Cancer Biomarkers - Volume 28, issue 2

Authors: Gui, Si-Jie | Ding, Ru-Lei | Wan, Yan-Ping | Zhou, Li | Chen, Xu-Jun | Zeng, Gu-Qing | He, Chao-Zhu

Article Type: Research Article

Abstract: BACKGROUND: Radioresistance leads to treatment failure in patients with nasopharyngeal carcinoma (NPC). Thus, enhancing the radiosensitivity of NPC cells would likely increase the effectiveness of radiotherapy. Annexin VII (Annexin A7, ANXA7) might be a tumor promoter in NPC but its functions in radiosensitivity remain unclear. METHODS: NPC cell lines CNE2-shANXA7 and CNE2-pLKO.1 were generated and CNE2-shANXA7 nude mice xenograft tumor models were established. The main effects and molecular mechanisms of ANXA7 knockdown in NPC radiosensitivity were studied in vitro and in vivo by analyzing cell viability, clonogenicity, apoptosis, cell cycle distribution, tumor radioresponse and immunohistochemistry assay. RESULTS: …ANXA7 knockdown revealed potentially enhanced NPC cell radiosensitivity via apoptosis and increased the cell number at the G2/M phase. In the xenograft model, NPC cells with ANXA7 knockdown were dramatically sensitive to irradiation and tumor growth was significantly suppressed. Compared to CNE2-pLKO.1 xenografts, CNE2-shANXA7 showed more γ -H2AX foci and less phospho-DNA PKcs. CONCLUSIONS: ANXA7 knockdown increased the radiosensitivity of NPC by enhancing apoptosis, modulating the cell cycle distribution into more radiosensitive phases, promoting DNA damage, and inhibiting repair. We showed that decreased ANXA7 levels enhanced radiosensitivity and provided insights into the therapeutic targets for NPC radiotherapy. Show more

Keywords: Nasopharyngeal carcinoma, radiosensitivity, annexin VII

DOI: 10.3233/CBM-190739

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 129-139, 2020

Authors: Lyu, Jia | Zhu, Yongzhe | Zhang, Qi

Article Type: Research Article

Abstract: OBJECTIVE: Renal cell carcinoma (RCC) is the most common malignancy involving the kidneys and a major cause of cancer mortality. The involvement of microRNA (miRNA) expression in the tumorigenesis and progression of RCC still not been previously highlighted. We aimed to explore the potential role of miR-222-3p in renal cell carcinoma (RCC). METHOD: We first found that miR-222-3p was elevated significantly in the RCC tissues as compared to the non-tumor counterparts. We also found that a higher level of miR-222-3p in different RCC cell lines than the HK-2 cells. RESULTS: In vitro validation …experiment using miR-222-3p mimic molecules significantly induced expression of EMT marker vimentin and downregulated E-cadherin in both 769-P and 786-O RCC cells. In contrary, when miR-222-3p was downregulated by its inhibitor, the reverse observations were made. We then demonstrated a reversal association between the expression level of miR-222-3p and TIMP2/ERK where TIMP2 functions as a tumor suppressor. In a small cohort of 45 clinical samples, we found that miR-222-3p expression level was elevated and was associated with a poorer survival of the patients. Patients with higher miR-222-3p expression showed had a statistically shorter overall survival than those patients of lower miR-222-3p level (HR, 5.789; p = 0.02). CONCLUSION: Collectively, we showed that miR-222-3p functioned as a tumor progression marker and could be a target for future drug development. Show more

Keywords: miR-222-3p, malignant renal cell carcinoma, epithelial-to-mesenchymal transition, TIMP2/AKT axis

DOI: 10.3233/CBM-190264

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 141-149, 2020

Authors: Lin, Xia | Ling, Qing | Lv, Yunfei | Ye, Wenle | Huang, Jiansong | Li, Xia | Guo, Qi | Wang, Jinghan | Li, Zhongqi | Jin, Jie

