Associations of PI3KR1 and mTOR polymorphisms with esophageal squamous cell carcinoma risk and gene-environment interactions in Eastern Chinese populations

Association of Genetic Variations in The PIK3-AKT-mTOR Pathway with Endometriosis Susceptibility: A Preliminary Case-Control Study

BACKGROUND

Endometriosis is a complex, heterogeneous disease with several genetic and non-genetic pathogenic factors. The phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway may influence both progression and different stages of endometriosis. This study aims to investigate the effects of the PIK3CA, AKT1, and mTOR single nucleotide polymorphisms (SNP) with endometriosis risk in an Iranian cohort.

MATERIALS AND METHODS

In this case-control study, samples from 127 patients and 125 controls were examined using allelespecific polymerase chain reaction (AS-PCR) polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

The PIK3CA rs2230461 and AKT1 rs1130233 had a more than 2.5-fold significant increase in disease risk in a homozygous mutation [95% confidence interval (CI): 1.119 -5.985; 95% CI: 1.093-7.535, respectively]. However, the risk was reduced by half or less than half in carriers of the mutant alleles for mTOR rs2295080 (95% CI: 0.108- 0.927, P=0.036). We confirmed that moderate/severe endometriosis was approximately five times more common in patients with the PIK3CA mutant genotype [odds ratio (OR): 4.800, 95% CI: 2.171-10.611, P<0.001], and over two times more frequent in patients with the AKT1 mutant variant (OR: 2.674, 95% CI: 1.261-5.670, P=0.010). The mutant allele for mTOR rs2295080 was more frequent in patients with stages I and II endometriosis (P=0.022).

CONCLUSION

The results show that PIK3CA rs2230461 and AKT1 rs1130233 SNPs are risk factors for endometriosis and the mTOR rs2295080 gene polymorphism is a protective factor for the development of endometriosis in an Iranian cohort. The PIK3CA rs2230461, AKT1 rs1130233, and mTOR rs2295080 gene polymorphisms should be further investigated as potential candidate SNPs for predicting endometriosis susceptibility.

MTOR gene variants are associated with severe COVID-19 outcomes: A multicenter study

BACKGROUND

The worst outcomes linked to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been attributed to the cytokine storm, which contributes significantly to the immunopathogenesis of the disease. The mammalian target of rapamycin (mTOR) pathway is essential for orchestrating innate immune cell defense including cytokine production and is dysregulated in severe Coronavirus Disease 2019 (COVID-19) individuals. The individual genetic background might play a role in the exacerbated immune response.

OBJECTIVE

In this study, we aimed to investigate the association between MTOR genetic variants and COVID-19 outcomes.

METHODS

This study enrolled groups of individuals with severe (n = 285) and mild (n = 207) COVID-19 from Brazilian states. The MTOR variants, rs1057079 and rs2536, were genotyped. A logistic regression analysis and Kaplan-Meier survival curves were performed. We applied a genotyping risk score to estimate the cumulative contribution of the risk alleles. Tumor necrosis factor (TNF) and interleukin-6 (IL-6) plasma levels were also measured.

RESULTS

The T allele of the MTOR rs1057079 variant was associated with a higher likelihood of developing the most severe form of COVID-19. In addition, higher levels of IL-6 and COVID-19 death was linked to the T allele of the rs2536 variant. These variants exhibited a cumulative risk when inherited collectively.

CONCLUSIONS

These results show a potential pathogenetic role of MTOR gene variants and may be useful for predicting severe outcomes following COVID-19 infection, resulting in a more effective allocation of health resources.

Overview of Risk Factors for Esophageal Squamous Cell Carcinoma in China

(1) Background: China has the highest esophageal squamous cell carcinoma (ESCC) incidence areas in the world, with some areas of incidence over 100 per 100,000. Despite extensive public health efforts, its etiology is still poorly understood. This study aims to review and summarize past research into potential etiologic factors for ESCC in China. (2) Methods: Relevant observational and intervention studies were systematically extracted from four databases using key terms, reviewed using Rayyan software, and summarized into Excel tables. (3) Results: Among the 207 studies included in this review, 129 studies were focused on genetic etiologic factors, followed by 22 studies focused on dietary-related factors, 19 studies focused on HPV-related factors, and 37 studies focused on other factors. (4) Conclusions: ESCC in China involves a variety of factors including genetic variations, gene-environment interactions, dietary factors like alcohol, tobacco use, pickled vegetables, and salted meat, dietary behavior such as hot food/drink consumption, infections like HPV, poor oral health, gastric atrophy, and socioeconomic factors. Public health measures should prioritize genetic screening for relevant polymorphisms, conduct comprehensive investigations into environmental, dietary, and HPV influences, enhance oral health education, and consider socioeconomic factors overall as integral strategies to reduce ESCC in high-risk areas of China.

Rare variants confer shared susceptibility to gastrointestinal tract cancer risk

Background

Cancers arising within the gastrointestinal tract are complex disorders involving genetic events that cause the conversion of normal tissue to premalignant lesions and malignancy. Shared genetic features are reported in epithelial-based gastrointestinal cancers which indicate common susceptibility among this group of malignancies. In addition, the contribution of rare variants may constitute parts of genetic susceptibility.

Methods

A cross-cancer analysis of 38,171 shared rare genetic variants from genome-wide association assays was conducted, which included data from 3,194 cases and 1,455 controls across three cancer sites (esophageal, gastric and colorectal). The SNP-level association was performed by multivariate logistic regression analyses for single cancer, followed by association analysis for SubSETs (ASSET) to adjust the bias of overlapping controls. Gene-level analyses were conducted by SKAT-O, with multiple comparison adjustments by false discovery rate (FDR). Based on the significant genes indicated by SKATO analysis, pathways analysis was conducted using Gene Ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome databases.

Results

Meta-analysis in three gastrointestinal (GI) cancers identified 13 novel susceptibility loci that reached genome-wide significance (P _ASSET< 5×10^-8). SKAT-O analysis revealed EXOC6, LRP5L and MIR1263/LINC01324 to be significant genes shared by GI cancers (P _adj<0.05, P _FDR<0.05). Furthermore, GO pathway analysis identified significant enrichment of synaptic transmission and neuron development pathways shared by all three cancer types.

Conclusion

Rare variants and the corresponding genes potentially contribute to shared susceptibility in different GI cancer types. The discovery of these novel variants and genes offers new insights for the carcinogenic mechanisms and missing heritability of GI cancers.

PIK3CB promotes oesophageal cancer proliferation through the PI3K/AKT/mTOR signalling axis

PIK3CB is abnormally expressed in various carcinomas and affects the proliferation, invasion and drug resistance of cancer cells. However, its role in oesophageal squamous cell carcinoma (ESCC) is still unclear. In this study, PIK3CB was found to be highly expressed in ESCC tissues and cells and positively correlated with the poor prognosis of ESCC. Silencing PIK3CB inhibited the proliferation of ESCC cells, arrested the cell cycle, and promoted apoptosis. Mechanistic studies showed that the tumour-promoting effect of PIK3CB was achieved through PI3K/AKT/mTOR signalling pathway activation. Moreover, the high PIK3CB expression level in ESCC may be closely associated with the hypomethylation status of the gene promoter. In conclusion, PIK3CB promotes ESCC by activating the PI3K/AKT/mTOR signalling axis. PIK3CB may be a potential target in ESCC.

PI3K/Akt/mTOR Signaling Pathway: Role in Esophageal Squamous Cell Carcinoma, Regulatory Mechanisms and Opportunities for Targeted Therapy

Esophageal squamous cell carcinoma (ESCC), is the most common type of esophageal cancer worldwide, mainly occurring in the Asian esophageal cancer belt, including northern China, Iran, and parts of Africa. Phosphatidlinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway is one of the most important cellular signaling pathways, which plays a crucial role in the regulation of cell growth, differentiation, migration, metabolism and proliferation. In addition, mutations in some molecules of PI3K/Akt/mTOR pathway are closely associated with survival and prognosis in ESCC patients. A large number of studies have found that there are many molecules in ESCC that can regulate the PI3K/Akt/mTOR pathway. Overexpression of these molecules often causes aberrant activation of PI3K/Akt/mTOR pathway. Currently, several effective PI3K/Akt/mTOR pathway inhibitors have been developed, which can play anticancer roles either alone or in combination with other inhibitors. This review mainly introduces the general situation of ESCC, the composition and function of PI3K/Akt/mTOR pathway, and regulatory factors that interact with PI3K/Akt/mTOR signaling pathway. Meanwhile, mutations and inhibitors of PI3K/Akt/mTOR pathway in ESCC are also elucidated.

