Expression of cancer stem cell markers in tall cell variant papillary thyroid cancer identifies a molecular profile predictive of recurrence in classic papillary thyroid cancer.

Abstract Background Tall cell variant of papillary thyroid carcinoma is an aggressive subtype of papillary thyroid carcinoma. We examined expression of cancer stem cell markers in tall cell variant compared with other well-differentiated thyroid cancers. Methods Expression of cancer stem cell markers was examined in 572 thyroid tumors from The Cancer Genome Atlas Thyroid Cancer database and tall cell variant and papillary thyroid carcinoma tumors by immunohistochemistry. Results Expression of the PROM1 gene, encoding the cancer stem cell marker CD133, was elevated in tall cell variant compared to classic papillary thyroid carcinoma in a large cohort of unmatched samples from The Cancer Genome Atlas Thyroid Cancer database (P Conclusion Tall cell variant of papillary thyroid carcinoma has increased expression of cancer stem cell markers compared to classic papillary thyroid carcinoma. The tall cell variant-like cancer stem cell gene signature identified a molecular subtype of classic papillary thyroid carcinoma that has a worse recurrence-free survival.