of Four Biomarkers In Thyroid Tumors And Their Significance

Objective:To study the expression of the four biomarkers arginaseⅡ(Arg2),chromosome-1 Open reading frame 24 (Clorf24), integral membrane proteinl (ITM1)and DNA damage-inducible transcript 3 (DDIT3) in thyroid tumors and im-prove the accuracy of diagnosis.Method:The first validation set was samples collected from the 39 patients under-going thyroid surgery for thyroid nodules between March 2010 and January 2011 in Nanjing general hospital of Nanjing military region,26 papillary thyroid carcino-ma(PTC) specimen and 13 follicular thyroid adenoma(FTA) specimen. These samples were frozen immediately after surgical biopsy and stored at-80℃. Final histologic classification was obtained from paraffin-embedded tissue. Total RNA was extracted from tissues according to the manufacturer's instructions, after reverse transcription, then a real-time fluorescence quantitative polymerase chain reaction(RT-PCR) assay of Arg2,ITIM1,Clorf24,DDIT3 and reference gene GAPDH was used to test mRNA expression level between the PTC group and FTA group. A second validation set was 81 paraffin-embedded sections,37 papillary thyroid carcinoma (PTC) specimen,20 follicular thyroid adenoma (FTA) specimen,20 follicular thyroid carcinoma (FTC) specimen and 4 medullary thyroid carcinoma. The expression of Arg2,ITIM1,Clorf-24,DDIT3 in these tissues was detected by immunohistochemical SP method.All data were analyzed by software SPSS 16.0.ΔCT values were analyzed by two-independent sample t test, Fisher exact test ofχ2 test was used to compare rates. P<0.05 was considered statistically significant.Result:1.Quantitative real-time PCR showed that the expression of Arg2 gene was significantly different between the PTC group and FTA group (P<0.05)The expression of Clorf24 gene in the PTC group differes significantly from that of the FTA group (P<0.01)The expression of DDIT3 gene and ITIM1gene showed no significant change be-tween DDIT3 and ITIM1 (P>0.05, P>0.05)2. With immunohistochemistry, the positive rates of Arg2 differs significantly be-tween benign and malignant thyroid tissues(p<0.05), and Arg2 could identify the fol-licular thyroid adenoma from papillary thyroid carcinoma, and the follicular thyroid adenoma from follicular thyroid carcinoma(p<0.05).The positive rates of Clorf24 differs significantly between benign and malignant thyroid tissues according to the type of immune response and different staining parts of cells (p<0.05), and Clorf24 could identify the follicular thyroid adenoma and pa-pillary thyroid carcinoma, the follicular thyroid adenoma and follicular thyroid carci-noma(p<0.05).The positive rates of ITIM1 and DDIT3 showed no significant differences in be-nign and malignant thyroid tumors(p>0.05).Conclusion:Arg-2 and Clorf24 could be considered as reliable markers in distin-guishing malignant from benign thyroid tumors. ITIM1 and DDIT3 could not be con-sidered as reliable biomarkers distinguishing benign and malignant thyroid tumors in protein and nuclear level.