Associations of Genetic Polymorphisms of mTOR rs2295080 T/G and rs1883965 G/A with Susceptibility of Urinary System Cancers

Background. Genetic polymorphisms in mammalian target of rapamycin (mTOR) signaling axis can influence the susceptibility of cancer. The relationship between mTOR gene variants rs2295080 T/G and rs1883965 G/A and the risk of cancer remains inconsistent. The present study is aimed at comprehensively investigating the association between mTOR polymorphisms and susceptibility to cancer. Methods. We conducted a comprehensive assessment using odds ratios (ORs), corresponding 95% confidence intervals (CIs), and in silico tools to evaluate the effect of mTOR variations. Immunohistochemical staining (IHS) and GSEA analysis were used to investigate the expression of mTOR in urinary system cancer. Results. The pooled analysis involved 22 case-control studies including 14,747 cancer patients and 16,399 controls. The rs2295080 T/G polymorphism was associated with the risk of cancer (G-allele versus T-allele, $\text{OR}=0.89$ , $95\%\text{CI}=0.80$ –0.98, $P=0.023$ ; GT versus TT, $\text{OR}=0.88$ , $95\%\text{CI}=0.81$ –0.96, $P=0.004$ ; GG+GT versus TT, $\text{OR}=0.87$ , $95\%\text{CI}=0.78$ –0.96, $P=0.008$ ), especially for cancers of the urinary system, breast, and blood. Variation rs1883965 G/A was associated with cancer susceptibility, especially for digestive cancer. IHS analysis showed that mTOR was upregulated in prostate and bladder cancer. GSEA revealed that the insulin signaling pathway, lysine degradation pathway, and mTOR signaling pathway were enriched in the high mTOR expression group. Conclusions. The mTOR rs2295080 T/G polymorphism may be associated with susceptibility of urinary cancer. The expression of mTOR is positively correlated with tumor malignancy in prostate cancer.

Polymorphisms in the mTOR-PI3K-Akt pathway, energy balance-related exposures and colorectal cancer risk in the Netherlands Cohort Study

BACKGROUND

The mTOR-PI3K-Akt pathway influences cell metabolism and (malignant) cell growth. We generated sex-specific polygenic risk scores capturing natural variation in 7 out of 10 top-ranked genes in this pathway. We studied the scores directly and in interaction with energy balance-related factors (body mass index (BMI), trouser/skirt size, height, physical activity, and early life energy restriction) in relation to colorectal cancer (CRC) risk in the Netherlands Cohort Study (NLCS) (n=120,852). The NLCS has a case-cohort design and 20.3 years of follow-up. Participants completed a baseline questionnaire on diet and cancer in 1986 when 55-69 years old. ~75% of the cohort returned toenail clippings used for DNA isolation and genotyping (n subcohort=3,793, n cases=3,464). To generate the scores, the dataset was split in two and risk alleles were defined and weighted based on sex-specific associations with CRC risk in the other dataset half, because there were no SNPs in the top-ranked genes associated with CRC risk in previous genome-wide association studies at a significance level p<1*10^-5.

RESULTS

Cox regression analyses showed positive associations between the sex-specific polygenic risk scores and colon but not rectal cancer risk in men and women, with hazard ratios for continuously modeled scores close to 1.10. There was no modifying effect observed of the scores on associations between the energy balance-related factors and CRC risk. However, BMI (in men), non-occupational physical activity (in women), and height (in men and women) were associated with the risk of CRC, in particular (proximal and distal) colon cancer, in the direction as expected in the lower tertiles of the sex-specific polygenic risk scores.

CONCLUSIONS

Current data suggest that the mTOR-PI3K-Akt pathway may be involved in colon cancer development. This study thereby sheds more light on colon cancer etiology through use of genetic variation in the mTOR-PI3K-Akt pathway.

Meta-analysis of the association between mTORC1-related genes polymorphisms and cancer risk

BACKGROUND

mTOR, mLST8 and RAPTOR are the core components of mTORC1, which has been found to be closely related to tumorigenesis. Currently, multiple single nucleotide polymorphisms (SNPs) in mTOR gene (rs2295080, rs17036508 and rs1034528), mLST8 gene (rs3160 and rs26865) and RPTOR gene (rs1062935, rs3751932, rs3751834, rs12602885) have been extensively studied for their associations with cancer risk. However, the results remained inconclusive and conflicting. Therefore, we here performed a meta-analysis of all available studies to investigate the association between these SNPs and cancer risk.

METHODS

Up to April 2021, 25 related publications were retrieved and included in this meta-analysis. The odds ratios (ORs) and 95% confidence intervals (CIs) calculated by fixed or random effects models were applied to assess the strength of association. Trial Sequential Analysis (TSA) was conducted to weaken the random error and enhance the reliability of evidence.

RESULTS

After Bonferroni correction, it was revealed that rs3160, rs26865, rs1062935, rs3751932, rs3751834 and rs10602885 were not associated with cancer risk. However, rs17036508 and rs1034528 showed significant association with total cancer risk. A significant association was also found between rs2295080 and total cancer risk, and stratified analysis by cancer type suggested that rs2295080 was specifically associated with acute lymphoblastic leukemia risk, prostate cancer risk, and breast cancer risk.

CONCLUSIONS

The present meta-analysis suggested that the rs2295080, rs17036508 and rs1034528 polymorphisms in mTOR gene may be the susceptive factors for cancer development, while the target genetic polymorphisms in mLST8 gene or RPTOR gene may not be associated with cancer risk. However, these findings remain to be confirmed or further reinforced in large and well-designed studies in different ethnic populations.

Distribution and susceptibility of ERCC1/XPF gene polymorphisms in Han and Uygur women with breast cancer in Xinjiang, China

This study aimed to explore the roles of ERCC1/XPF gene polymorphisms in the occurrence of breast cancer in the Uygur and Han ethnic groups in Xinjiang, China. Single nucleotide polymorphisms (SNPs) were detected by TaqMan real-time PCR. The rs11615 G>A and rs2276466 C>G variant frequencies were higher in Uygur patients with breast cancer than in Han patients, while the frequency of rs2298881 C>A was higher in Han patients. We found that rs2298881 C>A (CA vs. CC: OR = 0.35, 95% CI = 0.20-0.60; AA vs. CC: OR = 0.13, 95% CI = 0.04-0.34; CA + AA vs. CC: OR = 0.33, 95% CI = 0.18-0.51; AA vs. CA + CC: OR = 0.24, 95% CI = 0.08-0.62; CA vs. AA + CC: OR = 0.49, 95% CI = 0.29-0.82) was associated with a reduced breast cancer risk and rs3212986 C>A (AA vs. CC: OR = 4.80, 95% CI = 1.79-15.29,; CA+AA vs. CC: OR = 1.71, 95% CI = 1.06-2.77; AA vs. CA+CC: OR = 4.12, 95% CI =1.58-12.89) and rs11615 G > A (AA vs. GG: OR = 3.49, 95% CI =1.54-8.55; GA + AA vs. GG: OR = 1.98, 95% CI = 1.21-3.27; AA vs. GA+GG: OR = 2.87, 95% CI = 1.30-6.85) were associated with an elevated breast cancer risk among Uygur individuals. In addition, Uygur patients with breast cancer with 2-3 combined risk genotypes of ERCC1 had a higher risk than patients with 0-1 risk genotypes (OR = 2.91; 95% CI = 1.54-5.71, p = 0.001). However, we failed to detect a statistically significant association between ERCC1/XPF polymorphisms and breast cancer risk in five genetic models among Han individuals. Our results showed that ERCC1/XPF gene polymorphisms predispose Uygur individuals to breast cancer; this finding should be verified by further large-scale analyses.

Impact of mTOR gene polymorphisms and gene-tea interaction on susceptibility to tuberculosis

BACKGROUND

mTOR gene is a key component of the PI3K/Akt/mTOR signaling pathway, and its dysregulation is associated with various diseases. Several studies have demonstrated that tea drinking is a protective factor against tuberculosis (TB). This study was designed to explore five single nucleotide polymorphisms (SNPs) of mTOR in the Han population of China to determine how their interactions with tea drinking affect susceptibility to TB.

AIM

To investigate if the polymorphisms of mTOR gene and the gene-tea interaction are associated with susceptibility to TB.

