Leptin receptor Q223R polymorphism in Egyptian female patients with breast cancer

Genetic alterations in LEP and ADIPOQ genes and risk for breast cancer: a meta-analysis

Introduction

Breast cancer has a strong genetic predisposition, and its genetic architecture is not fully understood thus far. In this study, we aimed to perform a meta-analysis to evaluate the association of genetic alterations in LEP and ADIPOQ genes, as well as their receptor-encoded genes with risk for breast cancer.

Methods

Only published studies conducted in humans and written in English were identified by searching PubMed, SCOPUS, CINAHIL and Embase from their inception to October 2022. Eligibility assessment and data collection were completed independently by two researchers. Statistical analyses were done using the STATA software.

Results

After literature search, 33 publications were eligible for inclusion. Overall, LEP gene rs7799039-G allele (odds ratio [OR]: 0.78, 95% confidence interval [CI]: 0.62 to 0.98) and ADIPOQ gene rs1501299-T allele (OR: 1.41, 95% CI: 1.06 to 1.88) were associated with the significant risk of breast cancer. In subgroup analyses, differences in menopausal status, obesity, race, study design, diagnosis of breast cancer, genotyping method and sample size might account for the divergent observations of individual studies. Circulating leptin levels were comparable across genotypes of LEP gene rs7799039, as well as that of LEPR gene rs1137101 (P>0.05). Begg's funnel plots seemed symmetrical, with the exception of LEPR gene rs1137100 and ADIPOQ gene rs1501299.

Discussion

Taken together, we found, in this meta-analysis, that LEP gene rs7799039 and ADIPOQ gene rs1501299 were two promising candidate loci in predisposition to breast cancer risk.

Single-Nucleotide Polymorphisms in LEP and LEPR Associated With Breast Cancer Risk: Results From a Multicenter Case-Control Study in Chinese Females

Background

Leptin (LEP) plays a physiological role through its specific receptor (LEPR) and is involved in the occurrence and development of breast cancer. Our current study aimed at determining the influence of single-nucleotide polymorphisms (SNPs) in the genes coding for LEP and LEPR on breast cancer risk.

Methods

In the present study, 963 breast cancer cases and 953 controls were enrolled. Five SNPs of LEP and two of LEPR were chosen to evaluate the correlation of selected SNPs with breast cancer susceptibility among women in northern and eastern China. Analyses were further stratified by body mass index (BMI), waist–hip rate (WHR), estrogen receptor, and progesterone receptor status. The expression patterns of risk variant-associated genes were detected by expression quantitative trait locus (eQTL) analysis with eQTLGen and The Cancer Genome Atlas database.

Results

There were significant differences between breast cancer cases and control groups in the menopausal status and family history of breast cancer. Two SNPs (rs1137101 and rs4655555) of the LEPR gene decreased overall breast cancer risk, and other five SNPs showed no significant association with breast cancer risk. rs1137101 (GA vs. GG; adjusted OR = 0.719, 95% CI = 0.578–0.894, p = 0.003) and rs4655555 (TT vs. AA; adjusted OR = 0.574, 95% CI = 0.377–0.873, p = 0.009) significantly decreased breast cancer risk after Bonferroni correction for multiple testing. In subgroup analyses, the GA and GA + AA genotypes of LEPR rs1137101 associated with decreased breast cancer risk in the subgroup of BMI ≤ 24 kg/m² or WHR ≥ 0.85 after Bonferroni correction. Furthermore, we found that the expressions of rs4655555-associated gene LEPR and leptin receptor overlapping transcript (LEPROT) were upregulated in breast cancer tumor tissues compared with adjacent normal tissues, and a higher expression of LEPR in tumor tissues was correlated with poor prognosis of breast cancer patients using The Cancer Genome Atlas Breast Invasive Carcinoma (TCGA-BRCA) data.

Conclusion

Our study demonstrated that the polymorphisms rs1137101 and rs4655555 located in the LEPR gene decreased breast cancer risk in Chinese females, which might be a research-worthy bio-diagnostic marker and applied for early prediction and risk assessment of breast cancer.

