Significance of expression of suppressor of cytokine signaling proteins: Suppressor of cytokine signaling-1, suppressor of cytokine signaling-2, and suppressor of cytokine signaling-3 in papillary thyroid cancer.

Abstract

Uncontrolled cytokine signal transduction largely associated with oncogene activation, can have disastrous biological consequences. The suppressor of cytokine signaling (SOCS) proteins represent one of the mechanisms by which this rampant signaling can be dissipated. Thus, we aimed to study the expression of SOCS-1, SOCS-2, and SOCS-3 in patients having benign thyroid disease and papillary thyroid cancer. SOCS protein expression was studied in 45 patients with benign thyroid disease and in 83 papillary thyroid cancer patients by immunohistochemistry and their association with clinicopathological characteristics and overall survival in cancer patients were analyzed using SPSS software. Expressions of SOCS proteins were significantly higher in papillary thyroid cancer than in patients having benign disease. SOCS-1 expression was predominantly higher in males (P = 0.004), unilateral tumors (P = 0.030), and noninflammatory conditions (P = 0.028). SOCS-1 expression was also able to predict poor overall survival in subgroup of papillary thyroid cancer patients having larger tumor size (P = 0.013) and advanced stage disease (P = 0.033). Expression of SOCS-2 significantly correlated with tumor size (P = 0.017), extrathyroidal extension (P = 0.000), residual disease (P = 0.043), and treatment (P = 0.007), while preponderance of SOCS-3 expression was observed in males (P = 0.030) and in patients having extrathyroidal extension (P = 0.011) and absence of metastasis (P = 0.032). Expression of the studied SOCS proteins may be a consequence of activation of Janus kinase-signal transducers and activators of transcription and other pathways supporting growth and survival of cancer cells that are sustained by several cytokines. Thus, SOCS-1, SOCS-2, and SOCS-3 proteins may directly or indirectly, have important roles in development and pathogenesis of papillary thyroid cancer.