Research progress of biomarkers in diagnosis and therapy of colorectal cancer / 国际生物医学工程杂志

Colorectal cancer (CRC) is one of the most common human malignant diseases, the cumulative result of genetic and epigenetic mutations, and its mortality rate is second only to that of lung cancer. Most patients with CRC have developed to middle to advanced stage when symptoms appear, and the treatment effects of surgery and chemotherapy are usually not satisfactory. With the emergence of targeted drugs in recent years, individualized treatment of colorectal cancer has gradually become a trend. With the development of colorectal cancer research, more and more molecular markers of colorectal cancer have been continuously discovered, and its impact on tumorigenesis, development and treatment has gradually received more attention. The application of molecular markers in the screening of colorectal cancer can help the early detection and diagnosis. Detection of molecular markers before individualized treatment can optimize the treatment plan and prompt the patient's prognosis. In this paper, the most recent findings of molecular markers with promising clinical application were summarized, in order to provide reference for the early diagnosis and treatment of colorectal cancer.

CpG Island Methylator Phenotype and Methylation of Wnt Pathway Genes Together Predict Survival in Patients with Colorectal Cancer

PURPOSE: Dysregulation of the Wnt pathway is a crucial step in the tumorigenesis of colorectal cancer (CRC). This study aimed to determine whether DNA methylation of Wnt pathway genes helps predict treatment response and survival in patients with metastatic or recurrent CRC. MATERIALS AND METHODS: We retrospectively collected primary tumor tissues from 194 patients with metastatic or recurrent CRC. Pyrosequencing was used to examine the methylation of 10 CpG island loci in DNA extracted from formalin-fixed paraffin-embedded specimens. To elucidate the predictive role of DNA methylation markers, Kaplan-Meier survival estimation and Cox regression were performed for progression-free survival and overall survival (OS). RESULTS: The methylation frequencies of the 10 genes analyzed (p16, p14, MINT1, MINT2, MINT31, hMLH1, DKK3, WNT5A, AXIN2, and TFAP2E) were 47.9%, 10.8%, 21.1%, 16.0%, 20.6%, 0.5%, 53.1%, 32.0%, 2.6%, and 2.1%, respectively. We divided patients into three groups based on the number of methylated genes (group 1, no methylation n=38; group 2, 1–2 methylations n=92; group 3, 3 or more methylations n=64). Among patients treated with palliative chemotherapy (n=167), median OSs of groups 1, 2, and 3 were 39.1, 39.7, and 29.1 months, respectively (log rank p=0.013). After adjustment, number of methylations was identified as an independent poor prognostic factor (0–2 methylated vs. ≥3 methylated: hazard ratio, 1.72; 95% confidence interval, 1.16–2.56, p=0.007). CONCLUSION: This study suggests that methylation of Wnt pathway genes, in addition to known CpG island methylator phenotype markers, may help predict treatment outcome and survival in patients with CRC.

A Study on CpG Island Methylator Phenotype involving Tumor Suppressor Genes on Chromosome 3p in Gastric Cancer / 胃肠病学

Background:CpG island methylator phenotype(CIMP)involving tumor suppressor gene( TSG)on short arm of chromosome 3(chromosome 3p)has been found in various types of cancers. However,its correlation with gastric cancer has not been clarified. Aims:To study the clinical significance of CIMP involving TSG on chromosome 3p in gastric cancer. Methods:Methylation specific PCR(MSP)was used to examine methylation profiles for hOGG1,VHL,RAR-B, hMLH1,SEMA3B,RASSF1A,BLU and FHIT harbored in chromosome 3p in 100 gastric cancer and paired paracancerous tissues. High CIMP( CIMP-H)was referred for those samples having four or more synchronously methylated genes. Relationship between CIMP-H and clinicopathological characteristics in gastric cancer was analyzed. Results:Positive methylation rates of VHL(P = 0. 030),hMLH1(P 0. 05). Conclusions:CIMP on chromosome 3p may occur in early stage of oncogenesis of gastric cancer,and influencing tumor differentiation and lymph node metastasis.

