Death-associated Protein Kinase Methylation Research Articles

Clinicopathological significance of DAPK gene promoter hypermethylation in non-small cell lung cancer: A meta-analysis.

Death-associated protein kinase (DAPK) has a strong function of tumor suppression involving apoptosis regulation, autophagy, and metastasis inhibition. Hypermethylation of CpG islands in DAPK gene promoter region is one of the important ways to inactivate this tumor suppressor gene, which might promote lung carcinogenesis. However, the clinicopathological significance of the DAPK promoter hypermethylation in lung cancer remains unclear. In this study, we performed a meta-analysis trying to estimate the clinicopathological significance of DAPK promoter hypermethylation in non-small cell lung cancer (NSCLC). A detailed literature search for publications relevant to DAPK gene promoter methylation and NSCLC was made in PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, CSTJ, Wanfang databases, and SinoMed (CBM). The random-effects model and fixed-effects model were utilized to pool the relative ratio based on the heterogeneity test in the meta-analysis. A total of 41 studies with 3348 patients were included. The frequency of DAPK methylation was significantly higher in NSCLC than in non-malignant control (odds ratio (OR) = 6.88, 95% confidence interval (CI): 4.17-11.35, P < 0.00001). The pooled results also showed that DAPK gene promoter hypermethylation was significantly associated with poor prognosis for overall survival in patients with NSCLC (hazard ratio: 1.23, 95% CI:1.01-1.52, P = 0.04). Moreover, DAPK gene promoter hypermethylation was significantly associated with squamous cell carcinoma (OR: 1.25, 95% CI: 1.01-1.54, P = 0.04) and smoking behavior (OR: 1.42, 95% CI: 1.04-1.93, P = 0.03) but not with TNM stage, tumor differentiation, age, or gender. DAPK promoter hypermethylation might be a candidate diagnostic and prognostic tumor marker for NSCLC.

Digital Loop-Mediated Isothermal Amplification-Based Absolute Methylation Quantification Revealed Hypermethylated DAPK1 in Cervical Cancer Patients.

The aberrant methylation of many genes has been reported to be associated with various carcinomas. Accurate detection of the methylation level could provide critical insights into the diagnostic analysis of diseases. Here, a sensitive HpaII-edited absolute droplet loop-mediated isothermal amplification (HEADLAMP) method based on methylation-sensitive restriction enzyme (MSRE) HpaII was developed for the digital quantification of DNA methylation. Methylation levels of the death-associated protein kinase 1 (DAPK1) gene that is associated with many cancers were studied using β-actin as an internal reference. DAPK1 (2.5 pM) with 0.01% methylation (250 aM) can be detected with the conventional HpaII-edited LAMP assay. Using HEADLAMP, as low as 1% methylation level can be distinguished with an estimated limit of detection of 5 aM (ca. 3 copies/μL). Moreover, HEADLAMP can detect low levels of methylated DAPK1 in normal L-02 cells, while the conventional assay cannot. Finally, HEADLAMP was applied to the detection of DAPK1 methylation in 20 clinical tissue samples, which revealed hypermethylated DAPK1 in cervical cancer patients. We envisage potential applications of this robust, specific, and sensitive HEADLAMP assay in epigenetic studies and early clinical diagnosis.

Comparative study of death-associated protein kinase promoter methylation between nonsquamous and squamous subtypes of nonsmall cell lung cancer

