Regulatory links between PLC enzymes and Ras superfamily GTPases: signalling via PLCepsilon

PLCE1 Polymorphisms Are Associated With Gastric Cancer Risk: The Changes in Protein Spatial Structure May Play a Potential Role

Background

Gastric cancer (GC) is one of the most significant health problems worldwide. Some studies have reported associations between Phospholipase C epsilon 1 (PLCE1) single-nucleotide polymorphisms (SNPs) and GC susceptibility, but its relationship with GC prognosis lacked exploration, and the specific mechanisms were not elaborated fully yet. This study aimed to further explore the possible mechanism of the association between PLCE1 polymorphisms and GC.

Materials and Methods

A case-control study, including 588 GC patients and 703 healthy controls among the Chinese Han population, was performed to investigate the association between SNPs of PLCE1 and GC risk by logistic regression in multiple genetic models. The prognostic value of PLCE1 in GC was evaluated by the Kaplan-Meier plotter. To explored the potential functions of PLCE1, various bioinformatics analyses were conducted. Furthermore, we also constructed the spatial structure of PLCE1 protein using the homology modeling method to analyze its mutations.

Results

Rs3765524 C > T, rs2274223 A > G and rs3781264 T > C in PLCE1 were associated with the increased risk of GC. The overall survival and progression-free survival of patients with high expression of PLCE1 were significantly lower than those with low expression [HR (95% CI) = 1.38 (1.1–1.63), P < 0.01; HR (95% CI) = 1.4 (1.07–1.84), P = 0.01]. Bioinformatic analysis revealed that PLCE1 was associated with protein phosphorylation and played a crucial role in the calcium signal pathway. Two important functional domains, catalytic binding pocket and calcium ion binding pocket, were found by homology modeling of PLCE1 protein; rs3765524 polymorphism could change the efficiency of the former, and rs2274223 polymorphism affected the activity of the latter, which may together play a potentially significant role in the tumorigenesis and prognosis of GC.

Conclusion

Patients with high expression of PLCE1 had a poor prognosis in GC, and SNPs in PLCE1 were associated with GC risk, which might be related to the changes in spatial structure of the protein, especially the variation of the efficiency of PLCE1 in the calcium signal pathway.

The effects of mutant Ras proteins on the cell signalome

The genetic alterations in cancer cells are tightly linked to signaling pathway dysregulation. Ras is a key molecule that controls several tumorigenesis-related processes, and mutations in RAS genes often lead to unbiased intensification of signaling networks that fuel cancer progression. In this article, we review recent studies that describe mutant Ras-regulated signaling routes and their cross-talk. In addition to the two main Ras-driven signaling pathways, i.e., the RAF/MEK/ERK and PI3K/AKT/mTOR pathways, we have also collected emerging data showing the importance of Ras in other signaling pathways, including the RAC/PAK, RalGDS/Ral, and PKC/PLC signaling pathways. Moreover, microRNA-regulated Ras-associated signaling pathways are also discussed to highlight the importance of Ras regulation in cancer. Finally, emerging data show that the signal alterations in specific cell types, such as cancer stem cells, could promote cancer development. Therefore, we also cover the up-to-date findings related to Ras-regulated signal transduction in cancer stem cells.

Genetic variants in GHR and PLCE1 genes are associated with susceptibility to esophageal cancer

Background

Esophageal cancer (EC) is the leading cause of cancer‐related mortality worldwide. The underlying genetic risk factors remain unclear. The association between gene growth hormone receptor (GHR) and phospholipase C epsilon 1 (PLCE1) polymorphisms and the EC risk were identified in this study.

Methods

A total of 506 EC cases and 507 controls were included in this research. Two SNPs (rs6898743 of GHR and rs2274223 of PLCE1) were selected and genotyped. The associations between gene polymorphisms and the EC risk were assessed by logistic regression analysis. The databases RegulomeDB, GTEx, and UALCAN were used for functional annotations.

Results

In the allelic frequencies analysis, the rs6898743 of GHR was associated with decreased susceptibility of EC (OR = 0.83, 95% CI: 0.70–1.00, p = 0.049), while rs2274223 of PLCE1 was associated with increased 0.25‐fold EC risk (OR = 1.25, 95% CI: 1.02–1.53, p = 0.037). The “GC” genotype of rs6898743 was associated with a 0.24‐fold decreased risk of EC under co‐dominant model (OR = 0.76, 95% CI: 0.58–0.99, p = 0.046), and the “GA” genotype of rs2274223 was associated with increased EC risk under co‐dominant model (OR = 1.36, 95% CI: 1.04–1.77, p = 0.023). Using GTEx database, rs2274223 was found to be significant associated with increased PLCE1 expression (p = 4.1 × 10⁻⁷) in esophagus muscularis. The UALCAN database demonstrated that the GHR gene was under‐expressed in esophageal cancer tissues (p = 0.017).

Conclusion

The gene GHR and PLCE1 polymorphisms are associated with EC in the general population and the results need to be verified in future.

PLCε knockdown enhances the radiosensitivity of castration‑resistant prostate cancer via the AR/PARP1/DNA‑PKcs axis

Radiotherapy (RT) has been used as a therapeutic option for treatment of prostate cancer (PCa) for a number of years; however, patients frequently develop RT resistance, particularly in castration-resistant PCa (CRPC), although the underlying mechanisms remain unknown. Understanding the underlying mechanism of RT resistance in CRPC may potentially highlight novel targets to improve therapeutic options for patients with PCa. In the present study, the expression levels of phospholipase Cε (PLCε), androgen receptor (AR) and DNA-dependent protein kinase catalytic subunit (PKcs) were examined in PCa tissue samples and PCa cells, and the effects of PLCε knockdown on AR and DNA damage repair (DDR)-related molecules were determined. The association between PLCε, AR and Poly (ADP-ribose) polymerase 1 (PARP1), as well as their respective roles in radiation resistance, were assessed using gene knockdown and pharmaceutical inhibitors or activators. A chromatin immunoprecipitation assay was used to determine the epigenetic regulatory effects of PLCε on PARP1. Animal experiments were performed to assess whether the mechanisms observed in vitro could be replicated in vivo. The expression levels of PLCε, AR and DNA-PKcs were significantly upregulated in PCa, particularly in CRPC. PLCε knockdown reduced the viability and increased apoptosis of cells subjected to radiation. Additionally, PLCε deficiency suppressed DDR progression by downregulating an AR and PARP1 positive feedback loop and the associated downstream molecules following radiation. PLCε depletion also increased the presence of histone H3 lysine 27 trimethylation in the PARP1 promoter region, suggesting increased methylation of the PARP1 gene and thus resulting in reduced expression of PARP1. In vivo, PLCε knockdown significantly potentiated the effects of radiation on tumor growth. Taken together, the results of the present study demonstrated that PLCε knockdown enhanced the radiosensitivity of CRPC by downregulating the AR/PARP1/DNA-PKcs axis.

