RASSF1A promoter methylation is associated with increased risk of thyroid cancer: a meta-analysis

Diagnostic value of exfoliated tumor cells combined with DNA methylation in bronchoalveolar lavage fluid for lung cancer

BACKGROUND

To evaluate the diagnostic value of exfoliated tumor cells (ETCs) numbers combined with DNA methylation levels in bronchoalveolar lavage fluid (BALF) in lung cancer.

METHODS

BALF samples were collected from 43 patients with lung cancer and 23 with benign lung disease. ETCs were detected by the nano-enrichment method, and the methylation status of the short stature homeobox gene 2 (SHOX2) and the RAS association domain family 1, isoform A (RASSF1A) gene were detected by RT-PCR. The diagnostic value of each metric was evaluated by receiver operating characteristic curve analysis, specificity and sensitivity.

RESULTS

The sensitivity/specificity of RASSF1A and SHOX2 methylation detection were 44.12%/76.47% and 93.75%/87.50%, respectively. When "RASSF1A/SHOX2 methylation" was used as a positive result, the sensitivity increased to 88.24%, and the specificity decreased to 81.25%. When "RASSF1A + SHOX methylation" was used as positive, the sensitivity was reduced to 32.35%, but the specificity was increased to 100.00%. The sensitivity and specificity of ETCs detection in BALF were 89.47% and 16.67%, respectively. When "SHOX2/RASSF1A methylation + ETCs was used as a positive result, the sensitivity and specificity of the detection were 79.31% and 81.82%, respectively. When "SHOX2 + RASSF1A + ETCs" was used as positive, the sensitivity was 34.48% and the specificity was 90.91%. Receiver operating characteristic curve analysis showed that when SHOX2, RASSF1A methylation and ETCs were combined, the diagnostic sensitivity increased to 0.778.

CONCLUSION

ETCs counting in combination with SHOX2 and RASSF1A methylation assays in BALF samples has demonstrated excellent sensitivity for lung cancer diagnosis and is an effective complementary tool for clinical diagnosis of lung cancer.

A comprehensive diagnostic scheme of morphological combined molecular methylation under bronchoscopy

Methylated SHOX2 and RASSF1A genes are potential biomarkers for lung cancer diagnosis. Therefore, we explored the role of methylation detection combined with morphological bronchoscopic evaluation for lung cancer diagnosis. Bronchoscopy, methylation outcome, and pathological data were collected from 585 patients with lung cancer and 101 controls. The methylation status of the SHOX2 and RASSF1A genes were detected using real-time polymerase chain reaction quantification. Further, the sensitivity and area under the receiver operating characteristic curve of the three methods were analyzed. Among 686 patients, 57.1% had new lesions detected through bronchoscopy and 93.1% of these patients were diagnosed with malignant tumors. Besides, 42.9% of patients had no visible changes under bronchoscopy but there were still 74.8% of them diagnosed with malignant tumors. Bronchoscopy revealed that lung adenocarcinoma, lung squamous cell carcinoma, and small cell lung cancer mainly occurred in the upper and middle lobes. The sensitivity and specificity of methylation detection were 72.8% and 87.1% (vs. cytology 10.4% & 100%), respectively. Therefore, methylated SHOX2 and RASSF1A genes may be promising tumor markers in lung cancer diagnosis. Methylation detection can be an excellent supplementary tool for cytological diagnosis and, combined with bronchoscopy, could form a more effective diagnostic process.

Molecular features of aggressive thyroid cancer

Poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC) have a worse prognosis with respect to well differentiated TC, and the loss of the capability of up-taking ¹³¹I is one of the main features characterizing aggressive TC. The knowledge of the genomic landscape of TC can help clinicians to discover the responsible alterations underlying more advance diseases and to address more tailored therapy. In fact, to date, the antiangiogenic multi-targeted kinase inhibitor (aaMKIs) sorafenib, lenvatinib, and cabozantinib, have been approved for the therapy of aggressive radioiodine (RAI)-resistant papillary TC (PTC) or follicular TC (FTC). Several other compounds, including immunotherapies, have been introduced and, in part, approved for the treatment of TC harboring specific mutations. For example, selpercatinib and pralsetinib inhibit mutant RET in medullary thyroid cancer but they can also block the RET fusion proteins-mediated signaling found in PTC. Entrectinib and larotrectinib, can be used in patients with progressive RAI-resistant TC harboring TRK fusion proteins. In addition FDA authorized the association of dabrafenib (BRAF^V600E inhibitor) and trametinib (MEK inhibitor) for the treatment of BRAF^V600E-mutated ATC. These drugs not only can limit the cancer spread, but in some circumstance they are able to induce the re-differentiation of aggressive tumors, which can be again submitted to new attempts of RAI therapy. In this review we explore the current knowledge on the genetic landscape of TC and its implication on the development of new precise therapeutic strategies.