The Role of the CpG Island Methylator Phenotype on Survival Outcome in Colon Cancer

BACKGROUND/AIMS: CpG island methylator phenotype (CIMP)- high colorectal cancers (CRCs) have distinct clinicopathological features from their CIMP-low/negative CRC counterparts. However, controversy exists regarding the prognosis of CRC according to the CIMP status. Therefore, this study examined the prognosis of Korean patients with colon cancer according to the CIMP status. METHODS: Among a previous cohort population with CRC, a total of 154 patients with colon cancer who had available tissue for DNA extraction were included in the study. CIMP-high was defined as 3/5 methylated markers using the five-marker panel (CACNA1G, IGF2, NEUROG1, RUNX3, and SOCS1). RESULTS: CIMP-high and CIMP-low/negative cancers were observed in 27 patients (17.5%) and 127 patients (82.5%), respectively. Multivariate analysis adjusting for age, gender, tumor location, tumor stage and CIMP and microsatellite instability (MSI) statuses indicated that CIMP-high colon cancers were associated with a significant increase in colon cancer-specific mortality (hazard ratio [HR], 3.23; 95% confidence interval [CI], 1.20 to 8.69; p=0.02). In microsatellite stable cancers, CIMP-high cancer had a poor survival outcome compared to CIMP-low/negative cancer (HR, 2.91; 95% CI, 1.02 to 8.27; p=0.04). CONCLUSIONS: Regardless of the MSI status, CIMP-high cancers had poor survival outcomes in Korean patients.

The Role of the CpG Island Methylator Phenotype on Survival Outcome in Colon Cancer

BACKGROUND/AIMS: CpG island methylator phenotype (CIMP)- high colorectal cancers (CRCs) have distinct clinicopathological features from their CIMP-low/negative CRC counterparts. However, controversy exists regarding the prognosis of CRC according to the CIMP status. Therefore, this study examined the prognosis of Korean patients with colon cancer according to the CIMP status. METHODS: Among a previous cohort population with CRC, a total of 154 patients with colon cancer who had available tissue for DNA extraction were included in the study. CIMP-high was defined as 3/5 methylated markers using the five-marker panel (CACNA1G, IGF2, NEUROG1, RUNX3, and SOCS1). RESULTS: CIMP-high and CIMP-low/negative cancers were observed in 27 patients (17.5%) and 127 patients (82.5%), respectively. Multivariate analysis adjusting for age, gender, tumor location, tumor stage and CIMP and microsatellite instability (MSI) statuses indicated that CIMP-high colon cancers were associated with a significant increase in colon cancer-specific mortality (hazard ratio [HR], 3.23; 95% confidence interval [CI], 1.20 to 8.69; p=0.02). In microsatellite stable cancers, CIMP-high cancer had a poor survival outcome compared to CIMP-low/negative cancer (HR, 2.91; 95% CI, 1.02 to 8.27; p=0.04). CONCLUSIONS: Regardless of the MSI status, CIMP-high cancers had poor survival outcomes in Korean patients.

Cancer Epigenetics / 대한소화기학회지

Knowledge regarding molecular events of cancer development has been rapidly accumulated during the last decade. The discovery of tumor suppressor gene-silencing by aberrant promoter CpG island hypermethylation and histone-directed chromatin remodeling has led epigenetics to its recognition as an important alternative mechanism for carcinogenesis. Epigenetics does not involve changes in nucleotide sequences, but it affects on genetic composition in many ways. Cancer cells integratively co-opt genetic and epigenetic mechanisms to acquire different aspects of carcinogenetic phenotypes. Since epigenetic changes can be reversed with relative ease, the research of cancer epigenetics provides great potential for new therapeutic regimens.

Clinicopathologic features of sporadic colorectal cancers with CpG island methylator phenotype / 中华消化杂志

Objective To investigate the clinicopathologic features of sporadic colorectal cancers with CpG island methylator phenotype. Methods The methylation of the promotors of the five genes including p14, hMLH1, p16, MGMT and MINT1 were detected using methylation specific PCR in 71 patients to determine the clinicopathologic characteristics of sporadic colorectal cancers with CpG island methylator phenotype. Results Fifteen out of 71 (21. 1%) patients were positive for the CpG island methylator phenotype. The proportion of the right-sided colonic cancers(40. 0% vs. 12. 5% , P