EXPRESSIONS OF TGF-β1 AND TIMP-2 IN THYROID CARCINOMA TISSUES AND THEIR CORRELATIONS WITH TUMOR INVASION AND METASTASIS

Xing Li1, RongXia Li2, Jing Tian3*

1Department A of Thyroid and Breast Surgery, The Affiliated Hospital of Inner Mongolia Medical University, No. 1 Tongdao North Street, Huimin District, Hohhot, Inner Mongolia, 010050 - 2Drug Clinical Trial Institute, The Affiliated Hospital of Inner Mongolia Medical University - 3Department of Intensive Medicine, The Affiliated Hospital of Inner Mongolia Medical University

Purpose: To investigate the level of expressions of transforming growth factor β1 (TGF-β1) and tissue inhibitor of metallopro- teinase-2 (TIMP-2) in thyroid carcinoma (TC) tissues and their correlations with tumor invasion and metastasis.

Methods: Cancerous tissues and adjacent normal tissues of 136 patients with TC were randomly assigned to two groups: TC group and control group. The patients consisted of 46 males and 90 females aged 11 to 85 years (mean age = 48.0 ± 37.0 years), and were recruited over a 5-year period for this study. There were 66 cases of thyroid papillary carcinoma (TPC), 30 cases of thyroid fol- licular carcinoma (TFC), 31 cases of medullary thyroid carcinoma (MTC) and 9 cases of undifferentiated thyroid carcinoma (UTC). Biopsy samples were taken from the patients using biopsy needle, and the levels of expressions of TGF-β1 and TIMP-2 were determined with immunohistochemical staining. Correlations of levels of expressions with tumor invasion and metastasis were also evaluated.

Results: The positive expressions of TGF-β1 and TIMP-2 were significantly higher in TC group than in control group (p<0.05). The levels of expressions of TGF-β1 and TIMP-2 were significantly higher in the TPC group than in TFC, MTC and UTC groups (p<0.05). The expression levels of TGF-β1 followed the order: TPC > TFC > MTC > UTC, while the levels of expressions of TIMP-2 followed the order: TPC > MTC > TFC > UTC. There were no significant differences in the expressions of TGF-β1 in TC patients of different ages, sex, and lymph node metastasis (p>0.05). The expressions of TGF-β1 were significantly higher in female patients, those with tumor size > 1.0 cm, and patients with tumor invasion than in male patients, patients with tumor size < 1.0 cm, and patients without tumor invasion (p<0.05). There were no significant differences in the levels of expressions of TIMP-2 in TC patients with lymph node metastasis (p>0.05). The expressions of TIMP-2 were significantly higher in TC patients aged > 48 years, females, patients with tumor size > 1.0 cm and those with tumor invasion, than in patients aged < 48 years, males, patients with tumor size < 1.0 cm and those without tumor invasion. There was a positive correlation between the expressions of TGF-β1 and TIMP-2 in patients with TC.

Conclusion: The results obtained in this study have shown that TGF-β1 and TIMP-2 are highly expressed in TC tissues. While the expression of TGF-β1 is not related to the different histological types, the expression of TIMP-2 is related to the histological types. The level of expression of TGF-β1 in TC tissues is positively correlated with tumor size, tumor invasion and lymph node metastasis, while TIMP-2 expression is positively correlated with tumor invasion and lymph node metastasis.