Background Lung cancer is a leading cause of cancer-related mortality in the world. Nonsmall cell lung cancer (NSCLC) can be classified as nonsquamous cell carcinoma (non-SCC) and squamous cell carcinoma (SCC). NSCLC pathogenesis includes altered methylation patterns in multiple genes. Promotor methylation of death-associated protein kinase (DAPK) has been documented in various tumors. Aim To compare DAPK promoter methylation and clinical characteristics in patients of nonsquamous cell lung cancer with those of SCC. Patients and methods A case–control study was conducted on fresh-frozen tumor samples from 81 patients with primary NSCLC, including 43 non-SCC cases and 38 SCC cases, investigated in the Chest Department, Mansoura University Hospital, in the period from June 2017 to January 2020. A total of 40 patients matched for age and sex with nonmalignant lung lesions served as controls. Patients with age more than 18 years, radiological suggestions of lung cancer, and histologically diagnosed NSCLC were included, whereas patients with malignancies other than NSCLC or unfit for bronchoscopy were excluded. A pathologist histologically examined each lung tumor to define the type and other clinical characteristics of the tumor. DNA was isolated from fresh-frozen tissues, and the detection of DNA methylation was performed using methylation-specific PCR. Results NSCLC case groups included 43 nonsquamous cells and 38 squamous cells, with a mean age of 62.89±5.5 and 64.19±5.87 years, respectively. The control group included 40 patients, with a mean age of 61.37±6.64 years. There were statistically significant differences regarding smoking status (P=0.002) and the clinical characteristics suggestive of lung cancer between both patients with NSCLC and controls, but the differences between SCC and non-SCC were not significant. The results were significantly different between the two groups concerning chest radiograph and computed tomographic finding, where the peripheral mass was significantly higher in non-SCC than SCC (P Conclusion Detection of the aberrant DAPK hypermethylation in tumor DNA from patients with NSCLC may provide an effective means for early auxiliary diagnosis of the malignancy but cannot distinguish between the histopathological types.

Diagnostic significance of DNA methylation of PTEN and DAPK in thyroid tumors.

DNA Methylation of the tumour suppressor gene leading to gene silencing plays an important role in thyroid tumour development. The purpose was to determine the DNA methylation status of phosphatase and tensin homolog (PTEN) and death-associated protein kinase (DAPK) in patients with thyroid nodules and to explore whether they can be used as molecular diagnostic tools to differentiate benign and malignant thyroid nodules. Thyroid tissue and blood samples were obtained from normal healthy individuals (controls) and patients suffering from clinically diagnosed thyroid nodular disease [papillary thyroid carcinoma (PTC), adenoma and nodular goitre]. DNA methylation level, mRNA expression and protein expression of PTEN and DAPK in the thyroid tissues and peripheral blood were detected using methylation-specific PCR, semi-quantitative reverse transcription PCR and Western blot, respectively. Diagnostic sensitivity, specific and accuracy of detection were evaluated between blood and thyroid tissue. There was a significant increase in the level of DNA methylation of PTEN and DAPK in PTC (P<.05) compared with controls and other types of thyroid nodules. Levels of the mRNA of both PTEN and DAPK were lower in PTC in both peripheral blood and tissue samples compared with controls, while there was concomitant decrease of both PTEN and DAPK protein expression in PTC tissues (P<.05). There was no significant difference in diagnostic specificity, sensitivity and accuracy between blood sample and thyroid tissues. Hypermethylated status of both PTEN and DAPK in peripheral blood and tissue samples can be useful biomarkers for clinical diagnosis and, distinguishing of benign and malignant thyroid nodules.

Analysis of Promoter Hypermethylation of DAPK and BAX Apoptotic Genes in Iranian Gastric Cancer Patients Undergoing Chemotherapy

Background: The apoptotic route is mostly damaged in gastric cancer tumor cells. DNA methylation of promoter associated CpG islands inactivates tumor suppressor genes. The objective of the present study was to analyze the hypermethylation of death-associated protein kinase (DAPK) and Bcl-2-associated X protein (BAX) genes in individuals suffering from gastric cancer and undergoing chemotherapy. Methods: Genomic DNA was extracted from blood samples and the tissue fixed in the paraffin of 30 patients and normal individuals. Hypermethylation investigation of DAPK and BAX genes was conducted via methylation specific PCR technique, the outcomes of which were analyzed through electrophoresis and SPSS software version 20. Results: Methylation of both BAX and DAPK genes with a frequency of (28.3%, 21.7%) in blood and (23.3%, 23.3%) in tissue, respectively, had a significant relationship with gastric cancer (P˂0.01). A significant relationship was also observed between the methylation of BAX gene in tissue and tumor type (12, 35.3% and P˂0.01). No relationship was found between methylation and grade, stage, node, age, sex, and other pathologic and clinical data of the patients (P>0.05). There was a significant association between simultaneous methylation of DAPK and BAX genes in tumor and typical tissues with methylation a frequency of 40% and 95.83%, respectively (P˂ 0.01). Conclusion: Methylation of the BAX and DAPK genes can be used as a biomarker in bloodand an approach in the early detection of malignity and illness management. Methylation inhibitors with the potential for drug targeting of DAPK and BAX can further be employed in pharmacotherapy.