Leptin, Both Bad and Good Actor in Cancer

Leptin is an important regulator of basal metabolism and food intake, with a pivotal role in obesity. Leptin exerts many different actions on various tissues and systems, including cancer, and is considered as a linkage between metabolism and the immune system. During the last decades, obesity and leptin have been associated with the initiation, proliferation and progression of many types of cancer. Obesity is also linked with complications and mortality, irrespective of the therapy used, affecting clinical outcomes. However, some evidence has suggested its beneficial role, called the "obesity paradox", and the possible antitumoral role of leptin. Recent data regarding the immunotherapy of cancer have revealed that overweight leads to a more effective response and leptin may probably be involved in this beneficial process. Since leptin is a positive modulator of both the innate and the adaptive immune system, it may contribute to the increased immune response stimulated by immunotherapy in cancer patients and may be proposed as a good actor in cancer. Our purpose is to review this dual role of leptin in cancer, as well as trying to clarify the future perspectives of this adipokine, which further highlights its importance as a cornerstone of the immunometabolism in oncology.

LEP (-2548G>A LEP) and LEPR (223Gln>Arg, 109Lys>Arg) polymorphisms as breast cancer risk factors in the Polish female population

On a global scale, breast cancer is the most common type of cancer in women, and it is still a growing problem. Therefore, new prognostic or diagnostic markers are required that would facilitate the assessment of patients or provide more efficient therapy, respectively. In these studies, we analyzed the contribution of LEP (2548G>A) and LEPR (109 Lys>Arg and 223Gln>Arg) genes polymorphisms to the risk of breast cancer development. The study involved 209 women aged 59.6 ± 11 years diagnosed with breast cancer and 202 healthy women aged 57.8 ± 8.2 years, who were blood donors. Polymorphism were evaluated by PCR–RFLP reaction followed by the verification of part of the samples by sequencing. The results of the study confirmed obesity as a significant breast cancer development risk factor in Polish women. However, no significant association between the studied polymorphisms and breast cancer risk or severity of the neoplastic disease was found. Interestingly, it was shown that wild type 223Gln>Gln leptin receptor (LEPR) was statistically more common in women with human epidermal growth factor receptor 2 negative (HER2−) than human epidermal groth factor receptor 2 positive (HER2+) breast cancer and wild type form of 2548G>A LEP was more common in women with progesterone receptor positive (PR+) than progesterone receptor negative (PR−) breast cancer. Studied polymorphisms of the LEP and LEPR genes do not increase breast cancer risk in the population of Polish women. However, they can affect PR an HER receptors expression and thus the severity of the disease. Noteworthy, this interesting correlation is being reported for the first time and might constitute an essential contribution to the identification of molecular mechanisms of carcinogenesis.

A Review of Cancer Genetics and Genomics Studies in Africa

Cancer is the second leading cause of death globally and is projected to overtake infectious disease as the leading cause of mortality in Africa within the next two decades. Cancer is a group of genomic diseases that presents with intra- and inter-population unique phenotypes, with Black populations having the burden of morbidity and mortality for most types. At large, the prevention and treatment of cancers have been propelled by the understanding of the genetic make-up of the disease of mostly non-African populations. By the same token, there is a wide knowledge gap in understanding the underlying genetic causes of, and genomic alterations associated with, cancer among black Africans. Accordingly, we performed a review of the literature to survey existing studies on cancer genetics/genomics and curated findings pertaining to publications across multiple cancer types conducted on African populations. We used PubMed MeSH terms to retrieve the relevant publications from 1990 to December 2019. The metadata of these publications were extracted using R text mining packages: RISmed and Pubmed.mineR. The data showed that only 0.329% of cancer publications globally were on Africa, and only 0.016% were on cancer genetics/genomics from Africa. Although the most prevalent cancers in Africa are cancers of the breast, cervix, uterus, and prostate, publications representing breast, colorectal, liver, and blood cancers were the most frequent in our review. The most frequently reported cancer genes were BRCA1, BRCA2, and TP53. Next, the genes reported in the reviewed publications’ abstracts were extracted and annotated into three gene ontology classes. Genes in the cellular component class were mostly associated with cell part and organelle part, while those in biological process and molecular function classes were mainly associated with cell process, biological regulation, and binding, and catalytic activity, respectively. Overall, this review highlights the paucity of research on cancer genomics on African populations, identified gaps, and discussed the need for concerted efforts to encourage more research on cancer genomics in Africa.

