Aberrant hypermethylation of RASSF2 in tumors and peripheral blood DNA as a biomarker for malignant progression and poor prognosis of esophageal squamous cell carcinoma

Circulating cell-free DNA-based methylation pattern in plasma for early diagnosis of esophagus cancer

With the increased awareness of early tumor detection, the importance of detecting and diagnosing esophageal cancer in its early stages has been underscored. Studies have consistently demonstrated the crucial role of methylation levels in circulating cell-free DNA (cfDNA) in identifying and diagnosing early-stage cancer. cfDNA methylation pertains to the methylation state within the genomic scope of cfDNA and is strongly associated with cancer development and progression. Several research teams have delved into the potential application of cfDNA methylation in identifying early-stage esophageal cancer and have achieved promising outcomes. Recent research supports the high sensitivity and specificity of cfDNA methylation in early esophageal cancer diagnosis, providing a more accurate and efficient approach for early detection and improved clinical management. Accordingly, this review aims to present an overview of methylation-based cfDNA research with a focus on the latest developments in the early detection of esophageal cancer. Additionally, this review summarizes advanced analytical technologies for cfDNA methylation that have significantly benefited from recent advancements in separation and detection techniques, such as methylated DNA immunoprecipitation sequencing (MeDIP-seq). Recent findings suggest that biomarkers based on cfDNA methylation may soon find successful applications in the early detection of esophageal cancer. However, large-scale prospective clinical trials are required to identify the potential of these biomarkers.

Association Between RASSF2 Methylation and Gastric Cancer: A PRISMA-Compliant Systematic Review and Meta-Analysis

RASSF2 is a tumor suppressor gene closely related to gastric cancer. This meta-analysis was designed to assess the quality in the previous studies and establish the value of RASSF2 methylation in the prediction and prognosis of gastric cancer. The eligible literatures with publication deadline of May 3, 2019 were collected from PubMed, EMBASE, CNKI, Wanfang, and CNVIP databases. The correlation between RASSF2 methylation level and gastric cancer was estimated by odds ratio and 95% confidence interval (OR and 95% CI) values. A total of eight articles were included in the study. A total of 517 gastric cancer tissue samples and 517 adjacent nontumor tissue samples were included. The results of the analysis showed that RASSF2 had a significantly higher level of methylation in gastric cancer (OR = 17.56, 95% CI = 7.11-43.35, p-value = 0.009). Meanwhile, we tested whether there was association of RASSF2 methylation with tumor metastasis, and we also analyzed whether there was a gender difference in RASSF2 methylation. However, our results showed no statistical significance of the two aforementioned tests (p > 0.1). Our study suggested that RASSF2 methylation could predict the risk of gastric cancer. However, it might not be feasible for the prediction of tumor metastasis.

Genomic and Epigenomic Aberrations in Esophageal Squamous Cell Carcinoma and Implications for Patients

Esophageal squamous cell carcinoma (ESCC) is a common malignancy without effective therapy. The exomes of more than 600 ESCCs have been sequenced in the past 4 years, and numerous key aberrations have been identified. Recently, researchers reported both inter- and intratumor heterogeneity. Although these are interesting observations, their clinical implications are unclear due to the limited number of samples profiled. Epigenomic alterations, such as changes in DNA methylation, histone acetylation, and RNA editing, also have been observed in ESCCs. However, it is not clear what proportion of ESCC cells carry these epigenomic aberrations or how they contribute to tumor development. We review the genomic and epigenomic characteristics of ESCCs, with a focus on emerging themes. We discuss their clinical implications and future research directions.

FOXF2 promoter methylation is associated with prognosis in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma is a commonly malignant tumor of digestive tract with poor prognosis. Previous studies suggested that forkhead box F2 ( FOXF2) could be a candidate gene for assessing and predicting the prognosis of human cancers. However, the relationship between FOXF2 promoter methylation and the prognosis of esophageal squamous cell carcinoma remained unclear. Formalin-fixed, paraffin-embedded esophageal squamous cell carcinoma tissues of 135 esophageal squamous cell carcinoma patients were detected for FOXF2 promoter methylation status by methylation-specific polymerase chain reaction approach. DNA methylation results were evaluated with regard to clinicopathological features and overall survival. Our study confirmed that FOXF2 promoter hypermethylation could independently predict a poorer overall survival of esophageal squamous cell carcinoma patients ( p = 0.002), which was consistent with the data mining results of the data from 82 esophageal squamous cell carcinoma patients in The Cancer Genome Atlas datasets ( p = 0.036). In addition, no correlation was found between FOXF2 promoter methylation and other clinic pathological parameters (age, gender, differentiation, lymph node metastasis, stage, cutting edge, vascular invasion, smoking behavior, and drinking history). In conclusion, FOXF2 methylation might be a useful prognostic biomarker for esophageal squamous cell carcinoma patients.

The mechanisms of radioresistance in esophageal squamous cell carcinoma and current strategies in radiosensitivity

Esophageal cancer is the eighth most common cancer and the sixth leading cause of cancer-related death worldwide. Surgery is the primary form of treatment, but the survival is poor, especially for patients with locally advanced esophageal cancer. Radiotherapy has been a critical treatment option that may be combined with chemotherapy in patients with unresectable esophageal cancer. However, resistance to chemoradiotherapy might result in treatment failures and cancer relapse. This review will mainly focus on the possible cellular mechanisms and tumor-associated microenvironmental (TAM) factors that result in radioresistance in patients with esophageal cancer. In addition, current strategies to increase radiosensitivity, including targeted therapy and the use of radiosensitive biomarkers in clinical treatment, are discussed in this review.

Proteomics Analysis Reveals Novel RASSF2 Interaction Partners

RASSF2 is a tumor suppressor that shares homology with other Ras-association domain (RASSF) family members. It is a powerful pro-apoptotic K-Ras effector that is frequently inactivated in many human tumors. The exact mechanism by which RASSF2 functions is not clearly defined, but it likely acts as a scaffolding protein, modulating the activity of other pro-apoptotic effectors, thereby regulating and integrating tumor suppressor pathways. However, only a limited number of RASSF2 interacting partners have been identified to date. We used a proteomics based approach to identify additional RASSF2 interactions, and thereby gain a better insight into the mechanism of action of RASSF2. We identified several proteins, including C1QBP, Vimentin, Protein phosphatase 1G and Ribonuclease inhibitor that function in diverse biological processes, including protein post-translational modifications, epithelial-mesenchymal transition, cell migration and redox homeostasis, which have not previously been reported to interact with RASSF2. We independently validated two of these novel interactions, C1QBP and Vimentin and found that the interaction with C1QBP was enhanced by K-Ras whereas, interestingly, the Vimentin interaction was reduced by K-Ras. Additionally, RASSF2/K-Ras regulated the acetylation of Vimentin. Our data thus reveal novel mechanisms by which RASSF2 may exert its functions, several of which may be Ras-regulated.