Prognostic significance of DAPK promoter methylation in lymphoma: A meta-analysis.

We aimed to characterize the clinical significance of epigenetic loss of death-associated protein kinase (DAPK) gene function through promoter methylation in the development and prognosis of lymphoma. PubMed, Web of Science and ProQuest databases were searched for relevant studies. Twelve studies involving 709 patients with lymphoma were identified. The prognostic value of DAPK methylation was expressed as risk ratio (RR) and its corresponding 95% confidence interval (CI), while the associations between DAPK methylation and the clinical characteristics of patients with lymphoma were expressed as odd ratios (ORs) and their corresponding 95% CIs. Meta-analysis showed that the 5-year survival rate was significantly lower in lymphoma patients with hypermethylated DAPK (RR = 0.85, 95% CI (0.73, 0.98), P = 0.025). Sensitivity analysis demonstrated consistent result. However, no associations were found between DAPK methylation and clinicopathological features of lymphoma, in relation to gender (OR = 1.07, 95% CI (0.72, 1.59), P = 0.751), age (OR = 1.01, 95% CI (0.66, 1.55), P = 0.974), international prognostic index (OR = 1.20, 95% CI (0.63, 2.27), P = 0.575), B symptoms (OR = 0.76, 95% CI (0.38, 1.51), P = 0.452), serum lactate dehydrogenase (OR = 1.13, 95% CI (0.62, 2.05), P = 0.683), and BCL-2 expression (OR = 1.55, 95% CI (0.91, 2.66), P = 0.106). Lymphoma patients with hypermethylated DAPK are at risk for poorer 5-year survival rate. DAPK methylation may serve as a negative prognostic biomarker among lymphoma patients, although it may not be associated with the progression of lymphoma.

Diagnostic potential of methylated DAPK in brushing samples of nasopharyngeal carcinoma.

BackgroundThe death-associated protein kinase (DAPK) gene is an important member of the apoptotic pathway and is inactivated by abnormal methylation in numerous cancers, including nasopharyngeal carcinoma (NPC). However, the diagnostic value of DAPK methylation in brushing samples and tissue samples of NPC remains unclear.MethodsWe conducted a systematic meta-analysis based on 17 studies (including 386 tissue cases, 233 brushing cases, and 296 blood cases).ResultsOur results revealed an association between methylated DAPK and increased risk of NPC in blood, brushing, and tissue samples. In addition, the comparison of the pooled sensitivity, specificity, and area under the curve of methylated DAPK in brushing and tissue samples demonstrated the non-inferior effectiveness of methylated DAPK in brushing samples to monitor the development of NPC.

Identification of DAPK1 Promoter Hypermethylation as a Biomarker for Intra-Epithelial Lesion and Cervical Cancer: A Meta-Analysis of Published Studies, TCGA, and GEO Datasets.

