From balance to imbalance: disruption of plasma glutathione concentration in micropapillary thyroid carcinoma.

BACKGROUND: Despite the presence of evidence that establishes a strong correlation between oxidative stress and thyroid cancer, there exists a scarcity of research that investigates the specific role of glutathione as an important antioxidant in this particular context. The objective of this study was to assess the altered balance of oxidative stress in cases of thyroid cancer, which includes both papillary thyroid carcinoma (PTC) and micro PTC (mPTC), by examining and comparing the total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), reduced glutathione (GSH), oxidized glutathione (GSSG), and GSSG/GSH ratio with those of individuals diagnosed with multinodular goiter (MNG) as well as Healthy subjects. MATERIALS AND METHODS: Plasma samples were collected from 92 patients (23 mPTC, 23 PTC, 23 MNG, 23 Healthy). The levels of TAC, TOS, GSH, and GSSG were measured using a commercial assay kits, and the OSI and GSSG/GSH ratio were calculated for each sample. Statistical analyses were performed to compare the oxidative stress between the groups. RESULTS: The plasma levels of TOS were significantly higher in the mPTC, PTC, and MNG groups compared to the Healthy individuals (p < 0.05). The OSI in the mPTC and PTC groups showed a significant increase compared to the Healthy group (p < 0.05). The levels of GSH in mPTC and PTC were markedly lower compared to the Healthy subjects (p < 0.01). Interestingly, the concentration of GSH in mPTC was found to be considerably lower than in PTC and MNG patients (p < 0.01). CONCLUSION: These findings indicate that GSH may be a useful biomarker for evaluating oxidative stress and antioxidant system status in patients with PTC, especially mPTC. Low levels of GSH may indicate increased levels of oxidative stress, which may contribute to the development and progression of mPTC to PTC.

Validation of Reference Genes for Normalization of Relative qRT-PCR Studies in Papillary Thyroid Carcinoma.

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) in thyroid tumors require accurate data normalization, however, there are no sufficient studies addressing the suitable reference genes for gene expression analysis in malignant and normal thyroid tissue specimens. The purpose of this study was to identify valid internal control genes for normalization of relative qRT-PCR studies in human papillary thyroid carcinoma tissue samples. The expression characteristics of 12 candidate reference genes (GAPDH, ACTB, HPRT1, TBP, B2M, PPIA, 18SrRNA, HMBS, GUSB, PGK1, RPLP0, and PGM1) were assessed by qRT-PCR in 45 thyroid tissue samples (15 papillary thyroid carcinoma, 15 paired normal tissues and 15 multinodular goiters). These twelve candidate reference genes were selected by a systematic literature search. GeNorm, NormFinder, and BestKeeper statistical algorithms were applied to determine the most stable reference genes. The three algorithms were in agreement in identifying GUSB and HPRT1 as the most stably expressed genes in all thyroid tumors investigated. According to the NormFinder software, the pair of genes including 'GUSB and HPRT1' or 'GUSB and HMBS' or 'GUSB and PGM1' were the best combinations for selection of pair reference genes. The optimal number of genes required for reliable normalization of qPCR data in thyroid tissues would be three according to calculations made by GeNorm algorithm. These results suggest that GUSB and HPRT1 are promising reference genes for normalization of relative qRT-PCR studies in papillary thyroid carcinoma.

Circulating levels of PTEN and KLLN in papillary thyroid carcinoma: can they be considered as novel diagnostic biomarkers?

PURPOSE: PTEN and KLLN are two tumor suppressor genes located in 10q23, share a bidirectional promoter and have roles in carcinogenesis. Formerly, the role of PTEN mutations and KLLN epimutations were identified in incidence of thyroid lesions in individuals with Cowden syndrome, a rare autosomal dominant inherited disorder. This study is the first of its type to assess PTEN and KLLN circulating levels in patients with sporadic papillary thyroid carcinoma (PTC) and compare to patients with multinodular goiter (MNG) and healthy individuals. METHODS: Plasma levels of PTEN and KLLN were determined by enzyme-linked immunosorbent assay in three groups consisted of PTC (n = 33), MNG (n = 26) and healthy persons (n = 30). The association of demographic/pathological characteristics with the levels of PTEN and KLLN were evaluated. RESULTS: A significant lower plasma levels of PTEN and KLLN were observed in PTC patients compared with those of healthy persons (PTEN, 9.43 ± 3.20 vs. 16.96 ± 1.28 ng/ml, P = 0.000; KLLN, 1.81 ± 0.83 vs. 2.57 ± 1.09 ng/ml, P = 0.005), while no statistical difference was found between PTC and MNG groups. Patients with MNG lesion had significantly lower levels of PTEN/KLLN (PTEN, 9.62 ± 2.97 vs. 16.96 ± 1.28 ng/ml, P = 0.000; KLLN, 1.34 ± 0.86 vs. 2.57 ± 1.09 ng/ml, P = 0.000) compared to the healthy controls. The demographic/pathological characteristics did not demonstrate an association with the levels of PTEN and KLLN. CONCLUSIONS: The study suggests that the lowered levels of PTEN and KLLN are associated with both sporadic PTC and MNG tumorigenesis, but they cannot be considered as circulating biomarkers for differential diagnosis between malignancy and benignity in indeterminate thyroid nodules.

Anti-leukemic and anti-angiogenesis efficacy of arsenic trioxide in new cases of acute promyelocytic leukemia.

Arsenic trioxide is now considered the standard agent in treatment of refractory cases of acute promyelocytic leukemia (APL). This drug is also shown to have anti-angiogenesis effect against APL cells in vitro. This study evaluated clinical efficacy and anti-angiogenesis effect of arsenic trioxide in 17 new cases of APL. Arsenic trioxide was given in a dosage of 0.15 mg kg(-1) and remission rate, survival rate, toxicities and effect on vascular density of bone marrow was studied. The bone marrow vascular density was examined using immunohistochemistry for von Willebrand Factor (vWF) and CD31 markers. Bone marrow vascular density was determined by calculating mean vessel number in 3 hot spot, high power microscopic fields. Bone marrow vascular density was reduced as identified by anti-vWF immunohistochemical staining (Mean before treatment = 201.6 mm(-2) +/- 20.4 (SEM), mean after treatment = 109.4 +/- 17.2 (SEM), p < 0.001) and anti-CD31 immunostaining (mean before treatment = 199.17 mm(-2) +/- 21.5 (SEM), mean after treatment = 99.5 mm(-2) +/- 22.1 (SEM), p < 0.05). Treatment efficacy results showed 100% complete remission rate after median of 30 days and 72% survival rate after median 860 days of follow-up. Main toxicities included hyper-leukocytosis, hepatic toxicity and APL differentiation syndrome. The results imply that arsenic trioxide is an effective anti-leukemia and anti-angiogenesis agent in new cases of APL.