METHODS

In this case-control study, 503 patients with TB and 494 healthy controls were enrolled by a stratified sampling method. The cases were newly registered TB patients from the county-level centers for disease control and prevention, and the healthy controls were permanent residents from Xin’ansi Community, Changsha city. Demographic data and environmental exposure information including tea drinking were obtained from the study participants. We genotyped five potentially functional SNP sites (rs2295080, rs2024627, rs1057079, rs12137958, and rs7525957) of mTOR gene and assessed their associations with the risk of TB using logistic regression analysis, and marginal structural linear odds models were used to estimate the gene-environment interactions.

RESULTS

The frequencies of four SNPs (rs2295080, rs2024627, rs1057079, and rs7525957) were found to be associated with susceptibility to TB (P < 0.05). Genotypes GT (OR 1.334), GG (OR 2.224), and GT + GG (OR 1.403) at rs2295080; genotypes CT (OR 1.562) and CT + TT (OR 1.578) at rs2024627, genotypes CT (OR 1.597), CC (OR 2.858), and CT + CC (OR 1.682) at rs1057079; and genotypes CT (OR 1.559) and CT + CC (OR 1.568) at rs7525957 of mTOR gene were significantly more prevalent in TB patients than in healthy controls. The relative excess risk of interaction between the four SNPs (rs2295080, rs2024627, rs1057079, and rs7525957) of mTOR genes and tea drinking were found to be -1.5187 (95%CI: -1.9826, -1.0547, P < 0.05), -1.8270 (95%CI: -2.3587, -1.2952, P < 0.05), -2.3246 (95%CI: -2.9417, -1.7076, P < 0.05) and -0.4235 (95%CI: -0.7756, -0.0714, P < 0.05), respectively, which suggest negative interactions.

CONCLUSION

The polymorphisms of mTOR (rs2295080, rs2024627, rs1057079, and rs7525957) are associated with susceptibility to TB, and there is a negative interaction between each of the four SNPs and tea drinking.

Comprehensive analysis of the effect of rs2295080 and rs2536 polymorphisms within the mTOR gene on cancer risk

There is still no conclusion on the potential effect of the rs2295080 and rs2536 polymorphisms of mTOR (mammalian target of rapamycin) gene on different cancers. Herein, we performed a comprehensive assessment using pooled analysis, FPRP (false-positive report probability), TSA (trial sequential analysis), and eQTL (expression quantitative trait loci) analysis. Eighteen high-quality articles from China were enrolled. The pooled analysis of rs2295080 with 9502 cases and 10,965 controls showed a decreased risk of urinary system tumors and specific prostate cancers [TG vs. TT, TG+GG vs. TT and G vs. T; P<0.05, OR (odds ratio) <1]. FPRP and TSA data further confirmed these results. There was an increased risk of leukemia [G vs. T, GG vs. TT, and GG vs. TT+TG genotypes; P<0.05, OR>1]. The eQTL data showed a potential correlation between the rs2295080 and mTOR expression in whole blood samples. Nevertheless, FPRP and TSA data suggested that more evidence is required to confirm the potential role of rs2295080 in leukemia risk. The pooled analysis of rs2536 (6653 cases and 7025 controls) showed a significant association in the subgroup of "population-based" control source via the allele, heterozygote, dominant, and carrier comparisons (P<0.05, OR>1). In conclusion, the TG genotype of mTOR rs2295080 may be linked to reduced susceptibility to urinary system tumors or specific prostate cancers in Chinese patients. The currently data do not strongly support a role of rs2295080 in leukemia susceptibility. Large sample sizes are needed to confirm the potential role of rs2536 in more types of cancer.

TP53 Arg72Pro polymorphism and neuroblastoma susceptibility in eastern Chinese children: a three-center case-control study

TP53 is a tumor suppressor gene that regulates cell growth, apoptosis and DNA repair. Previous studies have reported the contribution of TP53 Arg72Pro (rs1042522 C>G) polymorphism to pathogenesis of multiple tumors. Hence, we evaluated the association between this polymorphism and neuroblastoma susceptibility in eastern Chinese children. The Taqman genotyping assay was performed in 373 patients and 762 controls. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of the association. No significant association was found between the TP53 gene rs1042522 C>G polymorphism and neuroblastoma susceptibility in the overall analysis (CG vs. CC: adjusted OR = 0.92, 95% CI = 0.70-1.22, P=0.567; GG vs. CC: adjusted OR = 0.99, 95% CI = 0.69-1.42, P=0.947; CG/GG vs. CC: adjusted OR = 0.94, 95% CI = 0.72-1.23, P=0.639; or GG vs. CC/CG: adjusted OR = 1.04, 95% CI = 0.75-1.43, P=0.814) and stratified analysis by age, gender, sites of origin, and clinical stages. The TP53 gene rs1042522 C>G polymorphism may not be a risk factor for neuroblastoma in eastern Chinese children. Future studies are needed to confirm this negative result and to reveal additional functional TP53 variants predisposing to neuroblastoma.

Immunosignature Screening for Multiple Cancer Subtypes Based on Expression Rule

Liquid biopsy (i.e., fluid biopsy) involves a series of clinical examination approaches. Monitoring of cancer immunological status by the “immunosignature” of patients presents a novel method for tumor-associated liquid biopsy. The major work content and the core technological difficulties for the monitoring of cancer immunosignature are the recognition of cancer-related immune-activating antigens by high-throughput screening approaches. Currently, one key task of immunosignature-based liquid biopsy is the qualitative and quantitative identification of typical tumor-specific antigens. In this study, we reused two sets of peptide microarray data that detected the expression level of potential antigenic peptides derived from tumor tissues to avoid the detection differences induced by chip platforms. Several machine learning algorithms were applied on these two sets. First, the Monte Carlo Feature Selection (MCFS) method was used to analyze features in two sets. A feature list was obtained according to the MCFS results on each set. Second, incremental feature selection method incorporating one classification algorithm (support vector machine or random forest) followed to extract optimal features and construct optimal classifiers. On the other hand, the repeated incremental pruning to produce error reduction, a rule learning algorithm, was applied on key features yielded by the MCFS method to extract quantitative rules for accurate cancer immune monitoring and pathologic diagnosis. Finally, obtained key features and quantitative rules were extensively analyzed.

Association of miR-34b/c rs4938723 and TP53 Arg72Pro Polymorphisms with Neuroblastoma Susceptibility: Evidence from Seven Centers

Neuroblastoma is a pediatric malignancy arising from the developing peripheral nervous system. p53 and downstream effector miR-34b/c have critical tumor suppressing functions. TP53 Arg72Pro (rs1042522 C > G) and miR-34b/c rs4938723 (T > C) polymorphisms have been known to modify cancer susceptibility. This study was performed to validate the association of these two polymorphisms and neuroblastoma risk with 819 cases and 1780 controls. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to assess the strength of the associations. False positive report possibility analysis was adopted to dissect out real significant associations from chance findings. We found that both TP53 Arg72Pro (CG/GG vs. CC: adjusted OR = 0.82, 95% CI = 0.69-0.98) and miR-34b/c rs4938723 (TC/CC vs. TT: adjusted OR = 0.64, 95% CI = 0.54-0.75) were associated with decreased neuroblastoma susceptibility. Stratify analyses further confirmed the protective effect among some subgroups. Moreover, subjects with variant alleles of both polymorphisms were associated with more significantly decreased neuroblastoma risk (CG/TC vs. CC/TT: adjusted OR = 0.38, 95% CI = 0.28-0.50; GG/TC vs. CC/TT: adjusted OR = 0.43, 95% CI = 0.30-0.63) than those carrying variant allele of either one polymorphism (CC/TC vs. CC/TT: adjusted OR = 0.51, 95% CI = 0.37-0.69; CG/TT vs. CC/TT: adjusted OR = 0.71, 95% CI = 0.55-0.92), suggesting cumulative effects of the polymorphisms. False positive report possibility analysis further verified that our findings are noteworthy. Overall, we confirmed that miR-34b/c rs4938723 and TP53 Arg72Pro conferred decreased neuroblastoma risk and two polymorphisms exerted stronger protective effects against neuroblastoma than either one alone.

