RASSF1A gene promoter methylation in esophageal cancer specimens

DNA methylation markers in esophageal cancer

Background

Esophageal cancer (EC) is a prevalent malignancy characterized by a low 5-year survival rate, primarily attributed to delayed diagnosis and limited therapeutic options. Currently, early detection of EC heavily relies on endoscopy and pathological examination, which pose challenges due to their invasiveness and high costs, leading to low patient compliance. The detection of DNA methylation offers a non-endoscopic, cost-effective, and secure approach that holds promising prospects for early EC detection.

Methods

To identify improved methylation markers for early EC detection, we conducted a comprehensive review of relevant literature, summarized the performance of DNA methylation markers based on different input samples and analytical methods in EC early detection and screening.

Findings

This review reveals that blood cell free DNA methylation-based method is an effective non-invasive method for early detection of EC, although there is still a need to improve its sensitivity and specificity. Another highly sensitive and specific non-endoscopic approach for early detection of EC is the esophageal exfoliated cells based-DNA methylation analysis. However, while there are substantial studies in esophageal adenocarcinoma, further more validation is required in esophageal squamous cell carcinoma.

Conclusion

In conclusion, DNA methylation detection holds significant potential as an early detection and screening technology for EC.

The detective, prognostic, and predictive value of DNA methylation in human esophageal squamous cell carcinoma

Esophageal cancer is one of the most common malignancies in the world. Squamous cell carcinoma accounts for approximately 90 % of esophageal cancer cases. Genetic and epigenetic changes have been found to accumulate during the development of various cancers, including esophageal squamous carcinoma (ESCC). Tobacco smoking and alcohol consumption are two major risk factors for ESCC, and both tobacco and alcohol were found to induce methylation changes in ESCC. Growing evidence demonstrates that aberrant epigenetic changes play important roles in the multiple-step processes of carcinogenesis and tumor progression. DNA methylation may occur in the key components of cancer-related signaling pathways. Aberrant DNA methylation affects genes involved in cell cycle, DNA damage repair, Wnt, TGF-β, and NF-κB signaling pathways, including P16, MGMT, SFRP2, DACH1, and ZNF382. Certain genes methylated in precursor lesions of the esophagus demonstrate that DNA methylation may serve as esophageal cancer early detection marker, such as methylation of HIN1, TFPI-2, DACH1, and SOX17. CHFR methylation is a late stage event in ESCC and is a sensitive marker for taxanes in human ESCC. FHIT methylation is associated with poor prognosis in ESCC. Aberrant DNA methylation changes may serve as diagnostic, prognostic, and chemo-sensitive markers. Characterization of the DNA methylome in ESCC will help to better understand its mechanisms and develop improved therapies.

Association between Ras association domain family 1A promoter methylation and esophageal squamous cell carcinoma: a meta-analysis

RASSF1A has been reported to be a candidate tumor suppressor in esophageal squamous cell carcinoma (ESCC). However, the association between RASSF1A promoter methylation and ESCC remains unclear. Eligible studies were identified through searching PubMed, Medline, Web of Science, and the China National Knowledge Infrastucture database. Studies were pooled and odds ratios (ORs) with corresponding confidence intervals (CIs) were calculated. Funnel plots were also performed to evaluate publication bias. Twelve studies involving 859 cases and 675 controls were included in this meta-analysis. A significant association was observed between RASSF1A methylation and ESCC overall (OR = 11.7, 95% CI: 6.59-20.9, z=8.36, P<0.00001). Subgroup analysis showed that the OR for heterogeneous tissues was 5.35 (95% CI = 2.95-9.71) while for autologous tissues it was 16.0 (8.31-30.96). For patient sample size, the OR for the <50 subgroup was 9.92 (95% CI = 2.88-34.2) and for the 50 case group was 13.1 (95% CI = 6.59-25.91). The OR for a relationship between RASSF1A methylation and TNM stages was 0.27 (95% CI=0.10-0.77), whereas there were no significant differences in RASSF1A methylation in relation to gender and differentiation among ESCC cases. This meta-analysis suggests a significant association between RASSF1A methylation and ESCC.

Polymorphism of A133S and promoter hypermethylation in Ras association domain family 1A gene (RASSF1A) is associated with risk of esophageal and gastric cardia cancers in Chinese population from high incidence area in northern China

Background

The role of tumor suppressor gene RASSF1A in the esophageal and gastric cardia carcinogenesis is still inconclusive. In this study, the polymorphism, promoter methylation and gene expression of RASSF1A were characterized in esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA).