Oncogene PLCE1 may be a diagnostic biomarker and prognostic biomarker by influencing cell cycle, proliferation, migration, and invasion ability in hepatocellular carcinoma cell lines

Hepatocellular carcinoma (HCC) is a lethal malignancy worldwide. HCC has traits of late diagnosis and high recurrence. This study explored potential diagnosis and prognosis significance of phospholipase C epsilon 1 (PLCE1) in HCC. The messenger RNA (mRNA) levels and diagnostic value of PLCE1 were determined by real-time polymerase chain reaction and online databases GEPIA, oncomine, and GSE14520 data set. Survival analysis used the Kaplan-Meier Plotter website. Cell cycle, proliferation, migration, and invasion assays were performed with downregulated PLCE1 expression in HCC-M and HepG2 cell lines. PLCE1 was differentially expressed and highly expressed in tumors and had low expression in nontumor tissues (all p < .05). The diagnostic value of PLCE1 was validated with the datasets (all p < .01, all areas under curves > 0.7). PLCE1 mRNA expression was associated with the overall and relapse-free survival (both p < .05). Functional experiments indicated that downregulation of PLCE1 expression led to increased G1 stage in cell cycle and decreased cell proliferation, migration, and invasion compared with a negative control group (all p ≤ .05). The oncogene PLCE1 was differentially expressed in HCC and non-HCC tissues. It is a candidate for diagnosis and serves as prognosis biomarker. PLCE1 influenced survival by affecting the cell cycle, proliferation, migration, and invasion ability.

PLCε regulates prostate cancer mitochondrial oxidative metabolism and migration via upregulation of Twist1

Background

Metabolic rewiring is a common feature of many cancer types, including prostate cancer (PCa). Alterations in master genes lead to mitochondrial metabolic rewiring and provide an appealing target to inhibit cancer progression and improve survival. Phospholipase C (PLC)ε is a regulator of tumor generation and progression. However, its role in mitochondrial metabolism remains unclear.

Methods

The GEO, The Cancer Genome Atlas, and the GTEx databases were used to determine Twist1 mRNA levels in tumors and their non-tumor counterparts. Fifty-five PCa and 48 benign prostatic hypertrophy tissue samples were tested for the presence of PLCε and Twist1 immunohistochemically. An association between PLCε and Twist1 was determined by Pearson’s correlation analysis. PLCε was knocked down with a lentiviral short hairpin RNA. Mitochondrial activity was assessed by measuring the oxygen consumption rate. Western blotting analyses were used to measure levels of PPARβ, Twist1, phosphorylated (p)-Twist1, p-MEK, p-ERK, p-P38, and p-c-Jun N-terminal kinase (JNK). Cells were treated with inhibitors of MEK, JNK, and P38 MAPK, and an agonist and inhibitor of peroxisome proliferator activated receptor (PPAR) β, to evaluate which signaling pathways were involved in PLCε-mediated Twist1 expression. The stability of Twist1 was determined after blocking protein synthesis with cycloheximide. Reporter assays utilized E-cadherin or N-cadherin luciferase reporters under depletion of PLCε or Twist1. Transwell assays assessed cell migration. Finally, a nude mouse tumor xenograft assay was conducted to verify the role of PLCε in tumor formation.

Results

Our findings revealed that the expression of PLCε was positively associated with Twist1 in clinical PCa samples. PLCε knockdown promoted mitochondrial oxidative metabolism in PCa cells. Mechanistically, PLCε increased phosphorylation of Twist1 and stabilized the Twist1 protein through MAPK signaling. The transcriptional activity of Twist1, and the Twist1-mediated epithelial-to-mesenchymal transition, cell migration, and transcription regulation, were suppressed by PLCε knockdown and by blocking PPARβ nuclear translocation. The tumor xenograft assay demonstrated that PLCε depletion diminished PCa cell tumorigenesis.

Conclusions

These findings reveal an undiscovered physiological role for PLCε in the suppression of mitochondrial oxidative metabolism that has significant implications for understanding PCa occurrence and migration.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1323-8) contains supplementary material, which is available to authorized users.

Covariance-Insured Screening

Modern bio-technologies have produced a vast amount of high-throughput data with the number of predictors far greater than the sample size. In order to identify more novel biomarkers and understand biological mechanisms, it is vital to detect signals weakly associated with outcomes among ultrahigh-dimensional predictors. However, existing screening methods, which typically ignore correlation information, are likely to miss weak signals. By incorporating the inter-feature dependence, a covariance-insured screening approach is proposed to identify predictors that are jointly informative but marginally weakly associated with outcomes. The validity of the method is examined via extensive simulations and a real data study for selecting potential genetic factors related to the onset of multiple myeloma.

Single Nucleotide Polymorphisms in PLCE1 for Cancer Risk of Different Types: A Meta-Analysis

Background: Recent studies have investigated the relationships between PLCE1 polymorphisms and cancer susceptibility. However, some findings lack consistency.

Objectives: In the current study, we conducted a meta-analysis to more accurately evaluate the relationships between PLCE1 (rs2274223, rs3765524, rs753724, rs11187842, and rs7922612) single nucleotide polymorphisms (SNPs) and risk for different types of cancer.

Methods: We performed a comprehensive search strategy in PubMed, Web of Science, Medline, EMbase, and Scopus for articles available until 19 March 2018. A total of 54 case-control studies comprising 17,955 cases and 20,400 controls were included in the current meta-analysis, which together comprised a total of 32 publications. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate relationships between the PLCE1 polymorphisms and cancer susceptibility. All statistical analyses were performed using Stata 11 software.

