Endocrine Abstracts

Aim: The aim 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.

Materials and Methods: This study was carried out retrospectively. 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 or nodular goitre. 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.

Results: GLP-1R expression was positive in 17.5% of the controls, 15.0% of the FTCs, and 5.0% of the MTCs, 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, 5.0% of the FTCs and 10.0% of the MTCs; 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. Leptin scores were statistically significantly higher in FTC group than in the control, MTC and PTC-fv groups (P=0.037, P=0.014, P=0.014). Leptin score was significantly higher in the presence of vascular invasion (P=0.002).

Conclusion: 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 detect negative expression of IGF-1R. 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.

Keywords: Thyroid cancer, Leptin, IGF-1, GLP-1