Tiroid kanserinin obezite ile ilişkisi ve GLP-1, IGF-1 ve leptin'in rolü

FATMA BAŞIBÜYÜK ŞAHİN

Tiroid kanserinin obezite ile ilişkisi ve GLP-1, IGF-1 ve leptin'in rolü

Thesis Type: Expertise In Medicine

Institution Of The Thesis: Ankara University, Tıp Fakültesi, Dahili Tıp Bilimleri Bölümü, Turkey

Approval Date: 2017

Thesis Language: Turkish

Student: FATMA BAŞIBÜYÜK ŞAHİN

Supervisor: MUSTAFA ŞAHİN

Open Archive Collection: AVESIS Open Access Collection

Abstract:

Aim: The aim of this study was to assess the expressions of GLP-1, IGF-1 and leptin in the paraffin sections of operated thyroid cancer and non-thyroid cancer patients, and show the relationship of GLP-1, IGF-1 and leptin receptor expressions with thyroid cancer, comparatively. Assessment of the association of thyroid cancer with obesity and diabetes was also aimed. Materials and Methods: This study was carried out retrospectively in Departments of Endocrinology and Metabolism and Pathology of Ankara University Faculty of Medicine between 01/04/2016 - 01/04/2017. A total of 120 patients were included in the study. The case groups consisted of 20 medullary thyroid cancer (MTC), 20 follicular thyroid cancer (FTC), 20 classical papillary thyroid cancer (PTC-kl) and 20 follicular variant papillary thyroid cancer (PTC-fv). The control group consisted of 40 patients with Hashimoto thyroiditis (HT) or nodular goitre (NG). Socio-demographic characteristics, disease and drug use status, resume and family history characteristics and laboratory values were obtained from the patient's file information. The IGF-1 receptor (IGF-1R), GLP-1 receptor (GLP-1R), and leptin receptor (leptin-R) expressions were examined by immunohistochemical staining using thyroid gland paraffin blocks in Pathology Department. Evaluation of IGF-1R and GLP-1R expressions was only made as staining present or absent. A scoring system was used for leptin-R expression. Results:Gender and age averages were similar between the participant groups (p = 0.069, p: 0.412). There was no significant difference in body mass index (BMI) between the control group and the cancer groups in the pairwise comparisons. GLP-1R expression was positive in 17.5% of the controls (7), 15.0% of the FTCs (3), and 5.0% of the MTCs (1), whereas no GLP-1R expression was detected in any of PTC-kl and PTC-fv. The difference between the groups was not statistically significant (p = 0.064). In addition, in 9 cancer cases (5 MTC, 4 PTC-KL), 5% GLP-1R expression was detected in normal tissues. While IGF-1R expression was positive in 7.5% of the controls (3), 5.0% of the FTCs (1) and 10.0% of the MTCs (2); IGF-1R expression was not detected in any one of the PTC-kl and PTC-fv. This difference between the groups was not statistically significant (p = 0,618). The mean leptin score was 1.75 ± 1.81 (median: 2) in the control group, 3.0 ± 2.62 (median 4) in FTC, 1.15 ± 1.87 (median 0) in MTC, 1,80 ± 2,12 (median 0) in PTC-kl, and 1.05 ± 1.79 (median 0) in PTC-fv. In pairwise comparisons of groups in terms of leptin scoring, Leptin scores were statistically significantly higher in FTC group than in the control, MTC and PTC-fv groups (p = 0.037, p = 0.014, and p = 0.014, respectively). Leptin score was significantly higher in the presence of vascular invasion (p = 0.002). Conclusion: Contrary to previous studies, there was no significant relationship between thyroid cancer and obesity in our study. GLP-1R staining was not statistically significant in the FTC, MTC, and PTC groups compared to the control group. However, the presence of GLP-1R positivity in the control group and the detection of GLP1-R expression in surrounding normal tissues in the presence of cancer suggests that GLP1 may play a role in tumorigenesis and loss of receptor expression after tumor development. Contrary to previous studies, our study is the first study to detect negative expression of IGF-1R. In addition, the relationship between IGF-1 and thyroid cancer is not clear in many studies. In our study, Leptin-R expression was found to be significantly higher in the FTC than in the control group. It was also found that high levels of leptin expression were associated with vascular invasion. It is thought that leptin may be associated with FTC formation and poor prognosis. The retrospective nature of our study, inability to access to some cases' files, and the fact that the control group consists of only thyroid patients are limiting factors. New prospective studies are needed.