Results: Results of the meta-analysis demonstrated that the rs2274223 polymorphism showed a significant correlation with increased overall cancer susceptibility (AG vs. AA: OR 1.168, 95% CI 1.084–1.259; GG vs. AA: OR 1.351, 95% CI 1.163–1.570; AG+GG vs. AA: OR 1.193, 95% CI 1.103–1.290; GG vs. AA+AG: OR 1.262, 95% CI 1.102–1.446; G vs. A: OR 1.163, 95% CI 1.089–1.242). Results of subgroup analysis showed that the rs2274223 polymorphism was associated with higher risk for esophageal cancer and gastric cancer relative to colorectal cancer and head and neck cancer. In addition, the rs2274223 polymorphism was found to be associated with increased cancer risk, especially among the subgroups comprising Asians, studies with population-based controls, studies employing the TaqMan genotyping method, and studies consistent with Hardy-Weinberg equilibrium (HWE). The association between the rs3765524 polymorphism and reduced overall cancer risk was detected in one specific genetic model (CT vs. CC: OR 0.681, 95% CI 0.523–0.886). Results of subgroup analysis showed that the rs3765524 polymorphism was associated with cancer risk in a specific genetic model among the subgroups of colorectal cancer, esophageal cancer, Asians, studies with population-based controls, and studies consistent with HWE. However, relationships among the PLCE1 rs753724, rs11187842, and rs7922612 polymorphisms and tumor risk were not identified.

Conclusions: Results of the current meta-analysis suggested that PLCE1 (rs2274223, rs3765524) polymorphisms are associated with cancer susceptibility.

PLCE1 polymorphisms and expression combined with serum AFP level predicts survival of HBV-related hepatocellular carcinoma patients after hepatectomy

Polymorphisms in the phospholipase C epsilon (PLCE) 1 gene play a crucial role in the development and progression of several types of cancer. The present study investigated the prognostic significance of PLCE1 gene polymorphisms and expression combined with serum α-fetoprotein (AFP) level in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Single nucleotide polymorphisms were genotyped by sequencing DNA isolated from surgically resected tumor samples of 421 HBV-related HCC patients, and expression profiles were generated based on the GSE14520 dataset. A joint-effects analysis of PLCE1 haplotypes (Ars2274223Crs3765524; Grs2274223Trs3765524) with AFP level stratified at 20 ng/ml showed a significant association with overall survival(OS) of HBV-related HCC patients(log-rank P=0.0003). Patients with AC and GT haplotypes with AFP level ≥ 20 ng/ml had an increased risk of death as compared to those with the AC haplotype and AFP level < 20 ng/ml (adjusted P=0.029 and 0.041, respectively). Patients with the GT haplotype and AFP level < 20 ng/ml also had an increased risk of death, although with a non-significant P value (adjusted P=0.092). Joint-effects analysis of PLCE1 mRNA expression with serum AFP level stratified at 300 ng/ml was significantly associated with HBV-related HCC recurrence and OS. Our results demonstrate that PLCE1 haplotypes (including rs2274223 and rs3765524) and expression combined with serum AFP level may predict postoperative outcome of HBV-related HCC patients.

Clinical significance of the correlation between PLCE 1 and PRKCA in esophageal inflammation and esophageal carcinoma

Esophagitis and Barrett's esophagus are linked to esophageal squamous cell carcinoma and adenocarcinoma, respectively. However, the underlying mechanisms are still unclear. This study analyzed the expression levels of and correlation between PLCE1 and PRKCA in human esophagitis, carcinogen NMBA-induced rat esophagus, PLCE1 genetic deficient mouse esophageal epithelial tissues and human esophageal cancer cell line, integrated with Online oncology data sets. We found that the expression levels of both PLCE1 and PRKCA were significantly elevated in human esophagitis, esophageal squamous cell carcinoma, Barrett's esophagus, esophageal adenocarcinoma and in NMBA-treated rat esophageal epithelia. However, PRKCA and cytokines were significantly downregulated in PLCE1-deficient mouse esophageal epithelia, and knockdown of PLCE1 in human esophageal cancer cells led to reduction of PRKCA and cytokines. Finally, high expression of both PLCE1 and PRKCA is significantly associated with poor outcomes of the patients with esophageal cancers. In conclusion, this study defined the initiation and progression of esophageal inflammation and malignant transformation, in which the positive correlation of PLCE1 and PRKCA exhibits critical clinical significance.

Bosco: Boosting Corrections for Genome-Wide Association Studies With Imbalanced Samples

In genome-wide association studies (GWAS), the acquired sequential data may exhibit imbalance structure: abundant control vs. limited case samples. Such sample imbalance issue is particularly serious when investigating rare diseases or common diseases on rare populations. Conventional GWAS methods may suffer from severe statistic biases to the major group, leading to power losses in uncovering true suspicious loci. We introduce a boosting correction method termed as Bosco to deal with such imbalanced problem. Bosco is motivated by the boost learning theory in machine learning and is implemented in a coarse-to-fine learning framework: the coarse step assigns importance scores for all samples in the major group and the fine step calculates P -values by a weighted logistic regression. On simulated data sets, we demonstrate the proposed methods can dramatically improve the discovery power even on extremely imbalanced datasets, with well controlling the false positives. The Bosco is also applied to a genome-scale gastric cancer data set to conduct genome-wide analysis. Our method replicates existing reported findings (from the likelihood ratio test) with high statistical significance and shows the ability to identify new suspicious SNPs.

Low PLCE1 levels are correlated with poor prognosis in hepatocellular carcinoma

Background

Previous reports show that phospholipase C epsilon-1 (PLCE1) expression is positively correlated with esophageal squamous cell carcinoma and gastric cardia adenocarcinomas; however, the expression of PLCE1 in hepatocellular carcinoma (HCC) and its correlation with clinical outcome still remain unclear. The aim of this study was to explore the expression of PLCE1 in HCC tissue and to determine whether PLCE1 was a prognostic factor for HCC patients.

