Increased risk of developing digestive tract cancer in subjects carrying the PLCE1 rs2274223 A>G polymorphism: evidence from a meta-analysis

The PLCE1 rs2274223 variant is associated with the risk of laryngeal squamous cell carcinoma

Background: Laryngeal squamous cell carcinoma (LSCC) ranks second in the mortality rate in respiratory malignant tumors and has potential similarity in genomic alterations with the esophageal squamous cell carcinoma (ESCC). The PLCE1 rs2274223 variant is the most significant susceptibility loci identified in ESCC. Whether it is also associated with LSCC susceptibility is still unclear. Materials and Methods: A total of 331 LSCC patients and 349 healthy controls were recruited in this study. The PLCE1 rs2274223 variant was genotyped by using the Taqman SNP Genotyping Assay. Association between PLCE1 rs2274223 variant and LSCC risk was estimated by logistic regression analysis, which was performed using SAS software. Results: The PLCE1 rs2274223 variant was identified to be significantly associated with the susceptibility of LSCC in the additive model (OR = 1.40, 95% CI: 1.06-1.86, P=0.019). Compared with the wild-type (AA) carriers, the risk genotype (GG) carriers had a 2.8-fold risk of LSCC (95% CI: 1.13-7.06, P=0.026). Stratified analysis showed that the association between rs2274223 and LSCC risk was with higher significance in individuals above 60 (P = 0.027) males (P = 0.030) or non-smokers (P = 0.026). Conclusion: The PLCE1 rs2274223 variant was significantly associated with risk of LSCC, which may be a potential biomarker and therapeutic target for the LSCC.

The controversial role of phospholipase C epsilon (PLCε) in cancer development and progression

The phospholipase C (PLC) enzymes are important regulators of membrane phospholipid metabolism. PLC proteins can be activated by the receptor tyrosine kinases (RTK) or G-protein coupled receptors (GPCR) in response to the different extracellular stimuli including hormones and growth factors. Activated PLC enzymes hydrolyze phosphoinositides to increase the intracellular level of Ca²⁺ and produce diacylglycerol, which are important mediators of the intracellular signaling transduction. PLC family includes 13 isozymes belonging to 6 subfamilies according to their domain structures and functions. Although importance of PLC enzymes for key cellular functions is well established, the PLC proteins belonging to the ε, ζ and η subfamilies were identified and characterized only during the last decade. As a largest known PLC protein, PLCε is involved in a variety of signaling pathways and controls different cellular properties. Nevertheless, its role in carcinogenesis remains elusive.

The aim of this review is to provide a comprehensive and up-to-date overview of the experimental and clinical data about the role of PLCε in the development and progression of the different types of human and experimental tumors.

The Antiproliferative Effect of Chakasaponins I and II, Floratheasaponin A, and Epigallocatechin 3-O-Gallate Isolated from Camellia sinensis on Human Digestive Tract Carcinoma Cell Lines

Acylated oleanane-type triterpene saponins, namely chakasaponins I (1) and II (2), floratheasaponin A (3), and their analogs, together with catechins—including (–)-epigallocatechin 3-O-gallate (4), flavonoids, and caffeine—have been isolated as characteristic functional constituents from the extracts of “tea flower”, the flower buds of Camellia sinensis (Theaceae), which have common components with that of the leaf part. These isolates exhibited antiproliferative activities against human digestive tract carcinoma HSC-2, HSC-4, MKN-45, and Caco-2 cells. The antiproliferative activities of the saponins (1–3, IC₅₀ = 4.4–14.1, 6.2–18.2, 4.5–17.3, and 19.3–40.6 µM, respectively) were more potent than those of catechins, flavonoids, and caffeine. To characterize the mechanisms of action of principal saponin constituents 1–3, a flow cytometric analysis using annexin-V/7-aminoactinomycin D (7-AAD) double staining in HSC-2 cells was performed. The percentage of apoptotic cells increased in a concentration-dependent manner. DNA fragmentation and caspase-3/7 activation were also detected after 48 h. These results suggested that antiproliferative activities of 1–3 induce apoptotic cell death via activation of caspase-3/7.

