THE ASSOCIATION BETWEEN LYMPH NODE METASTASIS AND MOLECULAR MARKERS IN DIFFERENTIATED THYROID CANCER

There is no consensus regarding routine usage and benefits of molecular markers for prediction of prognosis and assessment of risk groups in differentiated thyroid cancer (DTC).

We aimed to investigate NIS, Galectin-3, PTEN, P53 and Ki67 expressions in tumor tissue and metastatic lymph nodes in PTC and their association with lymph node metastasis and prognosis.

Ninety two papillary thyroid cancer patients who underwent total thyroidectomy and central lymph node dissection were included in this study. NIS, Galectin-3, PTEN, P53 and Ki67 immunohistochemical stainings were performed for all surgical tumor tissues and metastatic lymph nodes of the 38 patients. Age, gender, tumor size, multifocality, capsular invasion, extrathyroidal extension and lymphocytic thyroiditis were assessed retrospectively.

Seventy three females (79.3%) and nineteen males (20.7%) were included in this study. Risk of lymph node metastasis was higher in tumors with capsular invasion and extrathyroidal extension (p=0.03 and p < 0.001). NIS, PTEN and Galectin-3 protein expressions in tumor tissue were not associated with gender, tumor size, multifocality, extrathyroidal extension, capsular invasion, lymph node metastasis and tumor recurrence. Mean Ki 67 proliferation index was 2.08±0.95%. Ki 67 proliferation index was associated with tumor size (p=0.012). Intensity and expression of NIS and PTEN in tumor tissue were concordant with intensity and expression in metastatic lymph nodes (p<0.001). Ki 67 proliferation index in tumor was concordant with metastatic lymph nodes (p=0.02).

NIS, PTEN, Galectin-3, Ki67 and P53 expressions were not associated with the risk of lymph node metastasis in PTC patients. Routine analysis of these markers does not seem to be favorable. Further studies with new markers are necessary to determine prognostic predictors.