Materials and methods

PLCE1 levels in 20 paired HCC tissues and corresponding paracarcinomatous tissues was investigated by quantitative real-time polymerase chain reaction and Western blot assays. In addition, protein levels of PLCE1 in one normal liver epithelial cell and four HCC cell lines were examined using Western blot assay. Moreover, immunohistochemistry was applied to determine the expression of PLCE1 in HCC and corresponding surrounding tissues from 90 patients. Statistical analyses were used to examine the association between PLCE1 levels and clinicopathological features.

Results

We found that the expression of PLCE1 in tumor tissues was significantly lower than those in paracarcinomatous tissues at both mRNA and protein levels (P<0.05). We also determined that PLCE1 protein expression levels were lower in HCC cell lines than normal liver epithelial cells (P<0.05). Notably, immunohistochemical assay showed that PLCE1 expression was significantly low in HCC tissues compared with the adjacent normal liver tissues (40% vs 18.9%; P<0.05). Besides, PLCE1 levels were negatively correlated with tumor capsulae, vascular invasion, Edmondson grade, alpha-fetoprotein, and tumor-node-metastasis stage (P<0.05). Univariate analysis revealed that lower level expression of PLCE1 was significantly associated with poorer overall survival (OS) rate (P<0.001) and disease-free survival rate (P<0.001). Multivariate analysis revealed that low PLCE1 level was an independent poor prognostic factor of OS and recurrence-free survival (P<0.001 and P=0.003, respectively).

Conclusion

In brief, our results revealed that decreased PLCE1 expression was associated with tumor progression in HCC and may function as a promising biomarker for HCC prognosis.

Targeting oncogenic PLCE1 by miR-145 impairs tumor proliferation and metastasis of esophageal squamous cell carcinoma

Phospholipase C epsilon 1 (PLCE1) is a susceptibility gene in esophageal squamous cell carcinoma (ESCC). Nevertheless, the role of PLCE1 in ESCC tumorigenesis has not been elucidated. In this study, we determined the function of PLCE1 and its regulatory microRNA (miRNA) in ESCC. PLCE1 protein was excessively expressed in ESCC and precancerous lesions compared with that in normal tissues. High PLCE1 expression levels in ESCC were significantly linked with poor overall survival. Knockdown of PLCE1 promoted the apoptosis, cytokine-induced apoptosis, and sensitivity of cancer cells to chemotherapeutic drugs but abrogated the proliferation and EMT phenotype of ESCC in vitro. Notably, miR-145 was newly identified as a potent repressor of PLCE1 expression by directly targeting the 3′UTR of PLCE1. MiR-145 also inhibited cell proliferation, migration, and metastasis, as well as controlled the cytoskeleton dynamics of esophageal cancer. Moreover, miR-145 was expressed at low levels in a large cohort of patients with ESCC and was inversely correlated with PLCE1 protein expression in cancer cells and tissues. These findings demonstrate that PLCE1 functions as tumor promoter in ESCC and can be suppressed by miR-145 through inhibition of PLCE1 translation. Hence, delivery of PLCE1-targeting miR-145 is a potential therapeutic approach for esophageal cancer.

Ras Conformational Ensembles, Allostery, and Signaling

Ras proteins are classical members of small GTPases that function as molecular switches by alternating between inactive GDP-bound and active GTP-bound states. Ras activation is regulated by guanine nucleotide exchange factors that catalyze the exchange of GDP by GTP, and inactivation is terminated by GTPase-activating proteins that accelerate the intrinsic GTP hydrolysis rate by orders of magnitude. In this review, we focus on data that have accumulated over the past few years pertaining to the conformational ensembles and the allosteric regulation of Ras proteins and their interpretation from our conformational landscape standpoint. The Ras ensemble embodies all states, including the ligand-bound conformations, the activated (or inactivated) allosteric modulated states, post-translationally modified states, mutational states, transition states, and nonfunctional states serving as a reservoir for emerging functions. The ensemble is shifted by distinct mutational events, cofactors, post-translational modifications, and different membrane compositions. A better understanding of Ras biology can contribute to therapeutic strategies.

Genetic variation and gastric cancer risk: a field synopsis and meta-analysis

BACKGROUND

Data on genetic susceptibility to sporadic gastric carcinoma have been published at a growing pace, but to date no comprehensive overview and quantitative summary has been available.

METHODS

We conducted a systematic review and meta-analysis of the evidence on the association between DNA variation and risk of developing stomach cancer. To assess result credibility, summary evidence was graded according to the Venice criteria and false positive report probability (FPRP) was calculated to further validate result noteworthiness. Meta-analysis was also conducted for subgroups, which were defined by ethnicity (Asian vs Caucasian), tumour histology (intestinal vs diffuse), tumour site (cardia vs non-cardia) and Helicobacter pylori infection status (positive vs negative).

RESULTS

Literature search identified 824 eligible studies comprising 2 530 706 subjects (cases: 261 386 (10.3%)) and investigating 2841 polymorphisms involving 952 distinct genes. Overall, we performed 456 primary and subgroup meta-analyses on 156 variants involving 101 genes. We identified 11 variants significantly associated with disease risk and assessed to have a high level of summary evidence: MUC1 rs2070803 at 1q22 (diffuse carcinoma subgroup), MTX1 rs2075570 at 1q22 (diffuse), PSCA rs2294008 at 8q24.2 (non-cardia), PRKAA1 rs13361707 5p13 (non-cardia), PLCE1 rs2274223 10q23 (cardia), TGFBR2 rs3087465 3p22 (Asian), PKLR rs3762272 1q22 (diffuse), PSCA rs2976392 (intestinal), GSTP1 rs1695 11q13 (Asian), CASP8 rs3834129 2q33 (mixed) and TNF rs1799724 6p21.3 (mixed), with the first nine variants characterised by a low FPRP. We also identified polymorphisms with lower quality significant associations (n=110).

CONCLUSIONS

We have identified several high-quality biomarkers of gastric cancer susceptibility. These data will form the backbone of an annually updated online resource that will be integral to the study of gastric carcinoma genetics and may inform future screening programmes.