The Role of TSHR, PTEN and RASSF1A Promoters' Methylation Status for Non-Invasive Detection of Papillary Thyroid Carcinoma

Aim: We investigated whether a difference exists between TSHR, PTEN and RASSF1A methylation status in plasma of subjects with papillary thyroid cancer (PTC). Methods: Peripheral blood samples were collected from 68 patients with PTC and 86 healthy controls (HC). Thyroid cancer tissue and corresponding adjacent normal tissue methylation levels were analyzed. DNA methylation level changes in TSHR, PTEN and RASSF1A genes were analyzed by quantitative methylation-sensitive polymerase chain reaction. Results: We observed that the methylation level of TSHR was significantly higher in the thyroid cancer tissue compared to adjacent normal tissue (p = 0.040). TSHR methylation levels in the PTC group plasma samples were significantly higher compared to HC (p = 0.022). After surgery, PTC plasma samples showed lower TSHR and PTEN methylation levels compared to the levels before surgery (p = 0.003, p = 0.031, respectively). The TSHR methylation level was significantly higher in PTC with larger tumor size (>2 cm) (p < 0.001), and lymph node metastases (p = 0.01), lymphovascular invasion (p = 0.02) and multifocality (p = 0.013) 0ROC analysis revealed that the TSHR methylation level provides high accuracy in distinguishing PTC from HC (p = 0.022, AUC of 0.616). Conclusion: TSHR methylation in peripheral blood samples is expected to be a sensitive and specific minimally invasive tool for the diagnosis of PTC, especially in combination with other diagnostic means.

The Genomic Landscape of Thyroid Cancer Tumourigenesis and Implications for Immunotherapy

Thyroid cancer is the most prevalent endocrine malignancy that comprises mostly indolent differentiated cancers (DTCs) and less frequently aggressive poorly differentiated (PDTC) or anaplastic cancers (ATCs) with high mortality. Utilisation of next-generation sequencing (NGS) and advanced sequencing data analysis can aid in understanding the multi-step progression model in the development of thyroid cancers and their metastatic potential at a molecular level, promoting a targeted approach to further research and development of targeted treatment options including immunotherapy, especially for the aggressive variants. Tumour initiation and progression in thyroid cancer occurs through constitutional activation of the mitogen-activated protein kinase (MAPK) pathway through mutations in BRAF, RAS, mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) pathway and/or receptor tyrosine kinase fusions/translocations, and other genetic aberrations acquired in a stepwise manner. This review provides a summary of the recent genetic aberrations implicated in the development and progression of thyroid cancer and implications for immunotherapy.

Prediction of the Prognosis Based on Chromosomal Instability-Related DNA Methylation Patterns of ELOVL2 and UBAC2 in PTCs

Papillary thyroid carcinoma (PTC) is the most common malignant tumor of endocrine systems. Chromosomal instability (CIN) is crucial to the clinical prognoses of tumor patients. DNA methylation plays an important role in the regulation of gene expression and CIN. Based on PTC samples from The Cancer Genome Atlas database, we used multiple regression analyses to identify methylation patterns of CpG sites with the strongest correlation with gene expression. A total of 4,997 genes were obtained through combining the CpG sites, which were represented as featured DNA methylation patterns. In order to identify CIN-related epigenetic markers of PTC survival, we developed a method to characterize CIN based on DNA methylation patterns of genes using the Student’s t statistics. We found that 1,239 genes were highly associated with CIN. With the use of the log-rank test, univariate Cox regression analyses, and the Kaplan-Meier method, DNA methylation patterns of UBAC2 and ELOVL2, highly correlated with CIN, provided potential prognostic values for PTC. The higher these two genes, risk scores were correlated with worse PTC patient prognoses. Moreover, the ELOVL2 risk score was significantly different in the four stages of PTC, suggesting that it was related to the progress of PTC. The DNA methylation pattern associated with CIN may therefore be a good predictor of PTC survival.