Background: Promoter hypermethylation in death-associated protein kinase 1 (DAPK1) gene has been long linked to cervical neoplasia, but the established results remained controversial. Here, we performed a meta-analysis to assess the associations of DAPK1 promoter hypermethylation with low-grade intra-epithelial lesion (HSIL), high-grade intra-epithelial lesion (HSIL), cervical cancer (CC), and clinicopathological features of CC.Methods: Published studies with qualitative methylation data were initially searched from PubMed, Web of Science, EMBASE, and China National Knowledge Infrastructure databases (up to March 2018). Then, quantitative methylation datasets, retrieved from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, were pooled to validate the results of published studies.Results: In a meta-analysis of 37 published studies, DAPK1 promoter hypermethylation progressively increased the risk of LSIL by 2.41-fold (P = 0.012), HSIL by 7.62-fold (P < 0.001), and CC by 23.17-fold (P < 0.001). Summary receiver operating characteristic curves suggested a potential diagnostic value of DAPK1 promoter hypermethylation in CC, with a large area-under-the-curve of 0.83, a high specificity of 97%, and a moderate sensitivity of 59%. There were significant impacts of DAPK1 promoter hypermethylation on histological type (odds ratio (OR) = 3.53, P < 0.001) and FIGO stage of CC (OR = 2.15, P = 0.003). Then, a pooled analysis of nine TCGA and GEO datasets, covering 13 CPG sites within DAPK1 promoter, identified eight CC-associated sites, six sites with diagnostic values for CC (pooled specificities: 74–90%; pooled sensitivities: 70–81%), nine loci associated with the histological type of CC, and all 13 loci with down-regulated effects on DAPK1 mRNA expression.Conclusion: The meta-analysis suggests that DAPK1 promoter hypermethylation is significantly associated with the disease severity of cervical neoplasia. DAPK1 methylation detection exhibits a promising ability to discriminate CC from cancer-free controls.

The prognostic value of DAPK1 hypermethylation in gliomas: A site-specific analysis

Background and aimsThe gene of death associated protein kinase 1 (DAPK1) has been reported to be methylated in various cancers including gliomas. However, its prognostic value for gliomas is still controversy, and the methylation at specific CpG sites of DAPK1 has not been investigated. The aim of this study was to prognostically evaluate the methylation level of different CpG sites within DAPK1 promoter region in gliomas. MethodsBased on sodium bisulfite treated DNA products, we made use of DNA pyrosequencing method to evaluate overall and site-specific methylation of DAPK1 in 143 gliomas and 26 benign tumors (meningeomas) or normal brain tissues. We both statistically analyzed the association between methylation levels of each CpG site and the clinicopathological characteristics, and estimated the prognosis predictive value of site-specific methylation for glioma patients. ResultsMethylation status of DAPK1 site −1527, −1543, and the overall five sites concerned was higher in gliomas than controlled subjects (p < 0.001). Hypermethylation at site −1527 or together with site −1543 associated with better survival in patients taken postoperative therapies (−1527: p = 0.002; −1527 & −1543: p = 0.023), as well as in patients just underwent radiotherapy after surgery (-1527: p = 0.015; −1527 & −1543: p = 0.030). However, Cox regression analysis indicated the site-specific methylation was not independent contributor for gliomas prognosis. ConclusionAnalysis of DAPK1 gene promoter by quantitative pyrosequencing provided more detailed information of methylation status of CpG sites. DAPK1 methylation level is associated with gliomas clinical features and outcomes. Interestingly, the hypermethylation at site −1527 or together with site −1543 indicated good sensitivity of postoperative therapies, especially radiotherapy. Thus, site specifically analysis of DAPK1 methylation may be a valuable diagnostic and prognostic estimation for gliomas.

Relationship between DAPK methylation and gene inactivation in papillary thyroid carcinoma