Methods

We firstly analyzed the prevalence of RASSF1A A133S in a total of 228 cancer patients with ESCC (n=112) and GCA (n=116) and 235 normal controls by polymerase chain reaction (PCR) and restriction enzyme-digestion assay. Then, the promoter methylation status of the RASSF1A in ESCC (n=143), GCA (n=92) and corresponding adjacent normal tissues were further investigated using methylation-specific PCR (MSP) approach. Finally, the RASSF1A protein expression were determined in ESCC (n=27), GCA (n=24) and the matched adjacent normal tissues by immunohistochemical method.

Results

The frequency of 133Ala/Se and Ser/Ser genotype was significantly higher in GCA patients than in normal controls (19.0% vs. 10.2%, P=0.02). Compared with Ala/Ala genotype, Ala/Se and Ser/Ser genotype significantly increased susceptibility to GCA (OR=2.06, 95% CI=1.09–3.97). However, this polymorphism had no association with ESCC (P=0.69). The promoter methylation of RASSF1A gene was significantly increased the risk to both ESCC (OR=5.90, 95% CI=2.78–12.52) and GCA (OR=7.50, 95% CI= 2.78–20.23). Promoter methylation of RASSF1A gene in ESCC was also associated with age and cancer cell differentiation (for age: OR=3.11, 95% CI=1.10–8.73; for differentiation: OR=0.29, 95% CI=0.12–0.69). RASSF1A positive expression was significantly decreased the risk of GCA (OR=0.16, 95% CI=0.03–0.83). In contrast, there was no statistical significance between RASSF1A positive expression and ESCC. The expression of RASSF1A protein trend to be positively related with older GCA patients (OR=16.20, 95% CI=1.57–167.74).

Conclusions

The present findings suggest that alterations of RASSF1A may play an important role in gastric cardia carcinogenesis in terms of polymorphism, promoter hypermethylation and protein expression. Whereas, RASSF1A hypermethylation may probably also be involved in esophageal squamous cell carcinogenesis.

Hypermethylation-modulated downregulation of RASSF1A expression is associated with the progression of esophageal cancer

BACKGROUND AND AIMS

Chromosome 3p21 is an important locus harboring critical tumor suppressor genes (TSGs) implicated in the pathogenesis of multiple tumors including esophageal carcinoma (EC). Aberrant promoter methylation is a fundamental mechanism of inactivation of TSGs in cancer. RASSF1A, a candidate tumor suppressor gene, recently cloned from the lung tumor locus at 3p21.3, is frequently inactivated by hypermethylation of its promoter region in a number of malignancies. We undertook this study to investigate the methylation status of RASSF1A and its significance in esophageal squamous cell carcinoma (ESCC).

METHODS

Real-time RT-PCR and real-time methylation-specific PCR (real-time MSP) were used to detect RASSF1A expression and the methylation status of the RASSF1A promoter, respectively, in 124 primary ESCC tissues.

RESULTS

Hypermethylation, partial methylation and unmethylation of the promoter region of RASSF1A were detected in 56 (45.2%), 23 (18.6%) and 45 (36.2%) of 124 ESCC samples, respectively. Unmethylation of the promoter region of RASSF1A was detected in 119 (96%) of the 124 corresponding noncancerous tissues. Five (4.0%) of 124 noncancerous tissues showed partial methylation. The presence of hypermethylation was statistically associated with loss of RASSF1A mRNA expression in primary ESCC (p <0.05). There were statistically significant correlations between the presence of hypermethylation and regional lymph node involvement (p=0.000), histological differentiation (p=0.009) and tumor stage (p=0.000).

CONCLUSIONS

Our results suggest that RASSF1A may be one of the ESCC-related TSGs located at 3p21, and hypermethylation of the CpG island promoter of the RASSF1A is associated with the progression of ESCC.

DNA methylation in thoracic neoplasms

Thoracic neoplasms, which include lung cancers, esophageal carcinoma, and thymic epithelial tumors, are the leading causes of tumor-related death and a major health concern worldwide. The development of neoplasms is a multistep process involving both genetic and epigenetic alterations. A growing body of research provides evidence that aberrant DNA methylation, including DNA hypermethylation in promoter regions, global DNA hypomethylation and the overexpression of DNA methyltransferases, plays an important role in tumorigenesis. In this review, we summarize published observations of methylation pattern disruptions in thoracic tumors, and discuss how these abnormalities contribute to the development of cancers. We review recent findings showing that suppressing the activity of the DNA methylating enzymes DNMTs can have potent anti-cancer effects, and discuss the possibility of developing novel therapies for thoracic tumors based on DNMT inhibition.

