SOX2 Is a Potential Novel Marker of Undifferentiated Thyroid Carcinomas.

Background Thyroid cancer is a very common endocrine malignancy. Cancer stem cells are attributable to initiation, progression, and treatment failure in thyroid carcinoma. In the current study, immunostaining of SRY-box 2 (SOX2) in thyroid carcinoma is investigated. Material and methods Tissue microarrays were generated from 219 thyroid carcinomas distributed as follows: papillary thyroid carcinoma (175), follicular thyroid carcinoma (11), medullary thyroid carcinoma (11), Hurthle cell carcinoma (three), poorly differentiated thyroid carcinoma (PTDC; nine), and anaplastic thyroid carcinoma (ATC; 10). Immunohistochemistry for SOX2 was done and examined for nuclear staining. The results were analysed.  Results SOX2 immunostaining was positive in one PDTC (out of nine; 11.1%) and in three ATC (out of 10; 30%). The rest of the thyroid cancers showed no immunostaining for SOX2. Conclusion The study represents for the first time SOX2 immunostaining on a large number of thyroid carcinomas. We discovered that SOX2 immunostaining is found in PDTC and ATC while SOX2 immunostaining is lacking in other thyroid cancer. SOX2 may be a marker of loss of differentiation in thyroid carcinoma. In vitro as well as in vivo molecular studies are required to explore the possible role of SOX2 in thyroid carcinoma.