The Inter-Relation between Leptin Receptor (Q223R) Gene Polymorphism and the Risk of Egyptian Patients with HCC

Background:

The relationship of leptin (LEP) and polymorphism of leptin receptor (LEPR) were studied in patients with hepatocellular carcinoma (HCC) and compared with those with liver cirrhosis to find out the extent of the risk of LEPR on patients with HCC.

Methods:

Serum LEP level and LEPR Q223R gene polymorphism were determined in 300 patients with liver disease categorized equally into five groups’ healthy volunteers, patients with hepatitis C (HCV), patients with non-alcoholic steatohepatitis (NASH), liver cirrhosis and HCC. LEPR gene was amplified by polymerase chain reaction (PCR) then digested by the MSP1 restriction enzyme.

Results:

The isolated 212 bp of LEPR was sequenced. The serum LEP level was reduced in patients with cirrhotic and HCC. Serum LEP level had negatively correlated with both tumor grade and size in HCC patients. The data obtained from restriction fragment length polymorphismPCR and sequencing revealed the existence of a novel synonymous Q223R single nucleotide polymorphism (SNP) in exon 223 of LEPR gene (1137101). LEPR Gln223Arg, GG and GA genotypes were found in all studied groups. LEPR Gln223Arg, AA genotype was found in NASH, HCC, and control. LEPR Gln223Arg GA genotype is associated with some patients with HCC.

Conclusion:

GA genotype of LEPR Gln223Arg may be regarded as a probable genetic risk factor for Egyptian patients with HCC.

Leptin Levels and Q223R Leptin Receptor Gene Polymorphism in Obese Mexican Young Adults

INTRODUCTION

The Q223R polymorphism of the leptin receptor (LEPR) gene is one of the most common polymorphisms and it is believed to be associated with a damaged capacity of LEPR signaling and with high circulating leptin levels.

METHODS

An observational, cross-sectional, analytical study was carried out in the Autonomous University of Ciudad Juarez, Mexico, where a sample of young adult participants (ranging from 18 to 30 years of age) was obtained. They were classified based on the results of body mass index: non-obese, and overweight/obese. The polymorphic variant was determined by Polymerase Chain Reaction (PCR) from the DNA sample and serum leptin levels were measured by Enzyme-Linked Immuno Sorbent Assay.

RESULTS

A total of 159 participants were included (non-obese, n=103; overweight/obese, n=56). Leptin levels were 15.14±12.3 ng/mL in the non-obese group and 26.13±19.0 ng/mL in the overweight/obese group (p≤0.001). The allelic frequencies of the Q and R alleles of the LEPR gene in the studied subjects were as follows: non-obese, Q=0.56, R=0.44; overweight/obese, Q=0.62, R=0.38. The relative risk for the Q/Q genotype was 1.18 (Cl 0.53-2.34), for Q/R was 1.14 (Cl 0.59-2.18) and for R/R was 0.59 (Cl 0.23-1.50).

CONCLUSIONS

This study shows that leptin levels are associated with overweight/obesity in Mexican young adults, but this is not related to the presence of the Q223R polymorphism in the LEPR gene, so the underlying mechanisms for a possible disturbance in leptin signaling in obese Mexican young adults await further studies.

Investigation of leptin receptor rs1137101 G>A polymorphism with cancer risk: evidence from 35936 subjects