To investigate the relationship between the methylation of death-associated protein kinase (DAPK) promoter and gene inactivation in papillary thyroid carcinoma, the technique of methylation-specific polymerase chain reaction (PCR (MSP)) was applied to detect the methylation status of DAPK gene promoter in 70 cases of papillary thyroid carcinoma (study group) and in 50 cases of corresponding adjacent tissues (control group). Immunohistochemical method was used to detect the protein expression; besides, the relationship of DAPK methylation and gene inactivation with pathological factors of papillary thyroid cancer was analyzed. The methylation rate of DAPK was 16% (8/50) in the control group and 71.4% (50/70) in the study group with the difference being statistically significant (χ2 = 19.724, P &lt; 0.01). The methylation of DAPK gene promoter was not associated with age, sex, tumor size, TNM stage, and thyroid capsular infiltration in the study group with papillary thyroid carcinoma ( P &gt; 0.05), but was associated with lymph node metastasis ( P &lt; 0.05). Spearman’s rank correlation analysis showed that the methylation of DAPK promoter was negatively correlated with the expression of DAPK (r = −0.793, P &lt; 0.01). The methylation of CpG island in the promoter region of DAPK gene can lead to gene inactivation and may be involved in the occurrence of papillary thyroid carcinoma.

Death-associated protein kinase promoter methylation correlates with clinicopathological and prognostic features in nonsmall cell lung cancer patients: A cohort study.

The objective was to study the correlation between death-associated protein kinase (DAPK) promoter methylation and the clinicopathological and prognostic features in nonsmall cell lung cancer (NSCLC) patients. A total of 117 NSCLC patients were recruited into our study between December 2012 and December 2014. Methylation-specific polymerase chain reaction was employed to detect the methylation status of DAPK in cancer tissues, peficancerous tissues, and serum samples of 117 NSCLC patients. In addition, serum samples of 115 healthy subjects were analyzed as controls. A literature search of English and Chinese databases, based on predefined criteria, identified published studies closely related to this study. Data were extracted, and meta-analysis was performed using STATA 12.0 software (STATA Corporation, College Station, TX, USA). Our study results showed that DAPK promoter methylation frequency was significantly higher in NSCLC tissues compared to peficancerous normal tissues (58.1% vs. 12.8%, χ2 = 52.45, P < 0.001). When serum samples were compared, DAPK methylation frequency in NSCLC patients was higher than the control group (27.4% vs. 0, χ2 = 37.07, P < 0.001). Our meta-analysis results demonstrated that DAPK methylation frequency was lower in tumor node metastasis (TNM) stage I-II compared to TNM stage III-IV (relative risk [RR] =0.87, 95% confidence interval [CI] =0.76-0.99, P = 0.041). DAPK promoter methylation frequency in NSCLC patients with lymph node metastasis was significantly higher compared to the patients with no metastases (RR = 1.26, 95% CI = 1.04-1.52, P = 0.020). Finally, the 5-year survival rate was lower in NSCLC patient group with high frequency of DAPK methylation, compared to the patient group with unmethylated DAPK (RR = 0.71, 95% CI = 0.56-0.89, P = 0.004). Our results showed that DAPK promoter methylation is tightly correlated with clinicopathological features of NSCLC and is associated with poor prognosis in patients.

Correlation of DAPK1 methylation and the risk of gastrointestinal cancer: A systematic review and meta-analysis.

ObjectiveOne of the critical mechanisms of gastrointestinal cancer pathogenesis is the silencing of death associated protein kinase 1 (DAPK1), which could be caused by aberrant methylation of the promoter. However, the relationship between DAPK1 methylation and the risk of gastrointestinal cancer is still controversial. Hence, we conducted this study to determine the potential correlation.MethodsEligible publications were searched in the Pubmed, Embase, and Cochrane Library through November 2016 according to the inclusion criteria and exclusion criteria. Revman 5.3 and Stata 12.0 software were used to analyze the relevant data regarding the association between the frequency of DAPK1 methylation and gastrointestinal cancer.ResultsA total of 22 studies with 2406 patients were included in this meta analysis. Methylation of DAPK1 was positively related with the risk of gastrointestinal cancer (odds ratio [OR] = 5.35, 95% confidence interval [CI]: 2.76–10.38, P<0.00001, random effects model). The source of heterogeneity was analyzed by sensitivity analysis and subgroup analysis. After omitting one heterogeneous study, the I2 decreased and the OR increased in pooled analysis. Also, the heterogeneity decreased most significantly in the subgroup of studies that had a sample size of less than 60 cases. Then, the correlations between DAPK1 methylation and clinicopathological features of gastrointestinal cancer were assessed. DAPK1 methylation was positively correlated with the lymph node (N) stage (positive vs. negative, OR = 1.45, 95%CI: 1.01–2.06, P = 0.04, fixed effects model) and poor differentiation (OR = 1.55, 95%CI: 1.02–2.35, P = 0.04, fixed effects model) in gastric cancer, and the association was significant among Asian patients. However, among cases of gastrointestinal cancer, the association between DAPK1 methylation and tumor (T) stage, N stage, distant metastasis (M) stage, and cancer differentiation were not statistically significant.ConclusionsDAPK1 methylation is a potential biomarker for the early diagnosis of gastrointestinal cancer. Further analysis of the clinicopathological features indicated that aberrant methylation of DAPK1 is positively associated with the tumorigenesis of gastrointestinal cancer, and metastasis of gastric cancer.