Genetic variants and risk of gastric cancer: a pathway analysis of a genome-wide association study

This study aimed to discover candidate single nucleotide polymorphisms (SNPs) for hypothesizing significant biological pathways of gastric cancer (GC). We performed an Identify Candidate Causal SNPs and Pathways (ICSNPathway) analysis using a GC genome-wide association study (GWAS) dataset, including 472,342 SNPs in 2,240 GC cases and 3,302 controls of Asian ethnicity. By integrating linkage disequilibrium analysis, functional SNP annotation, and pathway-based analysis, seven candidate SNPs, four genes and 12 pathways were selected. The ICSNPathway analysis produced 4 hypothetical mechanisms of GC: (1) rs4745 and rs12904 → EFNA1 → ephrin receptor binding; (2) rs1801019 → UMPS → drug and pyrimidine metabolism; (3) rs364897 → GBA → cyanoamino acid metabolism; and (4) rs11187870, rs2274223, and rs3765524 → PLCE1 → lipid biosynthetic process, regulation of cell growth, and cation homeostasis. This pathway analysis using GWAS dataset suggests that the 4 hypothetical biological mechanisms might contribute to GC susceptibility.

PLCε knockdown inhibits prostate cancer cell proliferation via suppression of Notch signalling and nuclear translocation of the androgen receptor

Phospholipase Cε (PLCε), a key regulator of diverse cellular functions, has been implicated in various malignancies. Indeed, PLCε functions include cell proliferation, apoptosis and malignant transformation. Here, we show that PLCε expression is elevated in prostate cancer (PCa) tissues compared to benign prostate tissues. Furthermore, PLCε depletion using an adenovirally delivered shRNA significantly decreased cell growth and colony formation, arresting the PC3 and LNCaP cell lines in the S phase of the cell cycle. We also observed that PLCε was significantly correlated with Notch1 and androgen receptor (AR). Additionally, we demonstrate that the activation of both the Notch and AR signalling pathways is involved in PLCε-mediated oncogenic effects in PCa. Our findings suggest that PLCε is a putative oncogene and prognostic marker, potentially representing a novel therapeutic target for PCa.

HPV seropositivity joints with susceptibility loci identified in GWASs at apoptosis associated genes to increase the risk of Esophageal Squamous Cell Carcinoma (ESCC)

BACKGROUND

We previously showed that human papillomavirus (HPV) serostatus was not an independent risk factor for esophageal squamous cell carcinoma(ESCC) in nonsmokers and nondrinkers; however, HPV increased the risk in smokers.

METHODS

Here we investigated possible interactions between HPV16 serostatus and three susceptibility loci identified in GWASs at apoptosis associated genes with regard to risk of ESCC in a case-control study of 313 patients with ESCC and 314 healthy controls. The loci (CHK2 rs738722, C12orf51 rs2074356, and PLCE1 rs2274223) were genotyped, and the presence or absence of HPV16 in serum was measured by ELISA. Multivariable logistic regression was used to evaluate possible interactions of HPV16 serostatus and the three loci on the risk of ESCC.

RESULTS

A significant interaction was found between HPV16 serology and rs2074356 (P = 0.005, odds ratio [OR] 1.40, 95% confidence interval [CI] 1.11-1.77) or rs2274223 (P < 0.001, OR 1.53, 95% CI 1.23-1.91), but not for rs738722. For rs2074356, risk of ESCC was increased substantially in smokers (P < 0.001, OR 8.25, 95% CI 3.84-17.71) and drinkers (OR4.04, P = 0.001, 95% CI 1.79-9.10) who carried risk alleles (TT or TC genotype) and were HPV16-seropositive. Similar results were observed for rs2274223 in smokers (P < 0.001, OR6.06, 95% CI 2.85-12.88) and drinkers (P < 0.001, OR 5.43, 95% CI 2.51-11.76), but not for rs738722.

CONCLUSION

Consistent with the previous study, loci at rs2074356 and rs2274223 could increase the risk of ESCC, furthermore, there were significant interactions between HPV sero-status and the susceptibility loci on the risk of ESCC. This effect could be modified obviously by smoking and drinking.

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.

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

Background

To date, the association between phospholipase C epsilon 1 (PLCE1) rs2274223 A>G and risk of digestive tract cancer (DTC) remains inconclusive. To derive a more precise estimation of the association, we conducted a meta-analysis on all eligible case–control studies involving 8281 cases and 10,532 controls.

Methods

A comprehensive search was conducted to identify all eligible studies of PLCE1 rs2274223 polymorphism and digestive tract cancer risk. The pooled odds ratio (OR) and the 95% confidence interval (95% CI) were calculated using a fixed or random effect model. Heterogeneity, publication bias, and sensitivity analysis were also explored.

Results

Overall, the PLCE1 rs2274223 A>G polymorphism was associated with risk of DTC in all genetic models (GA vs. AA: OR = 1.21, 95% CI = 1.14–1.29, P<0.001; GG vs. AA: OR = 1.30, 95% CI = 1.06–1.60, P = 0.012; GG/GA vs. AA: OR = 1.20, 95% CI = 1.10–1.32, P<0.001; GG vs. GA/AA: OR = 1.21, 95% CI = 1.01–1.46, P = 0.040). The recessive model did not reach statistically significance when the P values were Bonferroni corrected to 0.0125. In the stratified analysis by cancer type, ethnicity, and source of controls, significantly increased risk was observed for esophagus cancer, Asians in three genetic models (heterozygote comparison, homozygote comparison and dominant model), population-based studies in all genetic models, and for gastric cancer in the heterozygote comparison and dominant model after Bonferroni correction. However, in the subsite of gastric cancer, no significant association was found either in cardia or non-cardia gastric cancer.

Conclusion

Our study indicated that PLCE1 rs2274223 A>G polymorphism was significantly associated with increased risk of DTC, especially among Asian populations. Due to some minor limitations, our findings should be confirmed in further studies.

