Sociodemographic and Lifestyle Factors in Relation to Gastric Cancer in a High-Risk Region of China: A Matched Case-Control Study

Tea consumption and gastric cancer: a pooled analysis from the Stomach cancer Pooling (StoP) Project consortium

BACKGROUND

Evidence from epidemiological studies on the role of tea drinking in gastric cancer risk remains inconsistent. We aimed to investigate and quantify the relationship between tea consumption and gastric cancer in the Stomach cancer Pooling (StoP) Project consortium.

METHODS

A total of 9438 cases and 20,451 controls from 22 studies worldwide were included. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) of gastric cancer for regular versus non-regular tea drinkers were estimated by one and two-stage modelling analyses, including terms for sex, age and the main recognised risk factors for gastric cancer.

RESULTS

Compared to non-regular drinkers, the estimated adjusted pooled OR for regular tea drinkers was 0.91 (95% CI: 0.85-0.97). When the amount of tea consumed was considered, the OR for consumption of 1-2 cups/day was 1.01 (95% CI: 0.94-1.09) and for >3 cups/day was 0.91 (95% CI: 0.80-1.03). Stronger inverse associations emerged among regular drinkers in China and Japan (OR: 0.67, 95% CI: 0.49-0.91) where green tea is consumed, in subjects with H. pylori infection (OR: 0.68, 95% CI: 0.58-0.80), and for gastric cardia cancer (OR: 0.64, 95% CI: 0.49-0.84).

CONCLUSION

Our results indicate a weak inverse association between tea consumption and gastric cancer.

Cancer Etiology and Prevention Principle: "1 + X"

Cancer was previously thought to be an inevitable aspect of human health with no effective treatments. However, the results of in-depth cancer research suggest that most types of cancer may be preventable. Therefore, a comprehensive understanding of the disparities in cancer burden caused by different risk factors is essential to inform and improve cancer prevention and control. Here, we propose the cancer etiology and prevention principle "1 + X," where 1 denotes the primary risk factor for a cancer and X represents the secondary contributing risk factors for the cancer. We elaborate upon the "1 + X" principle with respect to risk factors for several different cancer types. The "1 + X" principle can be used for precise prevention of cancer by eliminating the main cause of a cancer and minimizing the contributing factors at the same time.

Family History and Risk of Upper Gastrointestinal Cancer in the Linxian General Population

OBJECTIVE

The objective of this study was to investigate family history (FH) of upper gastrointestinal (UGI) cancer and risk of esophageal squamous cell carcinoma (ESCC), gastric cardia carcinoma (GCC), and gastric non-cardia carcinoma (GNCC) in the Linxian General Population Nutrition Intervention Trial (NIT) cohort. Methods: This prospective analysis was conducted using the Linxian NIT cohort data. Subjects with FH of UGI cancer was treated as an exposed group while the remainders were considered as a comparison group. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between FH of UGI cancer and risk of UGI cancer incidence and mortality were estimated using Cox proportional hazards models.

RESULTS

There were 5,680 newly diagnosed UGI cancer cases during the follow-up period, with a total of 4,573 UGI cancer deaths occurred, including 2,603 ESCC, 1,410 GCC, and 560 GNCC deaths. A positive FH of UGI cancer was associated with a significantly increased risk of ESCC and GCC (Incidence: HRESCC = 1.45, 95%CI: 1.35-1.56; HRGCC = 1.27, 95%CI: 1.15-1.40; Mortality: HRESCC = 1.40, 95%CI: 1.30-1.52; HRGCC = 1.27, 95%CI: 1.14-1.42) after adjusting for age at baseline, gender, smoking status, alcohol drinking, education level, and frequency of fresh fruit and vegetable consumption. Subjects with FH in both parents had the highest risk of ESCC and GCC incidence (HRESCC = 1.65, 95%CI: 1.40-1.95; HRGCC = 1.42, 95%CI: 1.12-1.81) and deaths (HRESCC = 1.65, 95%CI: 1.38-1.97; HRGCC = 1.42, 95%CI: 1.09-1.85). Spouse diagnosed with UGI cancer did not increase the risk of any UGI cancers of the subjects. In subgroup analysis, FH of UGI cancer was shown to significantly increase the risk of GCC in non-drinkers (Incidence: HR = 1.31, 95%CI: 1.17-1.47; Mortality: HR = 1.33, 95%CI: 1.17-1.50). No associations were observed for risk of GNCC. Sensitivity analysis by excluding subjects who were followed up less than three years did not materially alter our results.