IDENTIFICATION OF FREQUENT PROMOTER METHYLATION OF DEATH-ASSOCIATED PROTEIN KINASE IN LIQUID-BASED PAPANICOLAOUS TEST SAMPLES IN VIETNAMESE POPULATION

Objective: The infection of high-risk human papillomavirus (HPV) genotypes, particularly HPV-16 and HPV-18, is known to cause cervical cancer (CC); however, aberrant DNA methylation of death-associated protein kinase (DAPK), a member of tumor suppressor gene family, are required for cervical tumorigenesis. The aim of our study was to evaluate the hypermethylation frequency of CpG belonged to DAPK promoter, in Vietnamese patients, as well as to study about the association between hypermethylation, and high-risk HPV infection leading to CC.Methods: Methylation-specific-polymerase chain reaction (MSP) was performed to analyze methylation status from 109 liquid-based papanicolaous test samples, collected from local hospital and were identified whether HPV/or non-HPV, high-risk/low-risk HPV infection, then was confirmed by sequencing.Results: In the case of high-risk HPV infection, the frequency of DAPK gene hypermethylation was 66.67% (24 of 36 cases). Meanwhile, low hypermethylation status was found in low-risk and non-HPV infection, counting for 12.0% (3 of 25 cases), 2.1% (1 of 48 cases), respectively. Significant association of DAPK hypermethylation with high-risk, low-risk, and non-HPV infection was observed (p&lt;0.0001). The DAPK hypermethylation increased the possibility to CC in the case of high-risk HPV infected with high incidence: Odds ratio=34.5 (95% confidence interval [CI]=10.15-117.23, p&lt;0.01), relative risk=12.2 (95% CI=4.56-32.42, p&lt;0.01).Conclusion: Based on those data, it suggested that MSP carried out on noninvasive samples will lead to potential method to screening, diagnosis and early diagnosis of cervical carcinoma in Vietnamese population.

Promoter methylation and expression of death-associated protein kinase gene in acute leukemia

To study the clinical implications of death-associated protein kinase (DAPK) promoter methylation and DAPK gene expression in untreated patients with acute leukemia. Methylation-specific PCR and RT-PCR were employed to detect the DAPK gene methylation and mRNA expression in the bone marrow of 60 patients with acute myeloid leukemia (AML), 55 patients with acute lymphocytic leukemia (ALL), and 17 normal subjects. The positivity rate of DAPK methylation was significantly higher in ALL patients (29.1%) than in AML patients group (5%) and normal subjects (0%) (P<0.01). No correlation was found between DAPK gene methylation and the clinical features in ALL patients (P>0.05). DAPK mRNA expression level differed significantly among the 3 groups (P=0.000), and was the highest in normal subjects and the lowest in ALL patients. In ALL patients, the expression level of DAPK mRNA showed a significant inverse correlation with DAPK promoter methylation (P<0.05). The methylation rate of DAPK gene is higher in untreated ALL patients than in AML patients and normal subjects. DAPK gene methylation is not correlated with the clinical features of ALL patients but is probably related with the low gene expression level of DAPK in these patients.