Article Type: Research Article

Abstract: BACKGROUND: The interest in plasma biomarkers has increased recently. Plasma exosome-derived microRNA-532 is aberrantly expressed in a variety of human cancers and has the prognostic value in many solid tumors. However, the prognostic impact of the expression value on AML remains unclear. OBJECTIVE: The aim of this study is to investigate the prognostic value of exosome-derived microRNA-532 in AML patients. METHODS: We performed the real-time PCR to quantify exosome-derived microRNA-532 in plasma of 198 AML patients. To assess the prognostic value, we performed Cox regression analyses in the context of well-established clinical and …molecular markers. Cellular metabolic profile was conducted to help us understand the biological insight of its expression. RESULTS: The expression level was not associated with white blood cell counts, age, FAB subtypes, cytogenetic risk groups and genes of FLT3-ITD , NPM1 , CEBPA and DNMT3A mutations. Interestingly, high expressers had a favorable overall survival in the univariate analysis. This prognostic value was testified in the multivariate analysis. Moreover, up-regulation of miR-532 was negatively associated with cellular energy like fructose and glutamine. CONCLUSION: We found plasma exosome-derived microRNA-532 can be used as a novel survival predictor for acute myeloid leukemia. Show more

Keywords: Acute myeloid leukemia, exosome, microRNAs

DOI: 10.3233/CBM-191164

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 151-158, 2020

Authors: Stamenkovic, Srdjan | Cheng, Jie | Surowy, Harald | Burwinkel, Barbara | Gündert, Melanie

Article Type: Research Article

Abstract: BACKGROUND: Minimal invasive blood-based molecular markers are evaluated as promising biomarkers in malignant diseases these days. OBJECTIVE: In this pilot study, we investigated the potential of cell-free DNA (cfDNA) concentration and cell-free DNA Integrity (cfDI) as blood-based diagnostic markers for ovarian cancer patients in a retrospective study cohort. METHODS: cfDNA concentration and cfDI were determined in the plasma of 37 ovarian cancer patients and 28 healthy controls, by measuring ALU and LINE1 repetitive DNA elements using quantitative real-time PCR. RESULTS: A high correlation was observed between the results of ALU …and LINE1. The correlated co-efficiency between the values of cfDNA concentration and cfDI was 0.86 and 0.71. As for the results between cases and controls, no or just borderline significant difference was observed in cfDI after age adjustment (P = 0.40 for ALU and P = 0.05 for LINE1) while cfDNA concentration showed a significant difference between ovarian cancer patients and healthy controls groups (P = 0.03 for ALU and P = 3.00 E-03 for LINE1). cfDNA concentration of ALU and LINE1 had an AUC of 0.81 (0.70–0.91). ALU and LINE1 cfDI reached an AUC of 0.60 (95% CI: 0.46–0.73). The combination of these markers reached the best diagnostic power with an AUC of 0.84. CONCLUSIONS: cfDNA variables might be potentially diagnostic biomarkers in ovarian cancer, in combination with additional molecular markers. However, further studies are needed to confirm the diagnostic ability of cfDNA variables (cfDNA concentration and cfDI). Show more

Keywords: Ovarian cancer, diagnostic marker, cell free DNA concentration, cell free DNA integrity

DOI: 10.3233/CBM-191018

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 159-167, 2020

Authors: Liang, Rui | Tang, Youjia

Article Type: Research Article

Abstract: BACKGROUND: Glioma is considered to be one of the most common and lethal malignant brain tumors, accounting for 40% to 50% of brain tumors. Long non-coding RNAs (lncRNAs) have been widely proved to play an irreplaceable role in the tumorigenesis and progression. Nevertheless, the role of LINC00467 in glioblastoma remained unclear. AIM: The current study was aimed to explore the functional mechanism of LINC00467 in glioblastoma. METHODS: The expression of LINC00467/miR-339-3p/IP6K2 glioblastoma tissues and cells was evaluated by RT-qPCR. The protein expression of genes (cleaved PARP, PARP, cleaved caspase 3, caspase 3, Bax, …Bcl-2 and IP6K2) was measured by western blot assay. Then role of LINC00467 was demonstrated by EdU, colony formation, flow cytometry and TUNEL assays. The relationship between miR-339-3p and LINC00467/IP6K2 was validated by RNA pull down and luciferase reporter assays. RESULTS: The expression of LINC00467 was upregulated in glioblastoma tissues and cells. LINC00467 knockdown suppressed cell proliferation but activated cell apoptosis. Further, LINC00467 high expression was associated with shorter overall survival rate in glioblastoma patients. Further, LINC00467 could bind with miR-339-3p, and IP6K2 was targeted by miR-339-3p. IP6K2 expression was regulated by LINC00467/miR-339-3p in a ceRNA pattern. Moreover, LINC00467 could regulate the development of glioblastoma via miR-339-3p/IP6K2 axis. CONCLUSIONS: LINC00467 knockdown repressed cell proliferation but stimulated cell apoptosis in glioblastoma via miR-339-3p/IP6K2 axis, which may enlighten to find a novel therapeutic tactic for glioblastoma patients. Show more