Prognostic significance of RASSF1A expression and methylation status in esophageal squamous cell carcinoma

AIM: To investigate the expression and methylation status of the RASSF1A gene in esophageal squamous cell carcinoma (ESCC) and to analyze their prognostic significance.

METHODS: The mRNA expression and DNA methylation of the promoter region of the RASSF1A gene in normal esophageal tissue samples and ESCC tissue samples taken from 49 ESCC patients were detected by real-time RT-PCR and real-time methylation-specific PCR (qMSP), respectively.

RESULTS: RASSF1A mRNA expression was down-regulated in 53.06% (26/49) of ESCC tissue samples. The level of RASSF1A mRNA expression in ESCC was significantly lower than that in adjacent normal tissue (P < 0.05). Down-regulation of RASSF1A mRNA expression was correlated with TNM stage, lymph node metastasis and poor prognosis in ESCC patients (all P < 0.05). Hypermethylation of the RASSF1A gene promoter region was detected in 77.60% (38/49) of ESCC patients. RASSF1A gene promoter hypermethylation was correlated with TNM stage, lymph node metastasis and poor prognosis in ESCC patients (all P < 0.05).

CONCLUSION: RASSF1A gene promoter hypermethylation is a very common molecular event in ESCC and may be responsible for the down-regulation of RASSF1A mRNA expression. Down-regulation of RASSF1A mRNA expression and hypermethylation of RASSF1A gene promoter region were significantly correlated with lymph node metastasis, TNM stage and poor prognosis in ESCC patients.

Aberrant CpG island hypermethylation of RASSF1A in gastric cardia adenocarcinoma

Ras-association domain family 1A (RASSF1A) gene, a candidate tumor suppressor gene, is inactivated in several human tumors, usually by hypermethylation of its promoter region. RASSF1A induces cell cycle arrest through inhibition of cyclin D1 accumulation. In this work, the promoter methylation status of the RASSF1A in 92 gastric cardia adenocarcinoma (GCA) and corresponding normal tissues were investigated using Methylation-specific PCR (MSP) approach, immunohistochemistry method and RT-PCR were used respectively to examine the protein expression and mRNA expression of RASSF1A in tumors and corresponding normal tissues. Cyclin D1 expression was examined by immunohistochemistry. RASSF1A was methylated in 54/92 (58.7%) tumor specimens, which was significantly higher than that in corresponding normal tissues (p <.001). Methylation frequencies of stage III and IV tumor tissues were significantly higher than that in stage I and II tumor tissues (p <.05). By immunostaining, 43/92 (46.7%) tumor tissues demonstrated heterogeneous, positive immunostaining of tumor tissues was significantly reduced with comparison to matched normal tissues (p <.001). mRNA expressions of RASSF1A in GCA tumor tissues were reduced significantly with comparison to the corresponding normal tissues (OD value: 0.2376 +/- 0.2315 vs 0.6874 +/- 0.2668, p <.001). RASSF1A mRNA expression in methylation group of GCA was significantly different from that in unmethylation group (p <.001). Cyclin D1 hyper-expression was found in 72/92 (78.3%) cases and correlated with RASSF1A methylation (p <.05). Our data suggested that epigenetic silencing of RASSF1A gene expression by promoter hypermethylation may play an important role in GCA.

Aberrant promoter CpG island hypermethylation of the adenomatosis polyposis coli gene can serve as a good prognostic factor by affecting lymph node metastasis in squamous cell carcinoma of the esophagus