Breast Cancer Risk-Associated SNPs in the mTOR Promoter Form De Novo KLF5- and ZEB1-Binding Sites that Influence the Cellular Response to Paclitaxel

ZEB1 (a positive enhancer) and KLF5 (a negative silencer) affect transcription factors and play inherently conserved roles in tumorigenesis and multidrug resistance. In humans, the rs2295080T-allele at the mTOR promoter locus has been associated with human cancer risk; however, the 63 bp spacing of another SNP rs2295079 has not been identified. Here, we discovered, for the first time, that rs2295079 (-78C/G) and rs2295080 (-141G/T) formed linkage haplotypes, with Ht1 (-78C/-141G) and Ht2 (-78G/-141T) being dominant, which were associated with distinct susceptibility to breast cancer, response to paclitaxel, and clinical outcomes in breast cancer. At the cellular level, compared with Ht1, Ht2 exhibits a much stronger effect on promoting mTOR expression, leading to enhanced tumor cell growth and strengthened resistance to PTX treatment. Mechanistically, the -141T allele of Ht2 creates a novel ZEB1-binding site; meanwhile, the -78C allele of Ht1 exists as an emerging KLF5-binding site, which synergistically induces promote/inhibit mTOR expression, cell proliferation, and excretion of cytotoxic drugs through the ZEB1/KLF5-mTOR-CCND1/ABCB1 cascade, thereby affecting the response to paclitaxel treatment in vivo and in vitro. Our results suggest the existence of a ZEB1/KLF5-mTOR-CCND1/ABCB1 axis in human cells that could be involved in paclitaxel response pathways and functionally regulate interindividualized breast cancer susceptibility and prognosis. IMPLICATIONS: This study highlights the function of haplotypes of mTOR -78C/-141G and -78G/-141T, in affecting breast cancer susceptibility and paclitaxel response regulated by ZEB1/KLF5-mTOR-CCND1/ABCB1 axis.

ALC1 knockdown enhances cisplatin cytotoxicity of esophageal squamous cell carcinoma cells by inhibition of glycolysis through PI3K/Akt pathway

AIMS

Amplified in liver cancer 1 gene (ALC1), a recently identified oncogene, was reported to be overexpressed in esophageal cancer cell lines and identified as a target oncogene in esophageal cancer pathogenesis. However, little literature is available to illustrate its significance in cisplatin resistance of esophageal squamous cell carcinoma (ESCC) cells. The aim of the current study was to investigate the effect of ALC1 on cisplatin cytotoxicity of ESCC cells and to study the potential mechanisms.

MAIN METHODS

ALC1 at mRNA and protein levels were detected by qRT-PCR and western blot, respectively. Cell viability was evaluated using CCK-8 assay. Apoptosis was assessed using caspase-3/7 activity assay and flow cytometry analysis. Glycolysis level was evaluated by measuring glucose consumption and lactate production. The protein levels of p-protein kinase B (Akt) and Akt were determined by western blot.

KEY FINDINGS

ALC1 was highly expressed in ESCC cells compared with human normal esophageal epithelial Het-1A cells. ALC1 knockdown suppressed the viability, induced apoptosis and enhanced cisplatin cytotoxicity in ESCC cells. In addition, ALC1 knockdown inhibited glycolysis and inactivated the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in ESCC cells. Mechanistically, activation of the PI3K/Akt pathway by 740Y-P blocked the effects of ALC1 knockdown on cisplatin cytotoxicity and glycolysis in ESCC cells. In contrast, inhibition of the PI3K/Akt pathway by LY294002 or glycolysis by 2-deoxyglucose resisted the effect of ALC1 overexpression on cisplatin cytotoxicity in ESCC cells.

SIGNIFICANCE

ALC1 knockdown enhanced cisplatin cytotoxicity of ESCC cells by inhibition of glycolysis through inactivation of the PI3K/Akt pathway.

LMO1 Gene Polymorphisms Reduce Neuroblastoma Risk in Eastern Chinese Children: A Three-Center Case-Control Study

Background: Neuroblastoma, a neuroendocrine tumor, stems from the developing sympathetic nervous system. Previous genome-wide association studies (GWASs) have discovered a number of neuroblastoma susceptibility genes in Caucasians including LIM domain only 1 (LMO1). Objective: We conducted a three-center case-control study including 313 cases and 716 controls with the purpose to evaluate the association between five GWAS-identified LMO1 variants (rs110419 A>G, rs4758051 G>A, rs10840002 A>G, rs204938 A>G, and rs2168101 G>T) and neuroblastoma susceptibility in eastern Chinese children. Methods: Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the associations. False positive report possibility (FPRP) analysis was performed to check whether significant results were noteworthy. Results: Significant associations with neuroblastoma risk were found for four (rs110419, rs4758051, rs10840002, and rs2168101) out of the five polymorphisms. Combined analysis demonstrated that carriers of 4-5 protective genotypes had a significantly decreased risk of neuroblastoma in comparison those with 0-3 protective genotypes (adjusted OR = 0.51, 95% CI = 0.39-0.68, P < 0.0001). Haplotype analysis of the five SNPs yield four significant haplotypes associated with neuroblastoma susceptibility. Conclusion: In conclusion, we confirmed LMO1 polymorphisms may reduce neuroblastoma risk in eastern Chinese populations.

Association between NER Pathway Gene Polymorphisms and Wilms Tumor Risk

Nucleotide excision repair (NER) is an essential mechanism of the body to defend against exogenous carcinogen-induced DNA damage. Defects in NER may impair DNA repair capacity and, therefore, increase genome instability and cancer susceptibility. To explore genetic predispositions to Wilms tumor, we conducted a case-control study totaling 145 neuroblastoma cases and 531 healthy controls. We systematically selected 19 potentially functional SNPs in six key genes within the NER pathway (ERCC1, XPA, XPC, XPD, XPF, and XPG). The odds ratio (OR) and 95% confidence interval (CI) were calculated to measure the strength of associations. We identified significant associations between two XPD SNPs and Wilms tumor risk. The XPD rs3810366 polymorphism significantly enhanced Wilms tumor risk (dominant model: adjusted OR = 2.12, 95% CI = 1.26-3.57). Likewise, XPD rs238406 conferred a significantly increased risk for the disease (dominant model: adjusted OR = 2.30, 95% CI = 1.40-3.80; recessive model: adjusted OR = 1.64, 95% CI = 1.11-2.44). Moreover, online expression quantitative trait locus (eQTL) analysis demonstrated that these two polymorphisms significantly affected XPD gene expression in transformed fibroblast cells. Our study provides evidence of the association between the two XPD polymorphisms and Wilms tumor risk. However, these findings warrant validation in larger studies.

Base Excision Repair Gene Polymorphisms and Wilms Tumor Susceptibility

Base excision repair (BER) is the main mechanism to repair endogenous DNA lesions caused by reactive oxygen species. BER deficiency is linked with cancer susceptibility and premature aging. Single nucleotide polymorphisms (SNPs) within BER genes have been implicated in various human malignancies. Nevertheless, a comprehensive investigation of their association with Wilms tumor susceptibility is lacking. In this study, 145 cases and 531 sex and age-matched healthy controls were recruited. We systematically genotyped 18 potentially functional SNPs in six core BER pathway genes, using a candidate SNP approach. Logistic regression was employed to evaluate odds ratio (OR) and 95% confidence interval (CI) adjusted for age and gender. Several SNPs showed protective effects against Wilms tumor. Significant associations with Wilms tumor susceptibility were shown for hOGG1 rs1052133 (dominant: adjusted OR = 0.66, 95% CI = 0.45-0.96, P = .030), FEN1 rs174538 (dominant: adjusted OR = 0.66, 95% CI = 0.45-0.95, P = .027; recessive: adjusted OR = 0.54, 95% CI = 0.32-0.93 P = .027), and FEN1 rs4246215 (dominant: adjusted OR = 0.55, 95% CI = 0.38-0.80, P = .002) polymorphisms. Stratified analysis was performed by age, gender, and clinical stage. Moreover, there was evidence of functional implication of these significant SNPs suggested by online expression quantitative trait locus (eQTL) analysis. Our findings indicate that common SNPs in BER genes modify susceptibility to Wilms tumor.

Incidence and survival differences in esophageal cancer among ethnic groups in the United States

Objectives

This study was performed to identify the differences in incidence, clinicopathological features, and survival in esophageal cancer among ethnic groups in the United States and to determine the reasons for the differences.