Keywords: LINC00467 miR-339-3p, IP6K2, glioblastoma

DOI: 10.3233/CBM-190939

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 169-180, 2020

Authors: Li, Yanshi | Lu, Tao | Hu, Guohua

Article Type: Research Article

Abstract: OBJECTIVE: We performed differential gene screening for lymphatic metastasis of hypopharyngeal carcinoma by gene sequencing. We also aimed to investigate the expression and clinicopathological significance of the screened gene in hypopharyngeal carcinoma lymphatic metastasis. METHODS: The clinicopathological characteristics of 98 patients with hypopharyngeal carcinoma were collected to make survival analysis by Kaplan-Meier & log-rank test. Six cases of tumor tissues from patients with or without lymphatic metastasis were used for gene sequencing of differentially expressed genes. The most frequently differently expressed genes were validated by RT-PCR and Western blot in another 20 patients diagnosed for hypopharyngeal …carcinoma. A total of 70 cases of hypopharyngeal carcinoma tumor tissues and normal tissues were investigated to examine the immunohistochemical expression and to explore the prognostic value by Kaplan-Meier & log-rank test and Cox’s test. RESULTS: Lymphatic metastasis has been proved to cause a reduction in postoperative survival of patients with hypopharyngeal carcinoma. The results of gene sequencing analysis showed that Raf-1 was a differentially expressed gene in lymphatic metastasis of hypopharyngeal carcinoma. Moreover, the expression of Raf-1 was significantly up-regulated in tumor tissues of lymphatic metastasis patients compared to non-lymphatic metastasis tumor tissues and normal tissues. Meanwhile, Raf-1 had been verified to be an independent risk factor affecting the prognosis of hypopharyngeal carcinoma. CONCLUSIONS: For the first time, we investigated Raf-1 as an independent prognostic risk factor of lymphatic metastasis in hypopharyngeal carcinoma. It suggests that Raf-1 may serve as an important potential biomarker in preventing and diagnosing lymphatic metastasis in patients with hypopharyngeal carcinoma and improving the prognosis of patients. Show more

Keywords: Hypopharyngeal carcinoma, gene sequencing, Raf-1

DOI: 10.3233/CBM-191238

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 181-191, 2020

Authors: Taniguchi-Ponciano, Keiko | Gomez-Apo, Erick | Chavez-Macias, Laura | Vargas, Guadalupe | Espinosa-Cardenas, Etual | Ramirez-Renteria, Claudia | Ferreira-Hermosillo, Aldo | Sosa, Ernesto | Silva-Román, Gloria | Peña-Martínez, Eduardo | Andonegui-Elguera, Sergio | Vargas-Chavez, Sonia | Santiago-Andres, Yorgui | Peralta, Raul | Marrero-Rodríguez, Daniel | Mercado, Moises

Article Type: Research Article

Abstract: BACKGROUND: Clinically non-functioning Pituitary Adenomas (NFPA) are among the most common neoplasms of the sellar region. They usually present with compressive symptoms such as headache and visual field defects and not infrequently, are found incidentally. NFPA are classified as gonadotropinomas, null cell adenomas, according to their immunohistochemical phenotype. The molecular alterations responsible for the development of these lesions are incompletely understood, and there is scarce information regarding the molecular alterations and markers. OBJECTIVE: We carried out an in-silico analysis aimed at identifying the molecular alterations in NFPA and to discover new molecular markers. …METHODS: Twenty-three microarray libraries were analyzed. Fourteen correspond to NFPA and 9 to control tissue gland. They were analyzed using Partek Genomic Suite to identify differentially expressed genes and WebGestalt and Metascape to understand the meaning behind the gene lists. RESULTS: Pituitary adenomas showed a markedly different transcriptome compared to the non-tumoral gland, regardless of their putative immunophenotype. Genes related to calcium metabolism such as CACNA2D4, immune-related CXCR4, and stem cell-related KLF8 and PITX2 were altered. CONCLUSIONS: Differentially expressed calcium metabolism and immune-related genes in NFPA represent attractive molecular markers and potential therapeutic targets. Show more

Keywords: Non-functioning pituitary adenomas, null cell, gonadotropinomas, molecular markers

DOI: 10.3233/CBM-191121

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 193-199, 2020

Authors: Chen, Jiewei | He, Qingmei | Wu, Peishan | Fu, Jianchang | Xiao, Yongbo | Chen, Keming | Xie, Dan | Zhang, Xinke