Xepac protein and IP3/Ca2+ pathway implication during Xenopus laevis vitellogenesis

The objective of this study was to elucidate the signalling pathways initiated by cAMP once inside the Xenopus laevis oocyte, where it triggers and maintains vitellogenin endocytic uptake. Our results showed the presence of Xepac transcripts at all stages of oogenesis and we demonstrated that a cAMP analogue that exclusively activates Xepac, 8-CPT, was able to rescue the endocytic activity in oocytes with uncoupled gap junctions. Inhibition experiments for the IP3/Ca2+ signalling pathway showed either a complete inhibition or a significant reduction of the vitellogenic process. These results were confirmed with the rescue capability of the A-23187 ionophore in those oocyte batches in which the IP3/Ca2+ pathway was inhibited. Taking our findings into account, we propose that the cAMP molecule binds Xepac protein enabling it to activate the IP3/Ca2+ pathway, which is necessary to start and maintain X. laevis vitellogenin uptake.

PLCE1 polymorphism and upper gastrointestinal cancer risk: a meta-analysis

BACKGROUND

In recent years, the PLCE1 rs2274223 polymorphism has been extensively investigated as a potential risk factor for upper gastrointestinal cancers, including squamous cell carcinoma (ESCC) and gastric cancer. However, the results of these studies have been inconsistent.

METHODS

A meta-analysis of 13 case-control studies was performed including more than 11,000 subjects with genotyped PLCE1 rs2274223 polymorphisms. Odds ratios (OR) with 95% confidence intervals (CI) were employed to assess the association of the PLCE1 rs2274223 polymorphism with a susceptibility to ESCC or gastric cancer.

RESULTS

A statistically significant increase in the risk of ESCC was associated with the PLCE1 rs2274223 polymorphism. This included the homozygous genetic model (OR = 1.46), heterozygous genetic model (OR = 1.25) and allelic genetic model (OR = 1.23). Similar results were consistently found for gastric cancer. In a subgroup analysis, the PLCE1 rs2274223 polymorphism was found to be a very sensitive marker for gastric cardia cancer as shown by the homozygous genetic model (OR = 2.23), heterozygous genetic model(OR = 1.59) and allelic genetic model (OR = 1.47). The risk associations of all of the gastric cardia cancer models were statistically significant. In contrast, none of the genetic models for non-cardia gastric cancer were significant.

CONCLUSIONS

In this meta-analysis, the PLCE1 rs2274223 polymorphism was confirmed to have a statistically significant association with an increasing risk of ESCC and gastric cancer. The increase risk was especially observed for gastric cardia cancer.

Overexpression of PLCE1 in Kazakh esophageal squamous cell carcinoma: implications in cancer metastasis and aggressiveness

Three recent large-scale genome-wide association studies (GWAS) in Chinese Han populations have identified an esophageal squamous cell carcinoma (ESCC) susceptibility locus within phospholipase C epsilon 1 (PLCE1) gene, which encodes a phospholipase involved in intracellular signaling. The expressed PLCE1 in ESCC, however, are inconsistent. This study examined PLCE1 expression by immunohistochemistry (IHC) from 110 ethnic Kazakh ESCC patients and 50 from adjacent normal esophageal tissues (NETs). The expressed PLCE1 was localized in cytoplasm, especially in the peripheral layers of cancer cell nests, which was significantly higher in tumors than in NETs (p < 0.001). Increased expression of PLCE1 was correlated with advanced tumor-node-metastasis (TNM) stages (p = 0.015) and lymph node metastasis (p = 0.003) in patients with ESCC. Of the 110 patients, we examined 50 paired ESCC tissues and corresponding NETs by quantitative RT-PCR (polymerase chain reaction) and the mean mRNA level of PLCE1 in ESCC was 1.85-fold higher compared with those in corresponding NETs (p = 0.0012). Meanwhile, 4 of 5 ESCC cell lines also showed elevated expression of PLCE1 mRNA. Furthermore, elevated expression of PLCE1 mRNA in Kazakh ESCC was associated with its immunoreactivity (ρ = 0.297, p = 0.040), lymph node metastasis (p < 0.001), and advanced TNM stages of ESCC (p = 0.013). To our knowledge, this study demonstrates for the first time that PLCE1 overexpression correlates with lymph node metastasis and advanced TNM stages of Kazakh ESCC, implicating a role of PLCE1 in cancer metastasis and aggressiveness in ethnic Kazakh patients with ESCC. Furthermore, the current findings may warrant investigations into whether inhibiting PLCE1 could be a strategy for targeted anticancer therapy particularly for Kazakh ESCC.

Association of genetic polymorphisms at 1q22 but not 10q23 with gastric cancer in a southern Chinese population

OBJECTIVE

Data from a recent genome-wide association studiesy of gastric cancer (GC) and oesophageal squamous cell carcinoma in Chinese living in the Taihang Mountains of north-central China suggest that 1q22 and 10q23 are susceptibility-associated regions for GC. However, this has not been confirmed in southern Chinese populations. The aim of this study was to investigate whether these polymorphisms at 1q22 and 10q23 are associated with the risk of GC in a southern Chinese population.

METHODS

We selected seven top significant associated single nucleotide polymorphisms (SNPs) at 1q22 and 10q23 and conducted a population-based case- control study in a southern Chinese population. Genotypes were determined using MassARRAYTM system (Sequenome, San Diego, CA).

RESULTS

Two SNPs at 1q22, rs4072037 and rs4460629, were significantly associated with a reduced risk of GC, best fitting the dominant genetic model. Logistic regression models adjusted for age and sex showed that rs4072037 AG and GG (OR=0.64, P=0.017, compared with AA) and rs4460629 CT and TT (OR=0.54, P=0.0016, compared with TT) significantly reduced the risk of GC. However, no significant results for the five SNPs at 10q23 were obtained in this study.

CONCLUSION

These outcomes indicate that 1q22 is associated with GC susceptibility in this southern Chinese population, while an association for the locus at 10q23 was not confirmed.