Multidrug resistance affects the prognosis of primary epithelial ovarian cancer

Multidrug-resistant tumor cells can tolerate different structures, functions and antidrug action mechanisms, therefore, allowing these cells to respond to various structurally unrelated mechanisms of different chemotherapy drugs and to exhibit cross-resistance. The present study aimed to investigate the role of Multi-drug resistance gene (MDR1), Placental glutathione S-transferase-P1 (GSTP1), Lung resistance protein (LRP) and Ras association domain family member 1 (RASSF1A) in primary epithelial ovarian cancer (PEOC). The mRNA (protein) expression levels of MDR1, product P glycoprotein, LRP and GSTP1 were evaluated with reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis in all tissue samples, ovarian cancer cell line A2780 and A2780/DDP. Methylation-specific PCR (MSP) was used to detect RASSF1A gene methylation in all tissue samples. The resistance genes/proteins were either poorly or not expressed in A2780, however were highly expressed in A2780/DDP cell line. The expression of resistance genes/proteins decreased following different concentrations of zebularine-stimulated A2780/DDP. Hypermethylation and low expression of RASSF1A gene were detected in PEOC and A2780/DDP. Subsequent to being exposed to different concentrations of zebularine-stimulated A2780/DDP, the RASSF1A methylation level was decreased, while the unmethylation level was increased. The expression of RASSF1A gene/protein was gradually restored, and the gene/protein expression was enhanced with the increase in drug concentration. Multivariate logistic regression indicated that the expression level of gene LRP and GSTP1 was a risk factor for PEOC prognosis. Furthermore, the expression of LRP and GSTP1 in the negative-group survival curves was higher compared with the positive group. High expression of resistance genes may serve an important role in cancer primary resistance. Low expression caused by hyper-methylation of RASSF1A gene may serve an important role in cancer-acquired resistance in PEOC. The present study suggested that resistant gene expression may be a potential prognostic biomarker.

A RASSF1A-HIF1α loop drives Warburg effect in cancer and pulmonary hypertension

Hypoxia signaling plays a major role in non-malignant and malignant hyperproliferative diseases. Pulmonary hypertension (PH), a hypoxia-driven vascular disease, is characterized by a glycolytic switch similar to the Warburg effect in cancer. Ras association domain family 1A (RASSF1A) is a scaffold protein that acts as a tumour suppressor. Here we show that hypoxia promotes stabilization of RASSF1A through NOX-1- and protein kinase C- dependent phosphorylation. In parallel, hypoxia inducible factor-1 α (HIF-1α) activates RASSF1A transcription via HIF-binding sites in the RASSF1A promoter region. Vice versa, RASSF1A binds to HIF-1α, blocks its prolyl-hydroxylation and proteasomal degradation, and thus enhances the activation of the glycolytic switch. We find that this mechanism operates in experimental hypoxia-induced PH, which is blocked in RASSF1A knockout mice, in human primary PH vascular cells, and in a subset of human lung cancer cells. We conclude that RASSF1A-HIF-1α forms a feedforward loop driving hypoxia signaling in PH and cancer.

Protective effect of KLF15 on vascular endothelial dysfunction induced by TNF‑α

Atherosclerosis (AS) is a cardiovascular disease with a relatively high incidence rate. Krüppel-like factor 15 (KLF15) has a role in numerous pathological processes, including nephropathy, abnormal glucose metabolism and myocardial injury. The aim of the present study was to investigate the function of KLF15 in vascular endothelial dysfunction. MTT analyses, nitric oxide (NO) detection and cell adhesion detection kits were used to investigate the viability and adhesion of, and quantity of NO released by Eahy926 cells induced by tumor necrosis factor (TNF)-α, respectively. Reverse transcription-quantitative polymerase chain reaction and western blot analyses were performed to determine the expression levels of KLF15, endothelial nitric oxide synthase, monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), transforming growth factor-β1 (TGF-β1), phosphorylated (p-)transcription factor p65 (p65) and nuclear factor erythroid 2-related factor 2 (Nrf2). The results of the present study demonstrated that TNF-α was able to induce vascular endothelial dysfunction in Eahy926 cells at an optimum concentration of 10 ng/ml. Overexpression of KLF15 markedly enhanced cell viability in addition to the quantity of released NO of TNF-α-induced Eahy926 cells, and increased the expression levels of eNOS and Nrf2. Furthermore, overexpression of KLF15 markedly suppressed the rate of cellular adhesion, and downregulated levels of MCP-1, ICAM-1, TGF-β1 and p-p65 in TNF-α induced Eahy926 cells. In conclusion, the results of the present study suggested that overexpression of KLF15 in Eahy926 cells exhibited a protective effect against TNF-α induced dysfunction via activation of Nrf2 signaling and inhibition of nuclear factor κB signaling.