Leptin receptor (LEPR) signaling may be involved in promoting angiogenesis and proliferation, inhibiting apoptosis and playing a vital role in the progression of carcinogenesis. A number of studies have focused on the association of LEPR rs1137101 variants with susceptibility of cancer, however, the observed results were controversial. We searched literature on the relationship of LEPR rs1137101 G>A polymorphism with cancer risk by using PubMed and Embase databases, covering all publications up to 14 October 2018. In total, 44 case–control studies with 35,936 subjects were included. After combining all eligible studies, we identified null relationship between LEPR gene rs1137101 G>A polymorphism and overall cancer risk [A vs. G: odds ratio (OR ) =  0.97, 95% confidence interval (CI ) =  0.89–1.06, P = 0.547; AA vs. GG: OR  =  0.93, 95% CI  =  0.78–1.13, P = 0.476; AA/GA vs. GG: OR  =  0.99, 95% CI  =  0.91–1.09, P= 0.890 and AA vs. GA/GG: OR  = 0.92, 95% CI  =  0.82–1.04, P= 0.198]. However, in a subgroup analysis, there was an increased susceptibility of oral and oropharyngeal cancer in AA vs. GA/GG genetic model (OR, 1.83; 95% CI, 1.01–3.33; P=0.048). Considering the limited participants were included, the findings might be underpowered. Sensitivity analysis identified that any independent study omitted did not materially influence the pooled ORs and CIs. The results of publication bias detection showed that there was no evidence of bias. In summary, this analysis indicates that no significant association of cancer risk was identified to be correlated with rs1137101 G>A variants, even in stratified analyses.

Leptin-induced signaling pathways in cancer cell migration and invasion

BACKGROUND

Increasing evidence indicates that obesity is associated with tumor development and progression. Leptin is an adipocyte-related hormone with a key role in energy metabolism and whose circulating levels are elevated in obesity. The effect of leptin on cancer progression and metastasis and its underlying mechanisms are still unclear. Leptin can impact various steps in tumor metastasis, including epithelial-mesenchymal transition, cell adhesion to the extracellular matrix (ECM), and proteolysis of ECM components. To do so, leptin binds to its receptor (OB-Rb) to activate signaling pathways and downstream effectors that participate in tumor cell invasion as well as distant metastasis.

CONCLUSIONS

In this review, we describe metastasis steps in detail and characterize metastasis-related molecules activated by leptin, which may help to develop a roadmap that guides future work. In addition, we conclude that a profound understanding of the fundamental molecular processes that contribute to leptin-induced metastasis may pave the way for the development of new prognostic molecules and appropriate approaches to the treatment of obesity-related cancers.

Signaling Pathways Induced by Leptin during Epithelial⁻Mesenchymal Transition in Breast Cancer

Leptin is an adipokine that is overexpressed in obese and overweight people. Interestingly, women with breast cancer present high levels of leptin and of its receptor ObR. Leptin plays an important role in breast cancer progression due to the biological processes it participates in, such as epithelial⁻mesenchymal transition (EMT). EMT consists of a series of orchestrated events in which cell⁻cell and cell⁻extracellular matrix interactions are altered and lead to the release of epithelial cells from the surrounding tissue. The cytoskeleton is also re-arranged, allowing the three-dimensional movement of epithelial cells into the extracellular matrix. This transition provides cells with the ability to migrate and invade adjacent or distal tissues, which is a classic feature of invasive or metastatic carcinoma cells. In recent years, the number of cases of breast cancer has increased, making this disease a public health problem worldwide and the leading cause of death due to cancer in women. In this review, we focus on recent advances that establish: (1) leptin as a risk factor for the development of breast cancer, and (2) leptin as an inducer of EMT, an event that promotes tumor progression.

Association between serum leptin levels and breast cancer risk: An updated systematic review and meta-analysis

BACKGROUND

Many studies have indicated that leptin is correlated with breast cancer occurrence and tumor behavior. However, this issue remains controversial. Therefore, we conducted an updated meta-analysis to investigate the role of leptin in breast cancer.

METHODS

We performed a systematic literature search and identified relevant papers up to 1 September 2017. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to evaluate effect sizes.

RESULTS

Thirty-five eligible studies were included in the current meta-analysis. Serum leptin levels were related to breast cancer risk as demonstrated by calculations of the overall SMD = 0.46 (95% CI = 0.31-0.60, I = 93.5%). A subgroup analysis of BMI identified an association between breast cancer and serum leptin levels in patients who are overweight and obese (overweight: SMD = 0.35, 95% CI = 0.13-0.57, I = 88.1%; obesity: SMD = 1.38, 95% CI = 0.64-2.12, I = 89.6%). Additionally, menopausal status subgroup analysis revealed a significant association in postmenopausal women (SMD = 0.26, 95% CI = 0.12-0.40, I = 77.9%). Furthermore, we identified a significant association between breast cancer and serum leptin levels in Chinese women (SMD = 0.61, 95% CI = 0.44-0.79, I = 40.6%).