Result

A total of 49,766 patients were included. Black and Asian groups had a higher proportion of squamous cell carcinoma (ESCC) (85.5% and 75.4%, respectively) and mid-esophagus tumor (43.2% and 37.7% respectively) than the non-Hispanic white and Hispanic white groups. The incidences of ESCC in all ethnic groups declined since 1973, especially in black males. At the same time, incidences of esophageal adenocarcinoma (EAC) dramatically increased in white males since 1973. And incidences of ESCC and EAC were the lowest and stable in Asian female. Multivariable models showed that patients who were male, or black, or had larger tumors, or positive lymph nodes had an increased risk of death from esophageal cancer, while patients with ESCC or diagnosed after 2005 or treated with surgery had a lower likelihood of death. For ESCC, the black patients had the lowest DSS, while for EAC there were no significant differences in DSS among the ethnic/racial groups.

Materials and Method

From the Surveillance, Epidemiology, and End Results Program database, patients diagnosed with esophageal cancer from 1998-2013 were identified. Differences in incidences, clinicopathological features, treatments, and disease-specific survival (DSS) in four broad racial/ethnic groups were compared.

Conclusion

Histological type distribution between racial groups could be an important consideration in the incidence and the survival trend but other factors could also have an effect.

Genetic Variants Within MTORC1 Genes Predict Gastric Cancer Prognosis in Chinese Populations

Objective: Mammalian target of rapamycin complex 1 (mTORC1) plays an important role in maintaining proper cellular functions in gastric cancer (GC). Previous studies demonstrated genetic variants within mTORC1 genes were associated with GC risk. However, no studies reported the associations between genetic variants within mTORC1 genes and GC prognosis. Herein, we firstly assessed the associations of genetic variants of mTORC1 genes with overall survival (OS) of GC in Chinese populations.

Methods: We genotyped eight single nucleotide polymorphisms (SNPs) in mTORC1 genes (i.e., rs2536 T>C and rs1883965 G>A for mTOR, rs3160 T>C and rs26865 A>G for MLST8, rs3751934 C>A, rs1062935 T>C, rs3751932 T>C and rs12602885 G>A for RPTOR) by the TaqMan method in 197 Chinese GC patients who had surgical resection in Xinhua Hospital. We conducted Kaplan-Meier survival plots and Cox hazards regression analysis to explore the associations of these SNPs with OS.

Results: The single-locus analysis indicated that RPTOR rs1062935 T>C was associated with an increased risk of poor GC prognosis (CC vs. TT/TC: adjusted Hazard ratio (HR) = 1.71, 95% confidence interval (CI) = 1.04-2.82). The combined analysis of all eight SNPs showed that patients with more than three risk genotypes significantly increased risk of death (adjusted HR = 2.44, 95% CI = 1.30-4.58), when compared to those with three or less risk genotypes.

Conclusions: Our findings indicated that genetic variants within mTORC1 genes may predict GC prognosis in Chinese populations. The results need to be validated in future studies with larger sample sizes.

Study of single nucleotide polymorphisms of FBW7 and its substrate genes revealed a predictive factor for paclitaxel plus cisplatin chemotherapy in Chinese patients with advanced esophageal squamous cell carcinoma

Paclitaxel plays a major role in the treatment of advanced esophageal squamous cell carcinoma. However, there is no biomarker that could be used to predict the clinical response of paclitaxel. This work was conducted to investigate the association of genetic polymorphisms in FBW7 and its substrate genes and the clinical response of paclitaxel. Patients with advanced esophageal squamous cell carcinoma were treated with paclitaxel 175 mg/m2 over 3 hours day 1 and cisplatin 75 mg/m2 day 1, every 3 weeks. The genotypes of 11 FBW7 and its substrate gene polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Statistical analysis revealed that patients with mTOR rs1057079 AG (ORadjusted: 4.59; 95% CI: 1.78-11.86) genotype had significant correlation with the clinical response of paclitaxel when compared with AA genotype after adjustment for sex, age, and chemotherapy cycle. The median progression-free survival (PFS) of patients with advanced ESCC who received paclitaxel plus cisplatin (TP) as first-line treatment is 14.3 months (95% CI: 9.0-19.60 months). The median PFS (mPFS) of AG genotypes and AA genotypes in mTOR rs1057079 were 17.31 months (95% CI: 15.9-18.67 months) and 9.8 months (95% CI: 8.58-11.02 months) (p=0.019), respectively.

The Expression and Prognostic Impact of the PI3K/AKT/mTOR Signaling Pathway in Advanced Esophageal Squamous Cell Carcinoma

The abnormal phosphatase and tensin homolog expression and activated phosphoinositide-3 kinase/Protein kinase B (AKT)/mammalian target of rapamycin signaling pathway are involved in the progression of esophageal squamous cell carcinoma. By assessing the expression pattern of key components in the phosphoinositide-3 kinase/AKT/mammalian target of rapamycin signaling pathway by immunohistochemistry in tumor and nontumor esophageal mucosa from patients with esophageal squamous cell carcinomas, we aimed to carefully explore the relationship between the various protein expressions and clinicopathological factors, as well as patient outcome. A total of 145 tumor and 145 nontumor samples from patients with esophageal squamous cell carcinoma, collected from HuaShan Hospital (Shanghai, China) were evaluated. Clinical characteristics, the targeted protein expressions (including phosphatase and tensin homolog, phosphoinositide-3 kinase, AKT, p-AKT, mammalian target of rapamycin, p-mTOR, p70S6 kinase 1, p-P70S6K1, elongation initiation factor 4E binding protein-1, and p-4E-BP1, and survival rate were analyzed. Among them, phosphoinositide-3 kinase, AKT, p-AKT, mammalian target of rapamycin, p-mTOR, elongation initiation factor 4E binding protein-1, p70S6 kinase 1, and p-P70S6K1 proteins were significantly upregulated in tumor tissue. Conversely, phosphatase and tensin homolog was largely downregulated in tumor tissue, notably in pT3-T4 tumors. Low expression of phosphatase and tensin homolog whereas high expression of mammalian target of rapamycin signaling components in tumors was closely related to the presence of lymph node metastases and advanced TNM stage (all P < .05). Moreover phosphatase and tensin homolog, mammalian target of rapamycin, and p70S6 kinase 1 were correlated with overall survival as well as p-mTOR was correlated with progression-free survival (all P < .05). Overexpression of mammalian target of rapamycin was proved to be an independent adverse prognostic factor for overall survival in esophageal squamous cell carcinomas. Our results suggest that the phosphoinositide-3 kinase/AKT/mammalian target of rapamycin signaling pathway is activated in esophageal squamous cell carcinoma, with the low expression of phosphatase and tensin homolog and the high expression of the mammalian target of rapamycin component proteins (both total and phosphorylated) in tumor tissue. Our result might offer a new strategy for specific targeted therapy and prognostic assessment in esophageal cancer.

Associations of genetic polymorphisms in pTEN/AKT/mTOR signaling pathway genes with cancer risk: A meta-analysis in Asian population

The pTEN/AKT/mTOR signaling pathways play a critical role in balancing cell proliferation, differentiation, and survival. Recent studies researched the associations of core genes in the pTEN/AKT/mTOR pathway polymorphisms with the cancer susceptibility; however, the results are inconclusive. Therefore, a systematically meta-analysis was performed to evaluate the association between the five SNPs (mTOR rs2295080 and rs2536, AKT1 rs2494750 and rs2494752, pTEN rs701848) and cancer risk by systematic review of the literature in 31 eligible studies. The results showed a significant decreased risk between rs2295080 TG, GG genotype, and GG/TG genotypes and overall cancer [TG vs.TT: OR(95% CI) = 0.82(0.76, 0.89), GG/TG vs. TT: OR(95% CI) = 0.82(0.76, 0.88), and GG vs. TG/TT: OR(95% CI) = 0.67(0.51, 0.88)] and the subgroup of urinary system cancer and digestive system cancer. Moreover, the SNP rs701848 CC, TC genotype showed significantly increased the overall cancer risk both in dominant model [CC/TC vs. TT: OR(95% CI) = 1.25(1.15, 1.36)] and recessive model [CC vs. TC/TT: OR(95% CI) = 1.20(1.09, 1.32)], and digestive system cancer and urinary system cancer. In addition, AG genotype and GG/AG genotype of rs2494752 was associated with increased risk of cancer. Therefore, this meta-analysis provided genetic risk factors for carcinogenesis and the most valid cancer prevalence estimate for Asian population.

Impact of phosphoinositide-3-kinase and vitamin D3 nuclear receptor single-nucleotide polymorphisms on the outcome of malignant melanoma patients

BACKGROUND

Several studies associating single nucleotide polymorphisms (SNPs) frequencies with tumors outcome have been conducted, nevertheless malignant melanoma literature data are inconclusive.Therefore we evaluate the impact of different genotypes for phosphoinositide-3-kinase (PI3K) and vitamin D3 nuclear receptor (VDR) SNPs on melanoma patients' outcome.

