Familial Clustering of Gastric Cancer: A Retrospective Study Based on the Number of First-Degree Relatives

Association between gastric cancer and the family history of gastric cancer: a cross-sectional study using Korean Genome and Epidemiology Study data

OBJECTIVE

The risk of gastric cancer based on a family history of gastric cancer remains unclear. The purpose of this study was to investigate the relationship between gastric cancer and family history of gastric cancer within a large cohort in Korea.

METHODS

In total 211 708 participants were recruited in the Korean Genome and Epidemiology Study during 2001-2013, and divided into a group with a self-reported personal history of gastric cancer ( n  = 930) and a 1:40 matched control group ( n  = 37 200). We examined the family history of gastric cancer in first-degree relatives for cross-sectional analysis. Logistic regression was used to estimate the odds ratios (ORs) of gastric cancer according to family history, using four models that were adjusted for different confounding variables, including the interaction among a family history of gastric cancer.

RESULTS

After matching the two groups for age and sex, the gastric cancer group had a significantly higher proportion of family history in each relative than the controls ( P  < 0.001). In the adjusted model, the ORs [95% confidence interval (CI)] for gastric cancer with a history of an affected father, mother and sibling were 1.80 (1.38-2.34), 1.95 (1.42-2.69) and 2.98 (2.31-3.83), respectively, compared with those in the control group. There was no statistically significant interaction among a family history of gastric cancer in each relative.

CONCLUSION

A history of gastric cancer in siblings, among first-degree relatives, is strongly associated with an increased risk of gastric cancer. Regular follow-up and early treatment are recommended for those with a family history of gastric cancer.

Genetic and Epigenetic Alterations of CDH1 Regulatory Regions in Hereditary and Sporadic Gastric Cancer

E-cadherin is a key player in gastric cancer (GC) and germline alterations of CDH1, its encoding gene, are responsible for Hereditary Diffuse Gastric Cancer (HDGC) syndrome. This study aimed at elucidating the role of genetic variants and DNA methylation of CDH1 promoter and enhancers in the regulation of gene expression. For this purpose, we analyzed genetic variants of the CDH1 gene through Next-Generation Sequencing (NGS) in a series of GC cell lines (NCI-N87, KATO-III, SNU-1, SNU-5, GK2, AKG, KKP) and the corresponding CDH1 expression levels. By bisulfite genomic sequencing, we analyzed the methylation status of CDH1 regulatory regions in 8 GC cell lines, in a series of 13 sporadic GC tissues and in a group of 20 HDGC CDH1-negative patients and 6 healthy controls. The NGS analysis on CDH1 coding and regulatory regions detected genetic alterations in 3 out of 5 GC cell lines lacking functional E-cadherin. CDH1 regulatory regions showed different methylation patterns in patients and controls, GC cell lines and GC tissues, expressing different E-cadherin levels. Our results showed that alterations in terms of genetic variants and DNA methylation patterns of both promoter and enhancers are associated with CDH1 expression levels and have a role in its regulation.

Promising aberrant DNA methylation marker to predict gastric cancer development in individuals with family history and long-term effects of H. pylori eradication on DNA methylation

OBJECTIVE

It remains unknown whether individuals with a family history (FH) of gastric cancer (GC) are associated with aberrant DNA methylation. The aim of this study was to investigate the association between aberrant DNA methylation and FH of GC.

DESIGN

Using quantitative MethyLight assay, MOS, miR124a-3, NKX6-1, EMX1, CDH1, and TWIST1 methylation levels in the noncancerous gastric mucosa was compared between subjects with and without FH based on GC and Helicobacter pylori (Hp) infection. Changes in the methylation levels were evaluated over time after Hp eradication.

RESULTS

In Hp-positive GC patients, MOS (P < 0.001), CDH1 (P < 0.001), and TWIST1 (P = 0.004) methylation were decreased in subjects with FH (n = 64) than in those without FH (n = 58). In Hp-positive controls, MOS methylation was lower in subjects with FH (n = 73) than in those without FH (n = 50) (P = 0.042), while miR124a-3 (P = 0.006), NKX6-1 (P < 0.001), and CDH1 (P < 0.001) methylation were higher in subjects with FH. CDH1 methylation constantly decreased from 2 years in GC patients and 3-4 years in controls after Hp eradication (all P < 0.001). A persistent decrease in methylation over time was not observed in other genes after eradication.

CONCLUSION

The methylation of MOS and CDH1 provided an association between aberrant DNA methylation and gastric carcinogenesis in FH of GC, a useful marker for GC risk in individuals with FH. Furthermore, CDH1 methylation decreased after Hp eradication.