CONCLUSION

The results of this meta-analysis suggested that leptin could be a potential biomarker for breast cancer risk in women, especially overweight/obese or postmenopausal women. Therefore, it may be useful for identifying subjects with a high risk for breast cancer who may benefit from preventive treatments.

Obesity phenotype in relation to gene polymorphism among samples of Egyptian children and their mothers

Obesity is complex heterogeneous disease controlled by genes, environmental factors, and their interaction. Genetic factors account for 40-90% of the body mass index variations. Body mass index (BMI) of children correlates more closely with maternal than paternal BMI. So, this studu was aimed to investigate the role of leptin receptor LEPR Gln223Arg, the uncoupling protein 2 (UCP2 G 866 A) and insulin receptor gene (INSR exon 17) polymorphisms in the pathogenesis of obesity. A cross-sectional study executed on 130 children and their obese mothers; classified into 2 groups according to their BMI. The 2 groups were evaluated regarding the anthropometry. Restriction fragment length analysis for LEPR Gln223Arg, UCP2 -866 G/A and INSR exon 17 polymorphisms were applied. It was reported that increased risk of obesity was found in LEPR AG + AA genotype and the A allele. Significant statistical difference was detected only in female children. Concerning UCP2, the AG followed by the GG genotype was the most frequent in all groups and the G allele was the mostly present in obese mothers and obese male children but with no statistical significance. There was difference in the INSR genotype and alleles between groups, but this difference was not statistically significant. This study concluded that the LEPR Gln223Arg, UCP2 G 866 A and INSR exon 17 polymorphisms are related to obesity in Egyptian population. Further researches on larger population are recommended to ascertain the implications of LEPR, UCP2 and INSR polymorphisms in obesity.

Investigation of TCF7L2, LEP and LEPR polymorphisms with esophageal squamous cell carcinomas

Single nucleotide polymorphisms (SNPs) in energy metabolism related gene may be key agents in the development of human malignancies. In this study, we aimed to examine the association of transcription factor 7-like 2, Leptin (LEP) and LEP receptor (LEPR) polymorphisms with esophageal squamous cell carcinoma (ESCC). A total of 507 ESCC cases and 1,496 controls were enrolled. We found that LEPR rs6588147 AA genotype was associated with ESCC risk (AA vs. GG/GA: adjusted OR=1.90, 95%CI=1.00-3.61, P=0.049). In the stratified analyses, LEPR rs6588147 G>A polymorphism increased the risk of ESCC (<63 years subgroup: AA vs. GG: adjusted OR=2.58, 95%CI=1.00-6.62, P=0.049 and AA vs. GA/GG: adjusted OR=2.71, 95%CI=1.06-6.91, P=0.038; male subgroup: AA vs. GG: adjusted OR=2.19, 95%CI=1.02-4.67, P=0.044 and AA vs. GA/GG: adjusted OR=2.26, 95%CI=1.06-4.80, P=0.035). However, LEP rs7799039 A>G decreased the risk of ESCC (≥63 years subgroup: GG vs. AA: adjusted OR=0.47, 95%CI=0.23-0.95, P=0.035 and GG vs. AA/AG: adjusted OR=0.48, 95%CI=0.24-0.96, P=0.038; BMI≥24 kg/m² subgroup: AG vs. AA: adjusted OR=0.66, 95%CI=0.45-0.99, P=0.044). In addition, LEPR rs1137101 G>A polymorphism decreased ESCC risk in some subgroups (ever smoking subgroup: GA vs. GG: adjusted OR=0.66, 95%CI=0.44-1.00, P=0.049; ever drinking subgroup: GA vs. GG: adjusted OR=0.54, 95%CI=0.31-0.95, P=0.031 and GA/AA vs. GG: adjusted OR=0.54, 95%CI=0.31-0.93, P=0.027). Our findings suggest that LEPR rs6588147 G>A polymorphism is associated with the increased risk of ESCC; however, LEP rs7799039 A>G and LEPR rs1137101 G>A polymorphisms may be protective factors for ESCC.