MATERIALS AND METHODS

Genomic DNA of 88 patients was extracted from blood and tumor samples. SNPs were determined by PCR using TaqMan assays. We selected polymorphisms of the regulatory and catalytic subunit of PI3K (PIK3R1 and PIK3CA genes, respectively), analyzing rs2699887C>T of PIK3CA and rs3730089G>A of PIK3R1 SNPs. Furthermore we considered the following VDR SNPs: rs2228570A>G (Fok1), rs731236A>G (Taq1) and rs1544410C>T (Bsm1).Progression free survival (PFS) and overall survival (OS) were estimated with the Kaplan-Meier method and with Mantel-Haenszel log-rank test.

RESULTS

The statistical analysis for Fok1 of VDR showed a significant difference in PFS after the first line therapy (median PFS= 21.2 months in the homozygous recessive genotype group vs. 3.3 months of homozygous dominant and heterozygous ones, p= 0.03). In particular, in homozygous recessive patients for Fok1 SNPs of VDR a high rate of histological regression and BRAF (B- Rapidly Accelerated Fibrosarcoma gene) mutation were observed. Furthermore, more efficacy of BRAF +/- MEK (MAPK-ERK-Kinase) inhibitors therapies in homozygous recessive patients vs. homozygous dominant and heterozygous ones was shown.

CONCLUSIONS

Our study showed a significant correlation between homozygous recessive genotype of Fok1 SNPs of VDR gene and an increased PFS in patients who underwent a first line therapy with BRAF inhibitors.

Ribosomal DNA copy number loss and sequence variation in cancer

Ribosomal DNA is one of the most variable regions in the human genome with respect to copy number. Despite the importance of rDNA for cellular function, we know virtually nothing about what governs its copy number, stability, and sequence in the mammalian genome due to challenges associated with mapping and analysis. We applied computational and droplet digital PCR approaches to measure rDNA copy number in normal and cancer states in human and mouse genomes. We find that copy number and sequence can change in cancer genomes. Counterintuitively, human cancer genomes show a loss of copies, accompanied by global copy number co-variation. The sequence can also be more variable in the cancer genome. Cancer genomes with lower copies have mutational evidence of mTOR hyperactivity. The PTEN phosphatase is a tumor suppressor that is critical for genome stability and a negative regulator of the mTOR kinase pathway. Surprisingly, but consistent with the human cancer genomes, hematopoietic cancer stem cells from a Pten^-/- mouse model for leukemia have lower rDNA copy number than normal tissue, despite increased proliferation, rRNA production, and protein synthesis. Loss of copies occurs early and is associated with hypersensitivity to DNA damage. Therefore, copy loss is a recurrent feature in cancers associated with mTOR activation. Ribosomal DNA copy number may be a simple and useful indicator of whether a cancer will be sensitive to DNA damaging treatments.

The ribosomal DNA encodes the RNAs needed to make ribosomes for protein synthesis and cellular proliferation. However, ribosomal DNA has been excluded from most mammalian genome-wide studies due to challenges associated with its analysis. We find that both the sequence and copy number of the ribosomal DNA can change in human cancer genomes. mTOR is a kinase that senses the nutritional environment and is often over-active in cancer. Given mutational evidence for mTOR activation in the human cancer genomes with loss of ribosomal DNA copies, we analyzed ribosomal DNA in hematopoietic stem cells derived from mice under conditions of mTOR activation. Like the human cancer genomes, the ribosomal DNA copy number contracts in mTOR activated hematopoietic stem cells relative to normal stem cells. Loss is associated with high rates of cellular proliferation, rRNA production, and protein synthesis, but compromised survival in the presence of DNA damage. Contractions are a recurrent feature in cancer genomes with overactive mTOR and may predict sensitivity to DNA damaging chemotherapeutics. Ribosomal DNA may be altered in other disease contexts.

APIO-EE-9 is a novel Aurora A and B antagonist that suppresses esophageal cancer growth in a PDX mouse model

Esophageal cancer (EC) is one of the most aggressive malignancies of the upper aerodigestive tract. Over the past three decades, with advances in surgical techniques and treatment, the prognosis of esophageal cancer has only slowly improved. Thus identifying novel molecular targets and developing therapeutic agents are critical. Aurora kinases play a crucial role in mitosis and selective inhibitors might provide an effective therapeutic treatment for cancer. However, the role of Aurora kinases in EC is still inadequately studied. Here, we identified a novel compound, referred to as APIO-EE-9, which inhibits growth and colony formation and induces apoptosis of esophageal cancer cells. Using computer modeling, we found that APIO-EE-9 interacted with both Aurora A and B in the ATP-binding pocket. APIO-EE-9 inhibited both Aurora A and B kinase activities in a dose-dependent manner. Treatment with APIO-EE-9 substantially reduced the downstream Aurora kinase phosphorylation of histone H3 (Ser10), resulting in formation of multiple nuclei and centrosomes. Additionally, esophageal cancer cells expressing shAurora A or shAurora B kinase exhibited a dramatic reduction in proliferation and colony formation. Injection of these cells as xenografts in mice reduced tumor formation compared to wildtype cells. Importantly, APIO-EE-9 significantly decreased the size of esophageal patient-derived xenograft (PDX) tumors implanted in SCID mice. These results demonstrated that APIO-EE-9 is a specific Aurora kinase inhibitor that could be developed as a therapeutic agent against esophageal cancer.

Gene polymorphisms in the PI3K/AKT/mTOR signaling pathway contribute to prostate cancer susceptibility in Chinese men

In this hospital-based case-control study of 413 prostate cancer (PCa) cases and 807 cancer-free controls, we investigated the role of functional single nucleotide polymorphisms (SNPs) of pivotal genes in the PI3K/AKT/mTOR pathway. We genotyped 17 SNPs in mTOR, Raptor, AKT1, AKT2, PTEN, and K-ras and found that 4 were associated with PCa susceptibility. Among the variants, the homozygote variant CC genotype of mTOR rs17036508 C>T were associated with higher PCa risk than the wild TT genotypes (adjusted OR = 3.73 (95% CI = 1.75-7.94), P = 0.001). The GT genotype of mTOR rs2295080 G>T was more protective than the TT genotypes (adjusted OR=0.54 (95% CI=0.32-0.91), P=0.020). The distributions of Raptor rs1468033 A>G genotypes differed between cases and controls, especially in subgroups defined by age, BMI, smoking status, and ethnicity. The CT/CC genotypes of AKT2 rs7250897 C>T were associated with an increased risk of PCa, particularly in subgroups of age >71 and BMI >24 kg/m². These findings suggest that SNPs in the PI3K/AKT/mTOR pathway may contribute to the risk of PCa in Chinese men.

Genetic polymorphisms (rs10636 and rs28366003) in metallothionein 2A increase breast cancer risk in Chinese Han population

Genetic polymorphisms of MT2A are frequently observed in many different cancers. We performed this case-control study, including 459 breast cancer (BC) patients and 549 healthy controls from Northwest China, to evaluate the associations between two common MT2A polymorphisms (rs10636 and rs28366003) and BC risk. The MT2A polymorphisms were genotyped via Sequenom MassARRAY. The individuals with the rs28366003 A/G, A/G-G/G genotypes underwent a higher risk of BC (P<0.0001). And, the minor allele G of rs28366003 was related to an increased BC risk (P<0.0001). We also found a significantly increased BC risk with rs10636 polymorphism among homozygote and recessive models (P<0.05). Further subgroup analysis by clinical characteristics of BC patients showed that Scarff, Bloom and Richardson tumor grade (SBR) 1-2 have a higher expression of the minor allele of these two MT2A loci than SBR 3. Our results indicated that the rs10636 and rs28366003 polymorphisms in MT2A increased BC risk in Northwest Chinese Han population.

