In this study, we analyzed NOX4 expression at the protein level by immunostaining in 134 thyroid tissues (48 thyroid carcinomas, 46 normal adjacent tissues, and 40 non-malignant thyroid tissues) to improve our understanding of the potential role of NOX4 as a predictive marker of aggressiveness in PTC. This evidence concerns the gene NOX4 and thyroid gland carcinoma.