Predictive value of sphingosine kinase 1 expression in papillary thyroid carcinoma

Abstract

Background/Aim: Sphingolipid metabolites are emerging as key signaling molecules in cancer. Sphingosine kinase 1 is up-regulated in many different types of human malignancies and plays a crucial role in cancer development and progression. The utility of sphingosine kinase 1 to act as a predictive biomarker in thyroid cancer remains unclear. Materials and Methods: Sphingosine kinase 1 expression was evaluated using immunohistochemical staining in 110 formalin-fixed, paraffin-embedded papillary thyroid carcinoma tissue samples. Results: Sphingosine kinase 1 expression in papillary thyroid carcinoma tissue was significantly higher than in nodular goiter (p<0.001) or normal thyroid (p<0.001) tissue. Sphingosine kinase 1 was observed in the cytoplasm of tumor cells. Thirty-four (30.9%) of 110 papillary thyroid carcinomas exhibited high sphingosine kinase 1 expression, that was significantly associated with tumor multiplicity (p=0.004), extrathyroidal extension (p=0.013), presence of lymph node metastasis (p<0.001), and number of metastatic lymph nodes (p=0.042). In addition, high sphingosine kinase 1 expression was the only independent predictor of lymph node metastasis (p<0.001). Conclusion: Sphingosine kinase 1 is involved in papillary thyroid carcinoma development and progression and can serve as a potential biomarker predictive of lymph node metastasis.