Epitopes specificity of antibodies to thyroid peroxidase in patients with Graves' disease, Hashimoto's thyroiditis and overlap-syndrome.

Background: Antibodies against thyroid peroxidase (anti-TPO) serve as clinical markers of thyroid autoimmune diseases (TAIDs). By trying to elucidate the causes of heterogeneity in autoantibody levels among patients with different TAIDs it becomes possible to clarify the pathophysiology of GD and HT. Objective: To investigate the heterogeneity of epitopes recognized by anti-TPO in patients with Hashimoto's thyroiditis (HT), Graves' disease (GD) and overlap-syndrome. Methods: We carried out a cross-sectional study on 398 patients with GD, HT and overlap syndrome and analyzed the specificity of epitopes and binding constants of TPO with monoclonal antibodies (MAbs). Ten MAbs to TPO were used, of which five were reactive with native TPO and the rest were reactive with denaturated TPO. Results: The autoantibodies in blood serum of HT patients inhibited the binding of MAb63 more significantly than those in serum of GD patients: 59.62 % versus 54.02 %, respectively (p = 0.001). The anti-TPOs in serum of GD patients inhibited the binding of MAb77 more significantly than those in serum of HT patients: 54.36 % versus 51.13 %, respectively (p = 0.047). The binding of MAb45 was more inhibited in serum of patients with anti-TPO concentration over 1000 IU/ml (58.36 %). The blood serum of patients with overlap-syndrome showed less significant inhibition of MAb63 binding than that of patients with no overlap-syndrome: 52.47 % versus 58.81 %, respectively (p = 0.043). Conclusion: Mapping the epitopes to TPO with the help of MAbs may improve the differential diagnosis between different thyroid autoimmunities.

Analysis of the association of BRAFV600E mutation and Ki-67 overexpression with clinical and pathological characteristics in papillary thyroid cancer.

In recent years, many studies were dedicated to the search for genetic markers in thyroid malignancies, including papillary thyroid cancer. This study was designed to investigate the prevalence of BRAFV600E mutation in the PTC in the Kazakh population, to evaluate the relationship between BRAF V600E mutation status and the clinicopathological features of PTC. Besides, we aimed at assessing of the relationship between the high proliferation index and the clinicopathological features of PTC and also between the concomitant coexistence of BRAFV600E and the high proliferative index with clinicopathological features of PTC. We carried out a cross-sectional study on 123 patients with PTC of Kazakh ethnicity and analyzed their clinical, laboratory, and genetic findings. The study groups were pooled based on the presence of mutated or wild-type BRAFV600E and quantitative assessment of Ki-67 marker expression. In the course of our study, we found that the age of patients from the group of BRAF gene mutation was significantly higher than that of patients from the wild-type group (48.63 ± 14.07 years versus 40.23 ± 14.34 years) (t = - 3.257; p = 0.001). Correlation analysis between BRAF mutation, Ki-67 expression, their combination and various clinical and pathological parameters in PTC patients showed that older age was positively correlated with higher frequency of mutant BRAF gene (r = 0.284; p < 0.001), while more advanced stage of tumor was positively correlated with higher expression of Ki-67 (r = 0.307; p < 0.001). To understand the significance of detecting the BRAFV600E mutation and an increased level of Ki-67 expression in the choice of patient therapy tactics, larger studies are required with patient survival as one of the primary outcomes.

The Contribution of Genetic Variants to the Risk of Papillary Thyroid Carcinoma in the Kazakh Population: Study of Common Single Nucleotide Polymorphisms and Their Clinicopathological Correlations.