A sequence variant in the phospholipase C epsilon C2 domain is associated with esophageal carcinoma and esophagitis

A single-nucleotide polymorphism (rs2274223: A5780G:His1927Arg) in the phospholipase C epsilon gene (PLCϵ) was recently identified as a susceptibility locus for esophageal cancer in Chinese subjects. To determine the underlying mechanisms of PLCϵ and this SNP in esophageal carcinogenesis, we analyzed PLCϵ genotypes, expression, and their correlation in esophageal cancer cell lines, non-transformed esophageal cells, 58 esophageal squamous cell carcinomas and 10,614 non-cancer subjects from China. We found that the G allele (AG or GG) was associated with increased PLCϵ mRNA and protein expression in esophageal cancer tissues and in esophageal cancer cell lines. G allele was also associated with higher enzyme activity, which might be associated with increased protein expression. Quantitative analysis of the C2 domain sequences revealed that A:G allelic imbalance was strongly linked to esophageal malignancy. Moreover, the analysis of 10,614 non-cancer subjects demonstrated that the G allele was strongly associated with moderate to severe esophagitis in the subjects from the high-incidence areas of China (OR 6.03, 95% CI 1.59-22.9 in high-incidence area vs. OR 0.74, 95% CI 0.33-1.64 in low-incidence area; P = 0.008). In conclusion, the PLCϵ gene, particularly the 5780G allele, might play a pivotal role in esophageal carcinogenesis via upregulating PLCϵ mRNA, protein, and enzyme activity, and augmenting inflammatory process in esophageal epithelium. Thus, 5780G allele may constitute a promising biomarker for esophageal squamous cell carcinoma risk stratification, early detection, and progression prediction.

Esophageal squamous cell carcinoma and gastric cardia adenocarcinoma shared susceptibility locus in PLCE1: a meta-analysis

BACKGROUND AND OBJECTIVE

Two recent genome-wide association studies have identified a shared susceptibility variation PLCE1 rs2274223 for esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinomas (GCA). Subsequent case-control studies have reported this association in other populations. However, the findings were controversial and the effect remains undetermined. Our aim is to provide a precise quantification of the association between PLCE1 rs2274223 variation and the risk of ESCC and GCA.

METHODS

Studies were identified by a literature search in MEDLINE and EMBASE databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association in allele, dominant, recessive, homozygous, and heterozygous models.

RESULTS

Ten articles were identified, including 22156 ESCC cases and 28803 controls, 5197 GCA cases and 17613 controls. Overall, PLCE1 rs2274223 G allele (G vs. A: OR=1.26, 95% CI: 1.15-1.39 for ESCC; OR=1.51, 95% CI: 1.35-1.69 for GCA) and its carrier (GG +AG vs. AA: OR = 1.23; 95% CI =1.02-1.49 for ESCC; OR =1.62; 95% CI =1.15-2.29 for GCA) were significantly associated with the risk of ESCC and GCA. In stratified analysis by ethnicity, significant association of PLCE1 rs2274223 G allele and the risk of ESCC (OR=1.33, 95% CI 1.21-1.45) and GCA (OR =1.56, 95% CI: 1.47-1.64) was observed in Chinese population.

CONCLUSIONS

Our meta-analysis results indicated that PLCE1 rs2274223 G allele significantly contributed to the risk of ESCC and GCA, especially in Chinese population.

Genetic variation in C20orf54, PLCE1 and MUC1 and the risk of upper gastrointestinal cancers in Caucasian populations

Recently, two large genome-wide association studies, conducted in Chinese populations, have reported associations between upper gastrointestinal cancer and the rs2274223, rs13042395 and rs4072037 polymorphisms in PLCE1, C20orf54 and MUC1, respectively. We aimed to determine whether similar associations existed for Caucasian populations. We genotyped two population-based, case-control studies of upper gastrointestinal cancer; the first study included 290 gastric cancer (GC) cases and 376 controls and the second study included 306 GC cases, 107 oesophageal adenocarcinoma cancer cases, 52 oesphageal squamous cell cancer cases and 211 controls. Odds ratios (OR) and 95% confidence intervals (CIs) were computed from logistic models and adjusted for confounding variables. The rs4072037 polymorphism in MUC1 was associated with a reduced risk of GC of intestinal histological type (OR 0.4; 95% CI 0.2-0.9) and a reduced risk of oesophageal squamous cell cancer (OR 0.5; 95% CI 0.2-1.0), but not oesphageal adenocarcinoma. Similarly, rs2274223 in PLCE1 was associated with a reduced risk of oesophageal squamous cell cancer (OR 0.5; 95% CI 0.3-1.0), but not oesphageal adenocarcinoma. We observed no association between rs13042395 in Corf54 and the risk of gastric or oesphageal cancer in either of the two studies. Our findings for rs4072037 and the risk of GC are in agreement with one previous report for a Caucasian population. To the best of our knowledge, this is the first study to report an association between rs2274223 and rs4072037 and the risk of oesophageal squamous cell carcinoma in a Caucasian population.

Phospholipase C isozymes are deregulated in colorectal cancer--insights gained from gene set enrichment analysis of the transcriptome

Colorectal cancer (CRC) is one of the most common cancer types in developed countries. To identify molecular networks and biological processes that are deregulated in CRC compared to normal colonic mucosa, we applied Gene Set Enrichment Analysis to two independent transcriptome datasets, including a total of 137 CRC and ten normal colonic mucosa samples. Eighty-two gene sets as described by the Kyoto Encyclopedia of Genes and Genomes database had significantly altered gene expression in both datasets. These included networks associated with cell division, DNA maintenance, and metabolism. Among signaling pathways with known changes in key genes, the “Phosphatidylinositol signaling network”, comprising part of the PI3K pathway, was found deregulated. The downregulated genes in this pathway included several members of the Phospholipase C protein family, and the reduced expression of two of these, PLCD1 and PLCE1, were successfully validated in CRC biopsies (n = 70) and cell lines (n = 19) by quantitative analyses. The repression of both genes was found associated with KRAS mutations (P = 0.005 and 0.006, respectively), and we observed that microsatellite stable carcinomas with reduced PLCD1 expression more frequently had TP53 mutations (P = 0.002). Promoter methylation analyses of PLCD1 and PLCE1 performed in cell lines and tumor biopsies revealed that methylation of PLCD1 can contribute to reduced expression in 40% of the microsatellite instable carcinomas. In conclusion, we have identified significantly deregulated pathways in CRC, and validated repression of PLCD1 and PLCE1 expression. This illustrates that the GSEA approach may guide discovery of novel biomarkers in cancer.