Methylation changes of SIRT1, KLF4, DAPK1 and SPG20 in B-lymphocytes derived from follicular and diffuse large B-cell lymphoma

Diffuse large-B cell lymphomas (DLBCL) and follicular lymphomas (FL) are the most represented subtypes among mature B-cell neoplasms and originate from malignant B lymphocytes. Methylation represents one of the major epigenetic mechanisms of gene regulation. Silent information regulator 1 (SIRT1) is a class III lysine-deacetylase playing several functions and considered to be a context-dependent tumor promoter. We present the quantitative methylation, gene expression and tissue distribution of SIRT1 and some key mediators related to lymphoma pathogenesis in B lymphocytes purified from biopsies of follicular hyperplasias, FL and DLBCL.SIRT1 mRNA levels are higher in FL than follicular hyperplasias and DLBCL. B cell lymphoma 6 (BCL6) positively correlates with SIRT1. SIRT1 promoter shows a methylation decrease in the order: follicular hyperplasia – FL – DLBCL. Kruppel-like factor 4 (KLF4), Death-associated protein kinase 1 (DAPK1) and Spastic Paraplegia 20 (SPG20) methylation increase significantly in FL and DLBCL compared to follicular hyperplasias. Gene expression of DAPK1 and SPG20 inversely correlates with their degree of methylation.Our findings evidence a positive correlation between SIRT1 and BCL6 expression increase in FL. SIRT1 methylation decreases in FL and DLBCL accordingly and this parallels the increase of KLF4, DAPK1 and SPG20 methylation.

Promoter methylation of p16 and DAPK genes in brushing, blood, and tissue samples from patients with nasopharyngeal carcinoma: a systematic meta-analysis

Background: Promoter methylation of tumor suppressor genes (TSGs) p16 and death-associated protein kinase ( DAPK ) has been reported in various carcinomas. However, the correlation between p16 or DAPK promoter methylation and the detection of nasopharyngeal carcinoma (NPC) in different sample types remains unclear. Methods: A systematic literature research was conducted to identify available studies. The pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated and analyzed. Results: Eleven eligible papers on p16 promoter methylation and seven eligible papers on DAPK promoter methylation were included in this analysis. The pooled OR of p16 and DAPK promoter methylation was significantly higher in samples of NPC tissues than in nontumorous (OR =5.49, P 0.1). Conclusions: Our findings suggested that p16 and DAPK promoter methylation may be associated with the carcinogenesis of NPC. Promoter methylation of p16 or DAPK may become a noninvasive biomarker for NPC detection in blood and brushing samples. DAPK or p16 promoter methylation was not correlated with tumor stage. Conducting additional studies is essential in the future to confirm our results.

Methylation ofDAPKandTHBS1genes in esophageal gastric-type columnar metaplasia

To explore methylation of DAPK, THBS1, CDH-1, and p14 genes, and Helicobacter pylori (H. pylori) status in individuals harboring esophageal columnar metaplasia. Distal esophageal mucosal samples obtained by endoscopy and histologically diagnosed as gastric-type (non-specialized) columnar metaplasia, were studied thoroughly. DNA was extracted from paraffin blocks, and methylation status of death-associated protein kinase (DAPK), thrombospondin-1 (THBS1), cadherin-1 (CDH1), and p14 genes, was examined using a methyl-sensitive polymerase chain reaction (MS-PCR) and sodium bisulfite modification protocol. H. pylori cagA status was determined by PCR. In total, 68 subjects (33 females and 35 males), with a mean age of 52 years, were included. H. pylori cagA positive was present in the esophageal gastric-type metaplastic mucosa of 18 individuals. DAPK, THSB1, CDH1, and p14 gene promoters were methylated by MS-PCR in 40 (58.8%), 33 (48.5%), 46 (67.6%), and 23 (33.8%) cases of the 68 esophageal samples. H. pylori status was associated with methylation of DAPK (P = 0.003) and THBS1 (P = 0.019). DNA methylation occurs in cases of gastric-type (non-specialized) columnar metaplasia of the esophagus, and this modification is associated with H. pylori cagA positive infection.