Objective: Risk for developing papillary thyroid carcinoma (PTC), the most common endocrine malignancy, is thought to be mediated by lifestyle, environmental exposures and genetic factors. Recent progress in the genome-wide association studies of thyroid cancer leads to the identification of several genetic variants conferring risk to this malignancy across different ethnicities. We set out to elucidate the impact of selected single nucleotide polymorphisms (SNPs) on PTC risk and to evaluate clinicopathological correlations of these genetic variants in the Kazakh population for the first time. Methods: Eight SNPs were genotyped in 485 patients with PTC and 1,008 healthy control Kazakh subjects. The association analysis and multivariable modeling of PTC risk by the genetic factors, supplemented with rigorous statistical validation, were performed. Result: Five of the eight SNPs: rs965513 (FOXE1/PTCSC2, P = 1.3E-16), rs1867277 (FOXE1 5'UTR, P = 7.5E-06), rs2439302 (NRG1 intron 1, P = 4.0E-05), rs944289 (PTCSC3/NKX2-1, P = 4.5E-06) and rs10136427 (BATF upstream, P = 9.8E-03) were significantly associated with PTC. rs966423 (DIRC3, P = 0.07) showed a suggestive association. rs7267944 (DHX35) was associated with PTC risk in males (P = 0.02), rs1867277 (FOXE1) conferred the higher risk in subjects older than 55 years (P = 7.0E-05), and rs6983267 (POU5F1B/CCAT2) was associated with pT3-T4 tumors (P = 0.01). The contribution of genetic component (unidirectional independent effects of rs965513, rs944289, rs2439302 and rs10136427 adjusted for age and sex) to PTC risk in the analyzed series was estimated to be 30-40%. Conclusion: Genetic factors analyzed in the present work display significant association signals with PTC either on the whole group analysis or in particular clinicopathological groups and account for about one-third of the risk for PTC in the Kazakh population.

Clinical implications of pre-operative rapid BRAF analysis for papillary thyroid cancer.

The activating point mutation of the BRAF gene, BRAF(T1799A), is the most common and specific genetic alteration in adult papillary thyroid carcinoma (PTC) and a possible marker of malignant potential of PTC. We have applied the PCR-RFLP method using fine-needle aspiration biopsy samples not only to our clinical practice but also to the international medical assistance effort around the Semipalatinsk Nuclear Testing Site in Kazakhstan. Seventy-seven cases (100 nodules) from Japan and 131 cases (137 nodules) from Kazakhstan were examined. There were 14 Japanese and 76 Kazakhstani cases of cytological malignant tumors from the examined samples. We detected 12 (85.7% of PTC) and 19 (25% of PTC) cases with BRAF(T1799A) among the Japanese and Kazakhstani cases, respectively. Of these cases, we found mutations in one cytologically "suspicious" case and even in two pathologically "benign" cases (after surgery in Kazakhstan). All of the BRAF mutation-positive cases, including those three, were confirmed as PTC by careful pathological examination, including immunohistochemical analysis. In summary, our PCR-RFLP method for BRAF(T1799A) detection using FNAB samples is useful not only for preoperative diagnosis of PTC but also as a complementary diagnostic tool for accurate pathological diagnosis, even after surgery.

Iodine prophylaxis around the Semipalatinsk Nuclear Testing Site, Republic of Kazakstan.

OBJECTIVE: This study aimed to clarify the iodine deficiency status in the Semipalatinsk region that has been contaminated by radioactive fallout from nuclear testing during the period of the former USSR. DESIGN: Based on the Japan-Kazakstan joint project of adult cancer screening around the Semipalatinsk Nuclear Testing Site (SNTS), from May to October 2002 spot urine specimens were collected at random in each village. Separately, children aged 5-15 years from around the SNTS were chosen at random and spot urine specimens were collected from them. SETTING: Area contaminated by radioactive fallout around the SNTS, Republic of Kazakstan. SUBJECTS: A total of 2609 adults aged >40 years from 16 settlements in three regions and one city, and 298 children aged 5-15 years from two regions and one city. RESULTS: Median urinary iodine concentrations of adults and children in all regions were in the range of 116.0-381.7 and 127.7-183.0 microg l(-1), respectively. The highest prevalence of values <50 microg l(-1) (14.1%) did not exceed 20%. Distributions within each group, adults and children, showed almost the same pattern, except for one region where more than 50% of adults had urinary iodine concentration >100 microg l(-1). CONCLUSIONS: In agreement with our previous studies, the urinary iodine concentration data showed no clear evidence of iodine deficiency around the SNTS. Kazakstan is geographically and nutritionally at moderate risk of iodine deficiency disorders without fortification or iodine replacement by iodised salt. The socio-medical prophylaxis against iodine deficiency has been successfully maintained in East Kazakstan.