There has been no clear evidence demonstrating whether DNA hypermethylation can affect the prognosis of esophageal cancer. We collected tissue from 50 cases of squamous cell carcinoma of the esophagus and tested them for DNA hypermethylation using methylation-specific polymerase chain reaction. CpG island hypermethylations were observed in 10% for p16, 34% for RARbetaP2, 46% for adenomatosis polyposis coli (APC), 14% for RASSF1A, 84% for FHIT, and 8% for hMLH1. APC promoter hypermethylation was frequently found in patients without lymph node metastasis compared with those with lymph node metastasis (62.5% : 30.8%, P = 0.025). The number of metastatic lymph nodes were lower in patients with APC promoter hypermethylation (0.87 +/- 0.30 : 3.07 +/- 0.72, P = 0.008). Excluding operative mortalities and incomplete resections, 42 patients were analyzed for long-term outcome. During the mean follow-up period of 35 months, 17 developed recurrence and 14 died of cancer. Ten patients died of other causes. In univariable analysis, unmethylation of APC (P = 0.0015) and FHIT (P = 0.0044), as well as presence of lymph node metastasis (P = 0.0038), were risk factors for recurrence. In multivariable analysis, lymph nodes metastasis (P = 0.050) and unmethylation of APC promoter (P = 0.023) remained as significant risk factors. In conclusion, promoter hypermethylation of the APC gene is related to a lower number of metastatic lymph nodes and to superior prognosis in terms of recurrence, which suggests it might be involved in the process of lymph node metastasis in esophageal cancer.

Reduced expression of RASSF1A in esophageal and nasopharyngeal carcinomas significantly correlates with tumor stage

Reduced expression or loss of tumor suppressor genes play a key role in many cancers. In this study, we investigated the role of RASSF1A in the pathogenesis of esophageal squamous cell carcinoma (ESCC) and nasopharyngeal carcinoma (NPC). We detected the down-regulated expression of both RASSF1A transcripts and protein in tumor tissues using RT-PCR and tissue microarray immunohistochemical staining analyses. Down-regulated expression of RASSF1A showed a significant association with WHO grade, tumor status, and lymph node metastasis, showing its possible utility as a biomarker for clinical specimens.

DNA Methylation of Multiple Genes in Vestibular Schwannoma

HYPOTHESIS

The purpose of this study was to examine the DNA methylation profile of several genes in a series of vestibular schwannomas, and to analyze its relationship with clinical and radiological features.

BACKGROUND

Aberrant methylation of promoter regions is a major mechanism for silencing of tumor suppressor genes in several tumors. There is limited information about methylation status in vestibular schwannoma, with no clinical or radiological implications described to date.

METHODS

The methylation status of 16 tumor-related genes including RASSF1A, RAR-B, VHL, PTEN, HMLH1, RB1, TP16, CASP8, ER, TIMP3, MGMT, DAPK, TP73, GSTP1, TP14, and THBS1 was examined in a series of 22 vestibular schwannomas.The bisulfite modification of genomic DNA was performed. Clinical and radiological features were compared with the methylation results.

RESULTS

Methylation values from 9% to 27% were found in 12 of 16 genes tested, including RASSF1A, VHL, PTEN, TP16, CASP8, TIMP3, MGMT, DAPK, THBS1, HMLH1, TP73, and GSTP1. A significant association was found between CASP8 and RASSF1A methylation. Methylation of CASP8 was associated with the patient's age and the tumor size. Methylation of TP73 was associated with hearing loss. RASSF1A methylation was inversely correlated with the clinical growth index.

CONCLUSION

Aberrant methylation of tumor-related genes may play a role in the development of vestibular schwannomas. Our results may provide useful clues to the development of prognostic assays for these tumors.

Role of multiple genes methylation in pancreatic carcinogenesis

AIM: To determine methylation status of RASSF1A, p16, SOCS-1 and hMLH1 genes and explore the roles of their concurrent methylation in the carcinogenesis of pancreatic cancer.

METHODS: DNA in pancreatic cancer and cancer-adjacent tissues was extracted by saturated NaCl method. The methylation status of these genes was detected by methylation-specific polymerase chain reaction (MSP).

RESULTS: The methylation rates of RASSF1A, p16, SOCS-1 and hMLH1 were 36.4%, 13.6%, 13.6% and 4.5% in cancer-adjacent tissues and 59.1%, 40.9%, 31.8% and 18.2% in pancreatic cancer, respectively. The methylation rate of p16 in pancreatic cancer was significantly higher than that in the cancer-adjacent tissues (χ² = 4.13, P < 0.05). Two or more genes concurrent methylation was found in 45.5% pancreatic cancer, significantly higher than that in the cancer-adjacent tissues (9.1%, χ² = 7.33, P < 0.01). No methylation of these genes was found in 31.8% pancreatic cancer.

CONCLUSION: Multiple genes concurrent methylation is an early event in some cases of pancreatic cancer, in which it plays an important role.