BARD1 Gene Polymorphisms Confer Nephroblastoma Susceptibility

BRCA1-associated RING domain protein 1 (BARD1) is a tumor suppressor, which forms a heterodimer with BRCA1. Three BARD1 gene polymorphisms (rs7585356 G>A, rs6435862 T>G and rs3768716 A>G) were initially identified as high-risk neuroblastoma susceptibility loci by a previous GWAS. Because of the general tumor-suppressing function of BARD1, we hypothesized that these BARD1 gene polymorphisms might modify the susceptibility to nephroblastoma. We genotyped these polymorphisms in 145 cases and 531 controls using Taqman methods. Out of three polymorphisms, only the rs7585356 G>A polymorphism was significantly associated with increased susceptibility to nephroblastoma [AA vs. GG: adjusted odds ratio (OR)=1.78, 95% confidence interval (CI)=1.01-3.12]. Combined analysis of three polymorphisms indicated that subjects with 3 risk genotypes exhibited significantly elevated nephroblastoma risk, when compared with subjects with 0-2 risk genotypes (adjusted OR=1.72, 95% CI=1.02-2.89). Stratified analysis revealed that in term of clinical stage, rs7585356 AA carriers were associated with increased risk of developing clinical stage I+II nephroblastoma. The presence of three risk genotypes was significantly associated with nephroblastoma risk in females and clinical stage I+II nephroblastoma. Our results suggested that BARD1 rs7585356 G>A may be associated with nephroblastoma risk.

Association of XPC Gene Polymorphisms with Colorectal Cancer Risk in a Southern Chinese Population: A Case-Control Study and Meta-Analysis

Xeroderma pigmentosum group C (XPC) is a key component of the nucleotide excision repair (NER) pathway. Dysfunctional XPC protein may impair NER-mediated DNA repair capacity and further lead to genomic instability and carcinogenesis. Two common nonsynonymous polymorphisms in the XPC gene, Lys939Gln (rs2228001 A > C) and Ala499Val (rs2228000 C > T), have been investigated in various types of cancer. We genotyped these two polymorphisms in 1141 cases with histologically confirmed colorectal cancer (CRC) and 1173 healthy controls to explore their causative association with CRC susceptibility. Overall, no association was observed between these two variants and the risk of CRC. Our meta-analysis also confirmed a lack of overall association. Stratified analyses were performed by age, gender, smoking status, pack-year, drinking status, tumor sites, and Duke's stages. We found that XPC Lys939Gln polymorphism was significantly associated with an increased CRC risk in subjects at 57 years of age or younger (adjusted odds ratio (OR) = 1.37, 95% confidence interval (CI) = 1.004-1.86, p = 0.047) and non-drinkers (adjusted OR = 1.53, 95% CI = 1.10-2.12, p = 0.011). Our results indicated that XPC Lys939Gln may be a low-penetrance CRC susceptibility polymorphism. Our findings warrant further validation.

Impacts of the mTOR gene polymorphisms rs2536 and rs2295080 on breast cancer risk in the Chinese population

Mammalian target of rapamycin (mTOR) gene polymorphisms exert the major effects on the regulation of transcriptional activity and miRNA binding or splicing, which may be associated with cancer risk by affecting mTOR gene expression. However, inconsistent results have been previously reported. The present study evaluated the correlation between mTOR rs2536/rs2295080 polymorphisms and breast cancer risk. This case-control study was performed with 560 breast cancer patients and 583 healthy controls from the northwest of China. mTOR polymorphisms (rs2536 and rs2295080) were genotyped by Sequenom MassARRAY. We assessed the associations with odds ratios (ORs) and 95% confidence intervals (95% CIs). The association between mTOR rs2536 polymorphism and breast cancer risk was undetectable in our study (P > 0.05). In parallel, the significant effects were observed between mTOR rs2295080 polymorphism and breast cancer risk in the allele, codominant, and recessive models (P < 0.05). We detected no significant correlations between rs2536 polymorphism and the clinical parameters of breast cancer patients, while rs2295080 polymorphism was associated with lymph node (LN) metastasis. The Crs2536Grs2295080 haplotype was correlated with a significantly decreased risk of breast cancer (P < 0.05). In sum, the findings suggested that mTOR rs2295080 had a protective role on breast cancer susceptibility among Chinese population, while rs2536 polymorphism had no association with breast cancer risk.

Genetic polymorphisms of mTOR and cancer risk: a systematic review and updated meta-analysis

mTOR regulates several cellular processes that are critical for tumorigenesis. However, previous studies on the association of mTOR polymorphisms with predisposition to different cancer types are somewhat contradictory. Therefore, we performed a systematic review and updated meta-analysis of the available evidence regarding the relationship between mTOR single nucleotide polymorphisms (SNPs) and cancer risk. Up to November 2015, 23 original publications were identified covering 20 mTOR SNPs, of which seven SNPs (rs2536, rs2295080, rs1883965, rs1034528, rs17036508, rs3806317 and rs1064261) were included in the final meta-analysis. We estimated the summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for mTOR polymorphisms and cancer risk, and used the model-free approach to investigate the biological effect of each polymorphism. Our meta-analysis found that rs1883965, rs1034528, and rs17036508 were correlated with increased cancer risk in the complete over-dominant model (rs1883965 GA versus GG/AA: fixed-effects OR=1.15, 95% CI 1.02-1.29; rs1034528 GC versus GG/CC: fixed-effects OR=1.30, 95% CI 1.13-1.48; rs17036508 TC versus CC/TT: fixed-effects OR=1.23, 95% CI 1.06-1.43). Stratifying analyses by cancer type, we found that the rs2295080 G allele was associated with a significantly higher risk of acute leukemia in the recessive model (GG versus GT/TT: fixed-effects OR=2.08, 95% CI 1.34-3.22) and a lower risk of genitourinary cancers in the dominant model (TG/GG versus TT: fixed-effects OR=0.77, 95% CI 0.68-0.86). Interestingly, further expression analysis showed that homozygous variant genotype carriers of rs1883965, rs1034528 and rs17036508 had lower mTOR transcript levels, based on HapMap data.

Polymorphisms in the AKT1 and AKT2 genes and oesophageal squamous cell carcinoma risk in an Eastern Chinese population

Ethnic Han Chinese are at high risk of developing oesophageal squamous cell carcinoma (ESCC). Aberrant activation of the AKT signalling pathway is involved in many cancers, including ESCC. Some single nucleotide polymorphisms (SNPs) in genes involved in this pathway may contribute to ESCC susceptibility. We selected five potentially functional SNPs in AKT1 (rs2494750, rs2494752 and rs10138277) and AKT2 (rs7254617 and rs2304186) genes and investigated their associations with ESCC risk in 1117 ESCC cases and 1096 controls in an Eastern Chinese population. None of individual SNPs exhibited an association with ESCC risk. However, the combined analysis of three AKT1 SNPs suggested that individuals carrying one of AKT1 variant genotypes had a decreased ESCC risk [adjusted odds ratio (OR) = 0.60, 95% CI = 0.42-0.87]. Further stratified analysis found that AKT1 rs2294750 SNP was associated with significantly decreased ESCC risk among women (adjusted OR = 0.63, 95% CI = 0.43-0.94) and non-drinkers (OR = 0.79, 95% CI = 0.64-0.99). Similar protective effects on women (adjusted OR = 0.56, 95% CI = 0.37-0.83) and non-drinker (adjusted OR = 0.75, 95% CI = 0.60-0.94) were also observed for the combined genotypes of AKT1 SNPs. Consistently, logistic regression analysis indicated significant gene-gene interactions among three AKT1 SNPs (P < 0.015). A three-AKT1 SNP haplotype (C-A-C) showed a significant association with a decreased ESCC risk (adjusted OR = 0.70, 95% CI = 0.52-0.94). Multifactor dimensionality reduction analysis confirmed a high-order gene-environment interaction in ESCC risk. Overall, we found that three AKT1 SNPs might confer protection against ESCC risk; nevertheless, these effects may be dependent on other risk factors. Our results provided evidence of important gene-environment interplay in ESCC carcinogenesis.

Genetic variant rs4072037 of MUC1 and gastric cancer risk in an Eastern Chinese population

Published data on the association between the MUC1 rs4072037A > G polymorphism and gastric cancer (GCa) risk were inconclusive. To derive a more precise estimation of the association, we conducted a large GCa study of 1,124 cases and 1,192 controls to confirm this association in an Eastern Chinese population. Our results showed that the G allele was strongly associated with a decreased GCa risk in the study population [GG vs. AA, odds ratio (OR) = 0.47, 95% confidence interval (CI) = 0.31-0.73; AG/GG vs. AA, OR = 0.82, 95% CI = 0.68-0.99; GG vs. AA/AG, OR = 0.48, 95% CI = 0.32-0.74]. These associations remained significant in subgroups of age, tumor site, drinking and smoking status. Moreover, this association was supported by an additional meta-analysis of published studies. In summary, these results suggest that the MUC1 rs4072037G allele may be a low-penetrating protection factor for GCa risk in Chinese populations.