Family-based exome sequencing combined with linkage analyses identifies rare susceptibility variants of MUC4 for gastric cancer

Genome-wide association studies of gastric cancer (GC) cases have revealed common gastric cancer susceptibility loci with low effect size. We investigated rare variants with high effect size via whole-exome sequencing (WES) of subjects with familial clustering of gastric cancer. WES of DNAs from the blood of 19 gastric cancer patients and 36 unaffected family members from 14 families with two or more gastric cancer patients were tested. Linkage analysis combined with association tests were performed using Pedigree Variant Annotation, Analysis, and Search Tool (pVAAST) software. Based on the logarithm of odds (LOD) and permutation-based composite likelihood ratio test (CLRT) from pVAAST, MUC4 was identified as a predisposing gene (LOD P-value = 1.9×10-5; permutation-based P-value of CLRT ≤ 9.9×10-9). In a larger cohort consisting of 597 GC patients and 9,759 healthy controls genotyped with SNP array, we discovered common variants in MUC4 regions (rs148735556, rs11717039, and rs547775645) significantly associated with GC supporting the association of MUC4 with gastric cancer. And the MUC4 variants were found in higher frequency in The Cancer Genome Atlas Study (TCGA) germline samples of patients with multiple cancer types. Immunohistochemistry indicated that MUC4 was downregulated in the noncancerous gastric mucosa of subjects with MUC4 germline missense variants, suggesting that loss of the protective function of MUC4 predisposes an individual to gastric cancer. Rare variants in MUC4 can be novel gastric cancer susceptibility loci in Koreans possessing the familial clustering of gastric cancer.

Association of current Helicobacter pylori infection and metabolic factors with gastric cancer in 35,519 subjects: A cross-sectional study

Background

The effect of current infection of Helicobacter pylori on gastric cancer has rarely been studied in a large population. We investigated the association of current H. pylori infection and metabolic factors with gastric cancer in a large population.

Methods

Persons who made their first visit to the National Cancer Center for a health examination, including endoscopy and H. pylori testing using gastric tissue between 2003 and 2013, were included. The association of H. pylori with gastric cancer was estimated using odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Among 35,519 people, 113 gastric cancer and 158 gastric dysplasia cases were detected. In the adjusted analysis, gastric cancer was associated with current H. pylori infection (OR, 2.39; 95% CI, 1.53-3.74), age (OR, 1.06; 95% CI 1.04-1.08), first-degree relatives with gastric cancer (OR, 2.08; 95% CI, 1.30-3.32) and hyperglycaemia (OR, 1.66; 95% CI, 1.04-2.65), whereas it was inversely associated with high-density lipoprotein (HDL) (OR, 0.49; 95% CI, 0.22-0.94). In the subanalysis, gastric cancer was associated with first-degree relatives with gastric cancer (OR, 3.23; 95% CI, 1.39-7.50) in the absence of H. pylori, whereas it was associated with hyperglycaemia (OR, 1.98; 95% CI, 1.16-3.39) in the presence of H. pylori.

Conclusions

Gastric cancer was associated with current H. pylori infection, hyperglycaemia, and low HDL levels in a large population.

Gastric cancer and family history

Gastric cancer is associated with high morbidity and mortality rates worldwide. Identifying individuals at high risk is important for surveillance and prevention of gastric cancer. Having first-degree relatives diagnosed with gastric cancer is a strong and consistent risk factor for gastric cancer, but the pathogenic mechanisms behind this familial aggregation are unclear. Against this background, we reviewed the risk factors for gastric cancer in those with a first-degree relative with gastric cancer, and the possible causes for familial clustering of gastric cancer including bacterial factors, inherited genetic susceptibility, environmental factors or a combination thereof. Among individuals with a family history, current or past Helicobacter pylori infection, having two or more first-degree affected relatives or female gender was associated with an increased risk of developing gastric cancer. To date, no specific single nucleotide polymorphism has been shown to be associated with familial clustering of gastric cancer. H. pylori eradication is the most important strategy for preventing gastric cancer in first-degree relatives of gastric cancer patients, particularly those in their 20s and 30s. Early H. pylori eradication could prevent the progression to intestinal metaplasia and reduce the synergistic effect on gastric carcinogenesis in individuals with both H. pylori infection and a family history. Endoscopic surveillance is also expected to benefit individuals with a family history. Further large-scale, prospective studies are warranted to evaluate the cost-effectiveness and optimal time point for endoscopy in this population. Moreover, genome-wide association studies that incorporate environmental and dietary factors on a 'big data' basis will increase our understanding of the pathogenesis of gastric cancer.