Association between novel PLCE1 variants identified in published esophageal cancer genome-wide association studies and risk of squamous cell carcinoma of the head and neck

BACKGROUND

Phospholipase C epsilon 1 (PLCE1) (an effector of Ras) belonging to the phospholipase family plays crucial roles in carcinogenesis and progression of several cancers, including squamous cell carcinoma of the head and neck (SCCHN). A single nucleotide polymorphism (SNP, rs2274223) in PLCE1 has been identified as a novel susceptibility locus in genome-wide association studies (GWAS) of esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA) that share similar risk factors with SCCHN. Therefore, we investigated the association between potentially functional SNPs in PLCE1 and susceptibility to SCCHN.

METHODS

We genotyped three potentially functional SNPs (rs2274223A/G, rs3203713A/G and rs11599672T/G) of PLCE1 in 1,098 SCCHN patients and 1,090 controls matched by age and sex in a non-Hispanic white population.

RESULTS

Although none of three SNPs was alone significantly associated with overall risk of SCCHN, their combined effects of risk alleles (rs2274223G, rs3203713G and rs11599672G) were found to be associated with risk of SCCHN in a locus-dose effect manner (Ptrend=0.046), particularly for non-oropharyngeal tumors (Ptrend=0.017); specifically, rs2274223 was associated with a significantly increased risk (AG vs. AA: adjusted OR=1.29, 95% CI=1.01-1.64; AG/GG vs. AA: adjusted OR=1.30, 95% CI=1.03-1.64), while rs11599672 was associated with a significantly decreased risk (GG vs. TT: adjusted OR=0.54, 95% CI=0.34-0.86; TG/GG vs. TT: adjusted OR=0.76, 95% CI=0.61-0.95).

CONCLUSIONS

Our findings suggest that PLCE1 variants may have an effect on risk of SCCHN associated with tobacco and alcohol exposure, particularly for those tumors arising at non-oropharyngeal sites. These findings, although need to be validated by larger studies, are consistent with those in esophageal and gastric cancers.

Genetic variants at 1q22 and 10q23 reproducibly associated with gastric cancer susceptibility in a Chinese population

Two recent genome-wide association studies reported significant associations of genetic variants at 1q22, 10q23 and 20p13 with gastric cancer (GC) risk in Chinese populations. However, these findings have not been confirmed in other independent studies. Here, we performed an independent case-control study in a Chinese population by genotyping three loci (rs4072037A>G at 1q22, rs2274223A>G at 10q23 and rs13042395C>T at 20p13) in 1681 GC cases and 1858 controls. We found that rs4072037 at 1q22 and rs2274223 at 10q23 were significantly associated with risk of GC with per allele odds ratio (OR) of 0.72 [95% confidence interval (CI): 0.63-0.81; P = 2.98 × 10(-7)] and 1.42 (95% CI: 1.27-1.58; P = 9.68 × 10(-10)), respectively. The association was more prominent for rs2274223 in female (OR = 1.86, 95% CI: 1.49-2.32) and gastric cardia adenocarcinoma (GCA) (OR = 1.71, 95% CI: 1.49-1.95). Furthermore, we combined the two single-nucleotide polymorphisms to evaluate the joint effect and found that the GC risk significantly increased with the number of risk allele increasing with a trend P value of 6.66 × 10(-16), and individuals with four risk alleles had a 3.28-fold (95% CI: 1.75-6.13) risk of GC compared with those having no risk alleles. However, no significant association was detected between rs13042395 at 20p13 and GC risk (OR = 1.04, 95% CI: 0.94-1.15; P = 0.452). In conclusion, our results indicate that genetic variants at 1q22 and 10q23 but not 20p13 may serve as candidate markers for GC susceptibility in the Chinese population.

A shared susceptibility locus in PLCE1 at 10q23 for gastric adenocarcinoma and esophageal squamous cell carcinoma

We conducted a genome-wide association study of gastric cancer (GC) and esophageal squamous cell carcinoma (ESCC) in ethnic Chinese subjects in which we genotyped 551,152 single nucleotide polymorphisms (SNPs). We report a combined analysis of 2,240 GC cases, 2,115 ESCC cases, and 3,302 controls drawn from five studies. In logistic regression models adjusted for age, sex, and study, multiple variants at 10q23 had genome-wide significance for GC and ESCC independently. A notable signal was rs2274223, a nonsynonymous SNP located in PLCE1, for GC (P=8.40×10⁻⁹; per allele odds ratio (OR) = 1.31) and ESCC (P=3.85×10⁻⁹; OR = 1.34). The association with GC differed by anatomic subsite. For tumors located in the cardia the association was stronger (P=4.19 × 10⁻¹⁵; OR= 1.57) and for those located in the noncardia stomach it was absent (P=0.44; OR=1.05). Our findings at 10q23 could provide insight into the high incidence rates of both cancers in China.

Genome-wide association study of esophageal squamous cell carcinoma in Chinese subjects identifies susceptibility loci at PLCE1 and C20orf54

We performed a genome-wide association study of esophageal squamous cell carcinoma (ESCC) by genotyping 1,077 individuals with ESCC and 1,733 control subjects of Chinese Han descent. We selected 18 promising SNPs for replication in an additional 7,673 cases of ESCC and 11,013 control subjects of Chinese Han descent and 303 cases of ESCC and 537 control subjects of Chinese Uygur-Kazakh descent. We identified two previously unknown susceptibility loci for ESCC: PLCE1 at 10q23 (P(Han combined for ESCC) = 7.46 x 10(-56), odds ratio (OR) = 1.43; P(Uygur-Kazakh for ESCC) = 5.70 x 10(-4), OR = 1.53) and C20orf54 at 20p13 (P(Han combined for ESCC) = 1.21 x 10(-11), OR = 0.86; P(Uygur-Kazakh for ESCC) = 7.88 x 10(-3), OR = 0.66). We also confirmed association in 2,766 cases of gastric cardia adenocarcinoma cases and the same 11,013 control subjects (PLCE1, P(Han for GCA) = 1.74 x 10(-39), OR = 1.55 and C20orf54, P(Han for GCA) = 3.02 x 10(-3), OR = 0.91). PLCE1 and C20orf54 have important biological implications for both ESCC and GCA. PLCE1 might regulate cell growth, differentiation, apoptosis and angiogenesis. C20orf54 is responsible for transporting riboflavin, and deficiency of riboflavin has been documented as a risk factor for ESCC and GCA.