Cytochrome P450 1A1 gene polymorphisms and digestive tract cancer susceptibility: a meta-analysis

Cytochrome P450 1A1 (CYP1A1) is a phase I enzyme that regulates the metabolism of environmental carcinogens and alter the susceptibility to various cancers. Many studies have investigated the association between the CYP1A1 MspI and Ile462Val polymorphisms and digestive tract cancer (DTC) risk in different groups of populations, but their results were inconsistent. The PubMed and Embase Database were searched for case–control studies published up to 30th September, 2015. Data were extracted and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the relationship. Totally, 39 case–control studies (9094 cases and 12,487 controls) were included. The G allele in Ile/Val polymorphism was significantly associated with elevated DTC risk with per‐allele OR of 1.24 (95% CI = 1.09–1.41, P = 0.001). Similar results were also detected under the other genetic models. Evidence was only found to support an association between MspI polymorphism and DTC in the subgroups of caucasian and mixed individuals, but not in the whole population (the dominant model: OR = 1.19, 95% CI = 0.94–1.91, P = 0.146). In conclusion, our results suggest that the CYP1A1 polymorphisms are potential risk factors for DTC. And large sample size and well‐designed studies with detailed clinical information are needed to more precisely evaluate our founding.

Genetic polymorphism of miR-146a is associated with gastric cancer risk: a meta-analysis

Several studies have investigated the associations between miR-146a rs2910164 and gastric cancer (GC) risk, but results have been inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. PubMed and China National Knowledge Infrastructure searches were carried out for relevant studies published before July 2014. Meta-analysis was performed with the stata, version 11.0. A total of seven case-control studies, including 3283 cases and 4535 controls, were selected. A significant association was found between rs2910164 and GC risk under all genetic models (CC vs. GG, OR = 0.76, 95% CI = 0.66-0.87; CC vs. GC+GG, OR = 0.84, 95% CI = 0.71-0.99; CC+GC vs. GG, OR = 0.82, 95% CI = 0.73-0.91) for the total data. In the subgroup analysis by ethnicity, statistically significant association was found in Asian. This meta-analysis suggested that the miR-146a rs2910164 was a risk factor for developing GC.

Associations of genetic variants in the PSCA, MUC1 and PLCE1 genes with stomach cancer susceptibility in a Chinese population

BACKGROUND

Several genetic variants including PSCA rs2294008 C>T and rs2976392 G>A, MUC1 rs4072037 T>C, and PLCE1 rs2274223 A>G have shown significant association with stomach cancer risk in the previous genome-wide association studies (GWASs).

METHODS

To evaluate associations of these SNPs in the Han Chinese, an independent hospital based case-control study was performed by genotyping these four polymorphisms in a total of 692 stomach cancer cases and 774 healthy controls acquired by using frequency matching for age and gender. False-positive report probability (FPRP) analysis was also performed to validate all statistically significant findings.

RESULTS

In the current study, significant association with stomach cancer susceptibility was observed for all the four polymorphisms of interest. Specifically, a significant increased stomach cancer risk was associated with PSCA rs2294008 (CT vs. CC: adjusted OR = 1.37, 95% CI = 1.07-1.74, and CT/TT vs.CC: adjusted OR = 1.30, 95% CI = 1.03-1.63), PSCA rs2976392 (AG vs. GG: adjusted OR = 1.30, 95% CI = 1.02-1.65, and AG/AA vs. GG: adjusted OR = 1.26, 95% CI = 1.00-1.59), or PLCE1 rs2274223 (AG vs. AA: adjusted OR = 1.48, 95% CI = 1.15-1.90, and AG/GG vs. AA: adjusted OR = 1.45, 95% CI = 1.14-1.84), respectively. In contrast, MUC1 rs4072037 was shown to decrease the cancer risk (CT vs. TT: adjusted OR = 0.77, 95% CI = 0.60-0.98). Patients with more than one risk genotypes had significant increased risk to develop stomach cancer (adjusted OR = 1.30, 95% CI = 1.03-1.64), when compared with those having 0-1 risk genotypes. Stratified analysis indicated that the increased risk was more pronounced in younger subjects, men, ever smokers, smokers with pack years ≤ 27, patients with high BMI, or non-cardia stomach cancer.

CONCLUSIONS

This study substantiated the associations between four previous reported genetic variants and stomach cancer susceptibility in an independent Han Chinese population. Further studies with larger sample size and different ethnicities are warranted to validate our findings.