Article Type: Research Article

Abstract: BACKGROUND: Zinc finger MYND (Myeloid, Nervy and DEAF-1)-type containing 8 (ZMYND8) is closely correlated with tumor proliferation and invasiveness. However, its prognostic value has not been estimated in colorectal cancer (CRC). OBJECTIVE: We aimed to elucidate the prognostic significance of ZMYND8 expression and the pN and pM classification supplemented by its expression in CRCs. METHODS: The candidate gene ZMYND8 is identified by TCGA database and GEO database, and then we retrospectively evaluated the status and prognostic significance of ZMYND8 expression of 174 patients with CRC. RESULTS: Online data showed high …expression of ZMYND8 is closely correlated with worse overall survival. Our study revealed high expression of ZMYND8 in CRC patients was significantly associated with worse overall and disease-free survival (P < 0.05), and was an independently adverse prognostic factor for overall survival (P < 0.001) and disease-free survival (P = 0.001) by univariate and multivariate analysis. C-index to combined prognostic model containing the pN, pM classification supplemented by the status of ZMYND8 expression showed improved predictive ability comparing with the pN and pM classification model (C-index of 0.597 vs. 0.545, respectively). CONCLUSION: The combined prognostic model could improve the ability to determine the clinical outcome of patients with CRC. Show more

Keywords: ZMYND8, prognosis, C-index, colorectal cancer

DOI: 10.3233/CBM-191261

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 201-211, 2020

Authors: Alsofyani, Abeer A. | Dallol, Ashraf | Farraj, Suha A. | Alsiary, Rawiah A. | Samkari, Alaa | Alhaj-Hussain, Baraa T. | Khan, Jalaluddin Azam | Al-Maghrabi, Jaudah | Al-Khayyat, Shadi S. | Alkhatabi, Heba | Elaimi, Aisha | Buhmeida, Abdelbaset | Johargy, Ayman Khalid | Abuzenadah, Adel M. | Azhar, Esam I. | Al-Qahtani, Mohammed H.

Article Type: Research Article

Abstract: BACKGROUND: Oral tongue squamous cell carcinoma (OTSCC) is a highly aggressive malignancy characterized by frequent recurrence, poor survival with relatively few therapeutic options due to the late diagnosis in many cases. OBJECTIVES: Understanding the molecular pathways underlying OTSCC tumourigenesis and the discovery of diagnostic and/or prognostic biomarkers. METHODS: We performed high-throughput mutational analysis of 44 OTSCC formalin-fixed paraffin-embedded (FFPE) cases using the Cancer Hotspots Panel (CHP) v2 on the Ion Torrent™platform. We determined the frequency of human papilloma virus (HPV) using PCR and Epstein bar virus (EBV) positivity using immunohistochemistry. As a control …for EBV infection we screened matched non-tumourous tissues. RESULTS: Sequencing analysis identified missense, nonsense and frameshift mutations in TP53 (66%), PIK3CA (27%), CDKN2A (25%), EGFR (18%), and PTEN (14%). Interestingly, no significant associations were found between damaging mutations and clinicopathological data. A total of 10/44 of the OTSCC samples (23%) tested was positive for HPV18 DNA. OTSCC patients with positive HPV infection had worse overall survival compared to HPV-negative cases as determined by Kaplan-Meier survival (p = 0.023). Furthermore, EBNA1 expression showed a strong tumour-enriched expression pattern in 20 out of 21 samples (95%) in the epithelial compartments of the tissues analysed. CONCLUSIONS: Taken together, this study highlights that the two most common events in OTSCC are TP53 mutations and EBV positivity. Helping to understand the contribution of TP53 mutations and EBV infection events could serve as useful biomarkers for OTSCC. Show more

Keywords: Tongue cancer, oral cancer, EBV, HPV, biomarkers

DOI: 10.3233/CBM-190897

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 213-220, 2020

Authors: Cai, Xiaoniao | Yu, Leilei | Chen, Zhen | Ye, Fangpeng | Ren, Zonghai | Jin, Peisheng

