Papillary Thyroid Carcinoma: A Malignant Tumor with Increased Antioxidant Defense Capacity

Abstract

Papillary thyroid carcinoma (PTC) is the commonest thyroid malignancy worldwide for which the radiation exposure is the most influential risk factor. The levels of oxidative stress in PTC are not well characterized on the tissue level. The objective of this study was to evaluate total oxidant status (TOS) and total antioxidant status (TAS) in PTC and benign goiter (BG) tissues and to examine their association with clinicopathological characteristics. Tumor and normal thyroid tissue samples were collected from 59 PTC patients, and goiter tissues were collected from 50 BG patients. TOS and TAS were quantified in the tissue homogenates by spectrophotometric assays. TOS values in tumor tissues did not differ significantly from normal and goiter tissues; however, PTC tissues have significantly higher TAS values than normal and goiter tissues. TOS values correlated with retrosternal growth in BG patients. The significant correlations were found between TOS and TAS values and thyroid function parameters. In 17 PTC patients with multiple tumor foci (multicentric phenotype), TAS values were significantly lower, compared to 42 patients with unicentric PTC. TAS and TOS are the most useful predictors of thyroid capsular invasion by PTC. The age, sex, body mass index, smoking, familial history of thyroid disease and nodule size did not influence TOS and TAS in PTC or BG patients. In conclusion, we show the profiles of TOS and TAS in PTC and BG tissues. Importantly, PTC tissues possess increased antioxidant capacity. The redox status influences the parameters of the thyroid function and tumor's biological behavior.

The Influence of Oxidative Stress on Thyroid Diseases

“…In turn, total oxidant status (TOS) is based on the oxidation of ferrous ion to ferric ion in the presence of various oxidants. It reflects the oxidation state of bodily fluids, represented by the level of radicals [66]. Oxidative stress index (OSI) is a measure of oxidative stress, calculated as the ratio of total oxidant status to total antioxidant status and therefore represents the overall oxidation state of the body [67].…”

Contribution of Glycation and Oxidative Stress to Thyroid Gland Pathology—A Pilot Study

“…The decrease of activity of glutathione peroxidase can stem from lowered level of reduced glutathione in erythrocytes and plasma. According to Rovcanin [33] and Yu et al [25], oxidative stress, apart from its physiological role, accompanies thyroid cancers and influences the progression of the disease.…”

“…It seems that cancer tissues are more capable of getting rid of free radicals than healthy and benign goitre tissues. Rovcanin [33] suggests that PTC tissue has efficient antioxidative potential to counteract harmful action of free radicals synthesised by the thyroid gland. An increased capability of antioxidative defence can cover up an increased production of free radicals in cancer tissue, which may account for lack of significant differences in overall oxidative cell state between tumor and control tissues.…”

Impact of Essential and Toxic Trace Metals on Thyroid Health and Cancer: A Review

“…Effective treatment of TC requires a surgical approach as the only potential curative method, which can be supplemented with adjuvant radioactive iodine ( 131 I) therapy or, in some cases, with chemotherapy (Carling and Udelsman 2014). Nowadays, the molecular-genetic and biochemical characterization of thyroid tumors (Rovcanin et al 2016a(Rovcanin et al , 2016b(Rovcanin et al , 2019(Rovcanin et al , 2020) is taking place in many research centers (Hunt 2005;Nikiforov and Nikiforova 2011;Nixon et al 2017;Navas-Carrillo et al 2017), offering promising early diagnostic, prognostic, and therapeutic modalities, which could markedly improve the current position (D'Cruz et al 2018). Taking into account that TC is a frequent malignancy in most countries, further fundamental and applied research is necessary to provide valuable scientific data about the nature of the disease and treatment modalities, especially in terms of predicting disease evolution and identifying asymptomatic individuals.…”