Associations of RASSF1A, RARβ, and CDH1 promoter hypermethylation with oral cancer risk: A PRISMA-compliant meta-analysis

BACKGROUND

Oral tumor is a heterogeneous group of tumors, in which it has several different histopathological and molecular features. Recently, genetic and epigenetic alterations are often detected in the development of oral cancer. Gene promoter hypermethylation leads to the silencing of cancer related genes without changes of genes sequence. To clarify the effect of RAS association domain family protein 1a (RASSF1A), retinoic acid receptor beta (RARβ), and E-cadherin (CDH1) promoter hypermethylation on the risk of oral cancer, we performed this meta-analysis.

METHODS

PubMed, Web of Science, Embase, and Chinese National Knowledge Infrastructure (CNKI) databases were retrieved to identify eligible articles. Stata 12.0 software was used to analyze extracted data of the included articles. Odds ratios (ORs) with the corresponding 95% confidence interval (95% CI) were calculated to evaluate the associations of RASSF1A, RARβ, and CDH1 promoter hypermethylation with oral cancer risk.

RESULTS

Around 23 literatures with 29 studies were included in the final meta-analysis, in which 12 studies were about RASSF1A promoter methylation, 4 studies were about RARβ promoter methylation, and 13 studies were about CDH1 promoter methylation. Overall, the results of this meta-analysis showed that there were significant associations between RASSF1A, RARβ, and CDH1 promoter hypermethylation and oral cancer risk (RASSF1A, OR = 11.8, 95% CI = 6.14-22.66; RARβ, OR = 20.35, 95% CI = 5.64-73.39; CDH1, OR = 13.46, 95% CI = 5.31-34.17). In addition, we found that RASSF1A promoter hypermethylation exerted higher frequency in the tongue tumor than other site tumor in mouth (RASSF1A, tongue tumor vs other site tumor in mouth, unmethylation vs methylation, OR = 0.65, 95%CI = 0.44-0.98).

CONCLUSION

RASSF1A, RARβ, and CDH1 promoter hypermethylation might significantly increase the risk of oral cancer.

DNA Methylation Analysis of the SHOX2 and RASSF1A Panel in Bronchoalveolar Lavage Fluid for Lung Cancer Diagnosis

Introduction: Currently the majority of lung cancer patients are diagnosed as advanced diseases for no sensitive and specific biomarkers exist, noninvasive biomarkers with high sensitivity and specificity are urgently needed in lung cancer diagnosis. Bronchoscopy is a standard procedure of the diagnostic work-up of patients with suspected lung cancer despite of the limited diagnostic accuracy. Besides, epigenetic changes through DNA methylation play an important role in tumorigenesis. Thus, we examined the aberrant methylation of the SHOX2 and RASSF1A in bronchoalveolar lavage fluid (BALF) in comparing with conventional cytology examination and serum CEA in order to evaluate the new diagnostic method.

Patients and Methods: BALF and serum samples were collected from 322 patients at the time of diagnosis, 284 of them were pathologically confirmed lung cancer, 35 were benign lung diseases and 3 were malignancies in other systems. For all of the 322 patients, the methylation status of the SHOX2 and RASSF1A gene were detected by a new RT-PCR platform and then confirmed by sanger sequencing. Serum CEA were detected using electrochemiluminescence immunoassay.

Results: Profiling data showed the consistency of RT-PCR and sanger sequencing in detecting the methylation of the SHOX2 and RASSF1A. Besides, the combination of SHOX2 and RASSF1A methylation in BALF yielded a diagnostic sensitivity of 81.0% and specificity of 97.4%. When compared with established cytology examination (sensitivity: 68.3%, specificity: 97.4%) and serum biomarker carcinoembryonic antigen (CEA) (sensitivity: 30.6%, specificity: 100.0%), the SHOX2 and RASSF1A methylation panel showed the highest diagnostic efficiency. Notably, the combination of cytology and the SHOX2 and RASSF1A methylation panel could significantly improve the diagnostic efficacy.

Conclusion: The methylation analysis of the SHOX2 and RASSF1A panel in BALF with RT-PCR achieved a satisfactory sensitivity and specificity in lung cancer diagnosis, especially in an early stage. It could be used as a promising noninvasive biomarker for auxiliary diagnosis of lung cancer.

