Osteopontin cytoplasmic immunoexpression is a predictor of poor disease-free survival in thyroid cancer

BackgroundOsteopontin (OPN) is expressed in various malignancies and may play an important role in tumorigenesis, tumour invasion, and metastasis in various malignancies including thyroid cancers. The objective of this study was to investigate the relationship between OPN immunoexpression and clinicopathological characteristics in thyroid lesions.Material and methodsParaffin blocks belonging to 160 patients with thyroid neoplasms were retrieved from the archive of the Department of Pathology at King Abdulaziz University, and King Faisal Specialist Hospital, Jeddah, Saudi Arabia. Immunohistochemistry was performed using anti-OPN antibody. Statistical tests were used to determine the relation of OPN immunoexpression to clinicopathological characteristics and survival.ResultsImmunostaining results showed that OPN was localised in the cytoplasm and nucleus with higher cytoplasmic expression. Cytoplasmic and nuclear OPN was higher in thyroid cancer than other lesions. Microcarcinoma variant of papillary thyroid carcinoma showed a lower OPN cytoplasmic level than other variants. OPN cytoplasmic expression was not associated with most of the clinicopathological parameters tests. However, OPN cytoplasmic overexpression was associated poor survival outcome (p < 0.001).ConclusionUpregulation of cytoplasmic OPN was associated with poor survival outcome and was an independent predictor of margin involvement and recurrence. Nuclear OPN expression was lower than cytoplasmic and was associated with extrathyroid extension of thyroid cancer. OPN plays a role in thyroid carcinoma and incoming research has to be focused on the mechanistic association with invasion and metastasis.