Article Type: Research Article

Abstract: Recently, Arsenic trioxide (ATO) has been reported as an efficient drug for suppression of cancer cell growth. Existing studies revealed the extensive involvement of microRNAs (miRNAs) in initiation and development of hepatocellular carcinoma (HCC). However, the potential correlation between ATO and miRNAs in HCC progression remains to be explored. To conduct our research, we applied a qRT-PCR analysis to find miRNAs that were upregulated in HCC cells treated with ATO. In our present study, miR-1294 was found to be significantly upregulated in ATO-treated HCC cells. To confirm the function of ATO and miR-1294 in HCC progression, gain-of function assays were …designed and conducted. As expected, proliferative ability of ATO-treated HCC cells was markedly weakened compared to DMSO-treated HCC cells. More importantly, proliferation was further suppressed in ATO-induced HCC cells after overexpression of miR-1294. Through bioinformatics analysis, some potential targets of miR-1294 were predicted. Further investigation revealed that Pim-1 proto-oncogene (PIM1) and TEA domain transcription factor 1 (TEAD1) were two downstream targets of miR-1294 and could be negatively regulated by ATO. Functionally, we determined that cell proliferation and apoptosis resistance suppressed by miR-1294 and ATO were recovered by introduction of TEAD1 and PIM1. Collectively, this study revealed that a novel ATO-miR-1294-TEAD1/PIM1 axis regulated HCC cell growth, offering a potential insight into the HCC therapy. Show more

Keywords: ATO, hepatocellular carcinoma, miR-1294, TEAD1, PIM1

DOI: 10.3233/CBM-190490

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 221-230, 2020

Authors: Wen, Ji-Feng | Jiang, Yong-Qing | Li, Chao | Dai, Xian-Kui | Wu, Tong | Yin, Wen-Zhe

Article Type: Research Article

Abstract: Chemotherapy is one of the primary treatments used against cancer. Cisplatin is a conventional chemotherapy drug used to treat osteosarcoma; however, due to the development of cisplatin resistance, advantageous therapeutic outcomes and prognosis of osteosarcoma remain low. Thus, investigation of the specific targeted therapies to circumvent the anti-chemoresistance of osteosarcoma depends on understanding the molecular mechanisms underlying cisplatin resistance. Tumor cells display an increased utilization of glycolysis rather than oxidative phosphorylation. This phenomenon is called the “Warburg effect,” which presents a survival advantage for tumor cells, leading to chemoresistance. To date, the molecular mechanism underlying osteosarcoma cisplatin resistance remains to …be fully elucidated. In this study, we reported the significant down-regulation of the long noncoding RNA-Suppressing Androgen Receptor in Renal Cell Carcinoma (lncRNA-SARCC) in the cells of osteosarcoma and in the specimens from osteosarcoma patients. Moreover, we observed a negative correlation between the lncRNA-SARCC and cisplatin resistance in the osteosarcoma tissues. Overexpression of the lncRNA-SARCC sensitizes osteosarcoma cells to cisplatin. From microarray analysis, we screened several miRNAs, which are significantly regulated by the lncRNA-SARCC in osteosarcoma cells, and revealed that lncRNA-SARCC promoted microRNA-43 (miR-143) expression in osteosarcoma. Interestingly, miR-143 showed the same expression pattern with the lncRNA-SARCC in osteosarcoma patient specimens. By establishing a cisplatin-resistant cell line from Sarcoma Osteogenic-2 (Saos-2), we found the cisplatin-resistant cells with down-regulated expressions of the lncRNA-SARCC and miR-143, but with a higher glycolysis rate compared to that in parental cells. We identified the glycolysis key enzyme, Hexokinase 2 (HK2), as a direct target for miR-143 in osteosarcoma. Restoration of the HK2 expression in the lncRNA-SARCC-overexpressing osteosarcoma cells reversed cisplatin resistance, suggesting that lncRNA-SARCC-mediated cisplatin sensitivity may be via glycolysis in the miR-143-inhibited osteosarcoma cells. Finally, results from both in vitro and in vivo xenograft models demonstrated that the lncRNA-SARCC was an effective therapeutic agent for overcoming cisplatin resistance in osteosarcoma. Our findings suggest an essential axis of the lncRNA-SARCC-miR-143-HK2 in regulation of osteosarcoma chemosensitivity, presenting the lncRNA-SARCC as a new therapeutic target against cisplatin-resistant osteosarcoma. Show more

Keywords: lncRNA-SARCC, microRNA-143, cisplatin resistance, osteosarcoma, the Warburg effect

DOI: 10.3233/CBM-191181

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 231-246, 2020

Authors: Lv, Jingjing | Zhang, Haitao | Gao, Zhimei | Zhang, Xinyan | Huang, Xin | Jia, Xiaojuan