PLCE1 rs2274223 polymorphism contributes to risk of esophageal cancer: evidence based on a meta-analysis

We sought to reassess the association of PLCE1 rs2274223 and susceptibility to esophageal cancer (EC) through a meta-analysis of published case-control studies. Using the PubMed and Embase, we identified nine articles including fourteen case-control studies (15,225 cases and 23,620 controls). ORs and 95 % confidence intervals (CIs) of GG vs. AA, GG + GA vs. AA, GG vs. GA + AA, G vs. A, and AG vs. AA genetic models were estimated for each study. All of the genetic models indicated a statistically significant positive association with EC risk. The association appeared most pronounced for carriers of GG genotype (GG vs. AA: OR, 1.35; 95 % CI, 1.17 to 1.57), and weakest for individuals carrying GA genotype (GA vs. AA: OR, 1.13; 95 % CI, 1.05 to 1.23). Stratification analyses showed similar results in the population of Asians and in esophageal squamous cell carcinoma (ESCC). This meta-analysis provides strong statistical evidence for an elevated risk of EC associated with PLCE1 rs2274223. The association remains significant in Asian population and ESCC. Further investigations are warranted to validate these findings.

Phospholipase C epsilon 1 (PLCE1) haplotypes are associated with increased risk of gastric cancer in Kashmir Valley

BACKGROUND/AIM

Phospholipase C epsilon 1 (PLCE1) plays a crucial role in carcinogenesis and progression of several types of cancers. A single nucleotide polymorphism (SNP, rs2274223) in PLCE1 has been identified as a novel susceptibility locus. The aim of the present study was to investigate the role of three potentially functional SNPs (rs2274223A > G, rs3765524C > T, and rs7922612C > T) of PLCE1 in gastric cancer patients from Kashmir Valley.

PATIENTS AND METHODS

The study was conducted in 108 GC cases and 195 healthy controls from Kashmir Valley. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism method. Data were statistically analyzed using c2 test and logistic regression models. A P value of less than 0.05 was regarded as statistically significant.

RESULTS

The frequency of PLCE1 A2274223C3765524T7922612, G2274223C3765524T7922612 , and G2274223T3765524C7922612 haplotypes were higher in patients compared with controls, conferred high risk for GC [odds ratio (OR) =6.29; P = 0.001; Pcorr = 0.003], (OR = 3.23; P = 0.011; Pcorr = 0.033), and (OR = 5.14; P = 0.011; Pcorr = 0.033), respectively. Smoking and salted tea are independent risk factors for GC, but we did not find any significant modulation of cancer risk by PLCE1 variants with smoking or excessive consumption of salted tea.

CONCLUSION

These results suggest that variation in PLCE1 may be associated with GC risk in Kashmir Valley.

MDM2 SNP309 is an ethnicity-dependent risk factor for digestive tract cancers

Published data on the relationship between T309G polymorphism in the murine double minute 2 (MDM2) gene and susceptibility of digestive tract cancers (DTC) are inconclusive. Thus, the aim of this study is to determine whether MDM2 T309G polymorphism is associated with the risk of diverse DTC, including esophagus, stomach, liver, bile duct, pancreas, and colorectum cancers. Relevant studies were identified up to October 1, 2013. Crude odds ratio (OR) and 95% confidence interval (CI) were used as a measure of the strength of the association. The pooled result based on all studies showed that there was a statistically significant link between MDM2 T309G polymorphism and DTC susceptibility (T vs. G: OR = 0.82, 95%CI = 0.76-0.88). When stratified by race, significant associations were observed for all genetic models among Asians (especially in Chinese population), but not among Caucasians. Subgroup analyses according to tumor location indicated that the genetic variant was associated with esophageal (OR = 0.88, 95%CI = 0.81-0.96 for T vs. G), hepatocellular (OR = 0.69, 95%CI = 0.57-0.84 for T vs. G) and pancreatic cancer risk but not associated with cholangiocarcinoma or colorectum cancer susceptibility. Meanwhile, the G allele was also suggested to be associated with increased gastric cancer risk (OR = 0.68, 95%CI = 0.54-0.87 for TT + TG vs. GG for intestinal type of gastric cancer and OR = 0.18, 95%CI = 0.06-0.50 for TT vs. GG for Helicobacter pylori infection positive stomach cancer). Our study indicates that the MDM2 T309G polymorphism may be an ethnicity-dependent risk factor for DTC, especially for the upper gastrointestinal tract malignancies.