Upregulation of SCC-S2 in immune cells and tumor tissues of papillary thyroid carcinoma.

Studies have shown that SCC-S2 can be detected in cancer cells, but its relation with thyroid cancer remains uncertain. In the current study, we investigated SCC-S2 expression in thyroid cancer from the immune cell perspective and tumor tissue perspective. Levels of SCC-S2 in CD4+ T cells, CD8+ T cells, monocytes, natural killer (NK) T cells, tumor tissues, and adjacent noncancerous thyroid tissues were tested by real-time reverse transcription PCR and Western blot. Results revealed that mRNA and protein levels of SCC-S2 were significantly increased in peripheral CD4+ (mRNA, 1.90-fold; protein, 1.55-fold) and CD8+ T cells (mRNA, 2.37-fold; protein, 1.72-fold) but not monocytes and NKT cells in patients than in healthy donors. Further elevated mRNA level but not protein expression was observed in tumor-infiltrating CD4+ T cells, whereas both mRNA level and protein expression were further increased in tumor-infiltrating CD8+ T cells. Also, mRNA and protein levels of SCC-S2 in thyroid tissues were significantly elevated than those in adjacent noncancerous thyroid tissues. Moreover, patients with cervical lymph node metastasis presented clearly higher mRNA and protein expression of SCC-S2 compared to those without cervical lymph node metastasis (p < 0.05). These results suggest that SCC-S2 may play roles in affecting both immune cells and tumor cells in the thyroid and may indicate a novel pathway for understanding the pathogenesis of the disease.