CONCLUSION

Our data point to the role of the FH of UGI cancer to the risk of ESCC and GCC incidence and mortality. The influence of family history on the risk of UGI cancer varies from different types of family members.

Relationship between MEG3 gene polymorphism and risk of gastric cancer in Chinese population with high incidence of gastric cancer

Objective: Gastric cancer is the most common gastrointestinal malignancy in China and results from a combination of genetic and environmental factors. The present study was conducted to investigate the relationship between long noncoding RNA (lncRNA) materally expressed gene 3 (MEG3) single nucleotide polymorphisms (SNPs) and the risk of gastric cancer and to construct a genetic-environmental risk assessment model. Methods: A case–control study was conducted to include 474 patients with gastric cancer diagnosed by clinical and pathological examination and 543 healthy physical examination subjects. Blood samples, general demographic data and behavioral lifestyle of the subjects were collected. The TaqMan real-time PCR method was used for testing the genotypes of MEG3 rs7158663 and rs10132552. Results: The A allele at the rs7158663 loci of MEG3 was found to be risk factor for gastric cancer (odds ratio (OR) = 1.41, 95% confidence interval (95% CI) = 1.14–1.74, P=0.002). Yet, no significant association between rs10132552 polymorphisms and gastric cancer was observed. Drinking, tea drinking and preserved food eating were risk factors for gastric cancer (P<0.05). A genetic–environmental risk assessment model was established by using the logistic regression model to include MEG3 rs7158663, drinking, tea drinking, and preserved food eating. With the increase in risk score (RS), the risk of gastric cancer increased substantially (P<0.05). And the area under the receiver operating characteristic (ROC) curve was 0.745, which indicates a high diagnostic value. Conclusions:MEG3 rs7158663 might be associated with the risk of gastric cancer; the diagnostic ability of genetic–environmental risk assessment model for gastric cancer is better.

Genetic variants in the regulation region of TLR4 reduce the gastric cancer susceptibility

Gastric cancer (GC) is one of the most common cancers diagnosed in China. It has been suggested that the genetic polymorphisms of Toll-like receptors (TLRs) might be in close relation to tumorigenesis and development of gastric cancer. In this study, we performed a case-control study to investigate the genetic polymorphisms of TLR3, 4, 5, 7 with the genetic susceptibility of gastric cancer. TLRs gene polymorphisms in 471 gastric cancer (GC) patients and 471 healthy controls were analyzed by polymerase chain reaction-restrictive fragment length polymorphism (PCR-RFLP) analysis or TaqMan assays. Odds ratio (OR) and its 95% confidence interval (95%CI) were used to evaluate the association of TLR4 variants with the GC risk via unconditional logistic regression. Our results suggested that variant genotypes of TLR4 rs7869402 (OR = 0.61, 95%CI = 0.40-0.92, P = 0.02) and TLR4 rs7873784 (OR = 0.17, 95%CI = 0.09-0.33, P < 0.01) gene polymorphisms reduced the risk of GC. Stratified analysis showed that rs7869402 T-containing genotype significantly decreased the susceptibility of GC among females (OR = 0.38, 95%CI = 0.16-0.91, P = 0.03), older subjects (OR = 0.48, 95%CI = 0.26-0.87, P = 0.02), non-smokers (OR = 0.41, 95%CI = 0.23-0.71, P < 0.01) and non-drinkers (OR = 0.58, 95%CI = 0.30-0.78, P < 0.01). In case of rs7873784 polymorphism, C-containing genotype reduced the risk of GC among males (OR = 0.08, 95%CI = 0.03-0.21, P < 0.01), but not among females (OR = 0.53, 95%CI = 0.22-1.27, P = 0.15). As to the other four SNPs (TLR3 rs5743303, TLR4 rs1927914, TLR5 rs1640816 and TLR7 rs3853839), no significant correlations were found to be related to the risk of gastric carcinoma. Our research demonstrated the significance of TLRs polymorphisms in decreasing the risk of GC.