DAPK and P16 Methylation and HPV and EBV Infection in Small Cell Carcinoma of Cervix: A Case Report

Purpose: Small cell carcinoma (SMCC) of the cervix is rare and aggressive tumor, often diagnosed in an advanced stage and their prognosis is generally poor. A case of SMCC showing Human Papillomavirus (HPV) and Epstein barr virus (EBV) infection and Death-associated protein kinase (DAPK) and p16 genes methylation is presented. A 74-year-old woman was diagnosed as having stage IB2 of SMCC. Methods: HPV and EBV infection and DAPK and p16 gene methylation were found using molecular approaches. Results: The sample was positive for HPV and EBV infection and showed DAPK and p16 promoter regions methylated Conclusion: Methylation of DAPK and p16 gene could be used as a molecular marker in cervical cancer.

DAPK promoter methylation status correlates with tumor metastasis and poor prognosis in patients with non-small cell lung cancer

This meta-analysis investigated the correlation between the promoter methylation of death-associated protein kinase (DAPK) and the clinicopathological features in patients with non-small cell lung cancer (NSCLC). Scientific literature databases were exhaustively searched to retrieve published studies relevant to DAPK methylation and NSCLC. Retrieved studies published in English and Chinese languages were screened according to the stringent predefined inclusion and exclusion criteria, and high quality studies were selected for meta-analysis. All statistical analyses were performed utilizing STATA software (Version 12.0, Stata Corporation, College Station, TX, USA). A total of 14 published studies (5 in English and 9 in Chinese) were enrolled in the present meta-analysis, and contained 1238 patients with NSCLC. The results indicated that NSCLC patients with metastatic phenotype were strongly associated with significantly higher methylation rate of DAPK compared to NSCLC patients without metastasis. Additionally, in NSCLC patients carrying tumors with DAPK methylation, the 5-year survival rate was remarkedly lower than NSCLC patients without DAPK methylation. However, we did not find significant correlation between DAPK methylation and histological stage or tumor node metastasis (TNM) stage in NSCLC patients. Our meta-analysis results reveal that DAPK promoter methylation might be associated with tumor metastasis and poor prognosis in NSCLC patients, although no correlation with histological types and TNM stage in NSCLC patients were found.

Aberrant methylation and expression of DAPk1 in human hypopharyngeal squamous cell carcinoma

Conclusion: These findings indicate that in hypopharyngeal squamous cell carcinoma (HSCC), hypermethylation and down-regulation of death-associated protein kinase-1 (DAPk1) are common events, which are associated with a poor prognosis. Objectives: This study aimed to investigate the methylation and expression of DAPk1, a tumor suppressor gene, in HSCC, and explore its clinical significance. Methods: The tumor and adjacent non-tumor tissues were collected from 53 patients with HSCC. The methylation status of DAPk1 was detected by methylation–specific polymerase chain reaction (MSP), and expression of DAPk1 was determined with real-time reverse transcriptase polymerase chain reaction (RT-PCR), immunohistochemistry, and Western blot at mRNA or protein levels. Correlations between the findings and patients’ clinicopathological parameters were further evaluated. Results: The methylation ratio of DAPk1 in tumor tissues (60.38%) was significantly higher than that in the adjacent non-tumor tissues (26.42%) (p = 0.001), while DAPk1 expression in the tumors was down-regulated markedly (real-time RT-PCR, p = 0.002; immunohistochemistry, p = 0.006; Western blot, p < 0.001). DAPk1 methylation was negatively correlated with its mRNA expression (p = 0.002, r = –0.521). Both hypermethylation and down-regulation of DAPk1 were closely related to lymph node metastasis (p = 0.001 and 0.001, respectively), advanced TNM stage (p = 0.009 and 0.019, respectively), and low survival rates (p = 0.031 and 0.045, respectively).