Meta-analysis of promoter methylation in eight tumor-suppressor genes and its association with the risk of thyroid cancer

Promoter methylation in a number of tumor-suppressor genes (TSGs) can play crucial roles in the development of thyroid carcinogenesis. The focus of the current meta-analysis was to determine the impact of promoter methylation of eight selected candidate TSGs on thyroid cancer and to identify the most important molecules in this carcinogenesis pathway. A comprehensive search was performed using Pub Med, Scopus, and ISI Web of Knowledge databases, and eligible studies were included. The methodological quality of the included studies was evaluated according to the Newcastle Ottawa scale table and pooled odds ratios (ORs); 95% confidence intervals (CIs) were used to estimate the strength of the associations with Stata 12.0 software. Egger's and Begg's tests were applied to detect publication bias, in addition to the "Metatrim" method. A total of 55 articles were selected, and 135 genes with altered promoter methylation were found. Finally, we included eight TSGs that were found in more than four studies (RASSF1, TSHR, PTEN, SLC5A, DAPK, P16, RARβ2, and CDH1). The order of the pooled ORs for these eight TSGs from more to less significant was CDH1 (OR = 6.73), SLC5 (OR = 6.15), RASSF1 (OR = 4.16), PTEN (OR = 3.61), DAPK (OR = 3.51), P16 (OR = 3.31), TSHR (OR = 2.93), and RARβ2 (OR = 1.50). Analyses of publication bias and sensitivity confirmed that there was very little bias. Thus, our findings showed that CDH1 and SCL5A8 genes were associated with the risk of thyroid tumor genesis.

Potential of RASSF1A promoter methylation as biomarker for endometrial cancer: A systematic review and meta-analysis

BACKGROUND

An epigenetic approach to explaining endometrial carcinogenesis necessitates good understanding of Ras association domain family 1 isoform A (RASSF1A) promoter methylation data from primary studies.

AIMS

Differential magnitude of reported associations between RASSF1A promoter methylation and endometrial cancer (EC) prompted a meta-analysis to obtain more precise estimates.

METHODS

Literature search yielded eight included articles. We calculated pooled odds ratios (OR) and 95% confidence intervals and subgrouped the data by race. Sources of heterogeneity were investigated with outlier analysis.

RESULTS

The pooled ORs indicated increased risk, mostly significant. The overall effect (OR 11.46) was reflected in the European outcome (OR 15.07). However, both findings were heterogeneous (I²=57-70%) which when subjected to outlier treatment, erased heterogeneity (I²=0%) and retained significance (OR 9.85-12.66). Significance of these pre- and post-outlier outcomes were pegged at P≤0.0001. Only the Asian pre-outlier (OR 6.85) and heterogeneous (I²=82%) outcome was not significant (P=0.12) but when subjected to outlier treatment, erased heterogeneity (I²=0%) and generated significance (OR 23.74, P≤0.0001).

CONCLUSIONS

Consistent increased risk associations underpinned by significance and robustness render RASSF1A with good biomarker potential for EC.

The Indirect Efficacy Comparison of DNA Methylation in Sputum for Early Screening and Auxiliary Detection of Lung Cancer: A Meta-Analysis

Background: DNA methylation in sputum has been an attractive candidate biomarker for the non-invasive screening and detection of lung cancer. Materials and Methods: Databases including PubMed, Ovid, Cochrane library, Web of Science databases, Chinese Biological Medicine (CBM), Chinese National Knowledge Infrastructure (CNKI), Wanfang, Vip Databases and Google Scholar were searched to collect the diagnostic trials on aberrant DNA methylation in the screening and detection of lung cancer published until 1 December 2016. Indirect comparison meta-analysis was used to evaluate the diagnostic value of the included candidate genes. Results: The systematic literature search yielded a total of 33 studies including a total of 4801 subjects (2238 patients with lung cancer and 2563 controls) and covering 32 genes. We identified that methylated genes in sputum samples for the early screening and auxiliary detection of lung cancer yielded an overall sensitivity of 0.46 (0.41–0.50) and specificity of 0.83 (0.80–0.86). Combined indirect comparisons identified the superior gene of SOX17 (sensitivity: 0.84, specificity: 0.88), CDO1 (sensitivity: 0.78, specificity: 0.67), ZFP42 (sensitivity: 0.87, specificity: 0.63) and TAC1 (sensitivity: 0.86, specificity: 0.75). Conclusions: The present meta-analysis demonstrates that methylated SOX17, CDO1, ZFP42, TAC1, FAM19A4, FHIT, MGMT, p16, and RASSF1A are potential superior biomarkers for the screening and auxiliary detection of lung cancer.