Overexpression of microRNA-634 suppresses survival and matrix synthesis of human osteoarthritis chondrocytes by targeting PIK3R1

Osteoarthritis (OA) is a degenerative disease characterized by deterioration of articular cartilage. Recent studies have demonstrated the importance of some microRNAs in cartilage damage. The aim of this study was to identify and characterize the expression of microRNA-634 (miR-634) in normal and OA chondrocytes, and to determine its role in OA pathogenesis. Human normal and OA chondrocytes obtained from patients were cultured in vitro. Transfection with miR-634 mimic or inhibitor was employed to investigate the effect of miR-634 on chondrocyte survival and matrix synthesis, and to identify miR-634 target. The results indicated that miR-634 was expressed at lower level in high grade OA chondrocyte compared with normal chondrocytes. Overexpression of miR-634 could inhibit cell survival and matrix synthesis in high grade OA chondrocytes. Furthermore, miR-634 targeted PIK3R1 gene that encodes the regulatory subunit 1 of class I PI3K (p85α) and exerted its inhibitory effect on the phosphorylation of Akt, mTOR, and S6 signal molecules in high grade OA chondrocytes. Therefore, the data suggested that miR-634 could suppress survival and matrix synthesis of high grade OA chondrocytes through targeting PIK3R1 gene to modulate the PI3K/Akt/S6 and PI3K/Akt/mTOR/S6 axes, with important implication for validating miR-634 as a potential target for OA therapy.

PSCA polymorphisms and gastric cancer susceptibility in an eastern Chinese population

The prostate stem cell antigen (PSCA) gene, which encodes a prostate-specific antigen (PSA), was identified as a gene involved in cell adhesion and proliferation. The associations between the PSCA rs2294008 and rs2976392 single nucleotide polymorphisms (SNPs) and gastric cancer (GCa) susceptibility were still controversial. To derive a more precise estimation of the associations, we conducted a case-control study of 1,124 cases and 1,192 controls in an eastern Chinese population. We found that the rs2294008T variant genotypes were associated with an increased GCa risk in this study population (CT vs CC, OR=1.59, 95% CI=1.33-1.89 and CT+TT vs CC, OR=1.38, 95% CI=1.17-1.62). For SNP rs2976392, the variant A genotypes were also associated with an increased GCa risk (AG vs GG, OR=1.61, 95% CI=1.35-1.91 and AG+AA vs GG, OR=1.47, 95% CI=1.25-1.74). The results were further validated by a meta-analysis. In conclusion, the results indicated that the PSCA rs2294008 T and rs2976392 A alleles were low-penetrate risk factors for GCa in this study population. However, large and well-designed studies are warranted to validate our findings.

Genetic variant of PRKAA1 and gastric cancer risk in an eastern Chinese population

Published data on the association between PRKAA1 rs13361707 T > C polymorphism and gastric cancer (GCa) susceptibility were inconclusive. To derive a more precise estimation of the association, we conducted a large-scale GCa study of 1,124 cases and 1,194 controls to confirm this association in an eastern Chinese population. Our results showed that the C allele of PRKAA1 rs13361707 increased the GC risk in the study population [CT vs. TT, odds ratio (OR) = 1.72, 95% confidence interval (CI) = 1.40-2.12; CC vs. TT, OR = 2.15, 95%CI = 1.70-2.71; CT/CC vs. TT, OR = 1.86, 95%CI = 1.53-2.26; CC vs.TT/CT, OR = 1.49, 95%CI = 1.24-1.79]. In addition, the association of C allele with an increased GCa risk was still significant in subgroups, when stratified by age, sex, tumor site, drinking and smoking status. Moreover, the findings in the present study were validated by our further meta-analysis. In summary, these results indicated that the C allele of PRKAA1 rs13361707 was a low-penetrate risk factor for GCa.

The mTOR pathway in obesity driven gastrointestinal cancers: Potential targets and clinical trials

The mechanistic target of rapamycin (mTOR) is a crucial point of convergence between growth factor signalling, metabolism, nutrient status and cellular proliferation. The mTOR pathway is heavily implicated in the progression of many cancers and is emerging as an important driver of gastrointestinal (GI) malignancies. Due to its central role in adapting metabolism to environmental conditions, mTOR signalling is also believed to be critical in the development of obesity. Recent research has delineated that excessive nutrient intake can promote signalling through the mTOR pathway and possibly evoke changes to cellular metabolism that could accelerate obesity related cancers. Acting through its two effector complexes mTORC1 and mTORC2, mTOR dictates the transcription of genes important in glycolysis, lipogenesis, protein translation and synthesis and has recently been defined as a central mediator of the Warburg effect in cancer cells. Activation of the mTOR pathway is involved in both the pathogenesis of GI malignancies and development of resistance to conventional chemotherapy and radiotherapy. The use of mTOR inhibitors is a promising therapeutic option in many GI malignancies, with greatest clinical efficacy seen in combination regimens. Recent research has also provided insight into crosstalk between mTOR and other pathways which could potentially expand the list of therapeutic targets in the mTOR pathway. Here we review the available strategies for targeting the mTOR pathway in GI cancers. We discuss current clinical trials of both established and novel mTOR inhibitors, with particular focus on combinations of these drugs with conventional chemotherapy, radiotherapy and targeted therapies.

Teeth loss, teeth brushing and esophageal carcinoma: a systematic review and meta-analysis

Esophageal carcinoma (EC) is a serious malignancy, and its epidemiologic etiology is not fully explained. We performed this review to investigate the association between teeth loss and teeth brushing and the risk of EC. A systematic search was conducted to identify all relevant studies. The Q test and I(2) statistic were used to examine between-study heterogeneity. Pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were considered by fixed or random effects models. Furthermore, we conducted subgroup analyses based on study design, the studies' geographic regions and case type of origin. Modified Egger linear regression test was used to estimate publication bias. Ten articles were included. Pooled analyses indicated that teeth loss was associated with an increased risk of EC for Asians (OR, 1.52; 95% CI: 1.30, 1.78), and high frequency of teeth brushing was associated with a lower incidence of EC (OR, 0.62; 95%CI: 0.43, 0.89). Subgroup analyses showed consistent results and no publication bias existed. Teeth loss and teeth brushing play potential roles in the progressing of EC. People should take care of their oral health in daily life. And large well-designed researches are needed to fully describe the association between teeth health and EC risk.

Germline copy number loss of UGT2B28 and gain of PLEC contribute to increased human esophageal squamous cell carcinoma risk in Southwest China

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide with poor prognosis. Thus, identification of predictive biomarkers for early diagnosis and intervention is needed to improve patients' survival. Research shows that heritable mutations, such as single nucleotide polymorphisms (SNPs), contribute to human cancer susceptibility significantly. However, the association of copy number variations (CNVs), another major source of genetic variation, with ESCC risk remains poorly clarified. In this study, we aimed to identify ESCC risk-related CNVs based on candidate-gene strategy in a case-control study. A meta-analysis was first performed to identify the most variable chromosome regions of ESCC tissues. Bioinformatic analysis and dual-luciferase reporter assays were carried out to evaluate the properties of all recorded CNVs located on these regions. Six candidate CNVs located within well-known oncogenes and detoxification-associated enzymes were enrolled in the final analysis. A newly developed multiplex gene copy number quantitation method AccuCopy(TM) was employed to simultaneously genotype all six candidate sites in 404 ESCC patients and 402 cancer-free controls from Southwest China, and in 42 ESCC tissues. qRT-PCR was performed to measure UGT2B28 mRNA in cancerous and corresponding normal tissues. Unconditional logistic regression was applied to test association between germline CNV genotypes and ESCC risk. Relationship between germline copy number variation and somatic copy number alterations was further analyzed. Finally we found that copy number loss of UDP-glucuronosyltransferase family 2, polypeptide B28 (UGT2B28) and gain of plectin (PLEC) conferred increased ESCC risk (Adjusted OR = 2.085, 95% CI = 1.493-2.912, P < 0.001 for UGT2B28. Adjusted OR = 3.725, 95% CI = 1.026-13.533, P = 0.046 for PLEC). mRNA level was lower in UGT2B28 loss genotyped esophageal tissues than in two-copy tissues, indicating that UGT2B28 loss genotypes modify ESCC susceptibility perhaps by decreasing UGT2B28 expression level and enzyme activity. In addition, an association was drawn between germline copy number variations and somatic alterations for PLEC, UGT2B17 and UGT2B28, but not for other candidate loci.