Article Type: Research Article

Abstract: BACKGROUND: Gastric cancer is a prevalent malignant around the world. Aberrantly expression of microRNAs (miRNAs) contributes to the progression of tumors. The aim of this study was to investigate the expression and role of miR-892a in gastric cancer. METHODS: A total of 119 gastric cancer patients were enrolled in this study. And the expression of miR-892a in gastric cancer tissues and cells was measured using RT-qPCR analysis. Kaplan-Meier plotter and multivariate Cox regression analysis were used to explore the prognostic value of miR-892a in gastric cancer. The biological function of miR-892a in gastric cancer cells was …evaluated using CCK-8 assays and Transwell assays. RESULTS: The expression of miR-892a was high-expressed in gastric cancer tissues and cells. The miR-892a expression was associated with tumor size, differentiation, lymph node metastasis, and TNM stages. Gastric cancer patients with high miR-892a expression showed a short overall survival rate. Overexpression of miR-892a promoted cell proliferation, migration, and invasion of gastric cancer cells. CONCLUSION: miR-892a was upregulated and predictor of poor prognosis in gastric cancer patients. The miR-892a in gastric cancer cells significantly promoted cell proliferative, migratory, and invasive properties. Furthermore, miR-892a may be served as a prognostic marker as well as a therapeutic target for gastric cancer. Show more

Keywords: Gastric cancer, miR-892a, migration, prognosis, proliferation, invasion

DOI: 10.3233/CBM-191323

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 247-254, 2020

Authors: Iancu, Iulia V. | Botezatu, Anca | Plesa, Adriana | Huica, Irina | Fudulu, Alina | Albulescu, Adrian | Bostan, Marinela | Mihaila, Mirela | Grancea, Camelia | Manda, Dana Alice | Dobrescu, Ruxandra | Vladoiu, Susana Vilma | Anton, Gabriela | Badiu, Corin Virgil

Article Type: Research Article

Abstract: PURPOSE: DNA methylation plays an important role in thyroid oncogenesis. The aim of this study was to investigate the connection between global and local DNA methylation status and to establish the levels of important DNA methylation regulators (TET family and DNMT1 ) in thyroid tumours: follicular adenoma-FA, papillary thyroid carcinoma-PTC (classic papillary thyroid carcinoma-cPTC and papillary thyroid carcinoma follicular variant fvPTC). METHODS: Global DNA methylation profile in thyroid tumours tissue (41 paired samples) was assessed by 5-methylcytosine and 5-hydroxymethylcytosine levels evaluation (ELISA), along with TETs and DNMT1 genes expression quantification. Also, it was …investigated for the first time TET1 and TET2 promoter’s methylation in thyroid tumours. BRAF V600E mutation and RET/PTC translocation testing were performed on all investigated samples. In vitro studies upon DNA methylation in K1 thyroid cancer cells were performed with demethylating agents (5-AzaC and vitamin C). RESULTS: TET1 and TET2 displayed a significantly reduced gene expression level in PTC, while DNMT1 gene presented a high level of expression. PTC samples presented increased levels of 5-methylcytosine and low levels of 5-hydroxymethylcytosine. 5-methylcytosine levels were associated with TET1/TET2 expression levels. TET1 gene expression was significantly lower in patients positive for BRAF mutation and with RET/PTC rearrangement. TET2 gene was found hypermethylated in thyroid carcinoma patients overall, especially in PTC-follicular variant samples (p = 0.0002), where TET2 gene expression levels were significantly reduced (p = 0.0031). Furthermore, the data indicate for all thyroid cancer patients a good sensitivity (81.08%) and specificity (86.49%) regarding the use of TET1 (p < 0.0001), and TET2 (71.79%, 64.10%, p = 0.0001) hypermethylation as biomarkers for thyroid oncogenesis. CONCLUSIONS: These results suggest that TET1/TET2 gene expression and methylation may serve as potential diagnostic tools for thyroid neoplasia. Our study showed that the methylation of TET1 increases in malignant thyroid tumours. fvPTC patients presented lower methylation levels compared to cPTC and could be a discriminatory factor between two cancer types and benign lesions. TET2 is a poorer discriminator between FA and fvPTC, but it can be useful for cPTC identification. K1-cells treated with demethylating agents showed a demethylation effect, especially upon TET2 gene. The cumulative effect of L-AA and 5-AzaC proved to have a potent combined demethylating effect on genes promoter’s activation and could open new perspectives for thyroid cancer therapy. Show more

Keywords: Papillary thyroid carcinoma, DNA methylation, TETs

DOI: 10.3233/CBM-190871

Citation: Cancer Biomarkers, vol. 28, no. 2, pp. 255-268, 2020