Association of -463G/A MPO gene polymorphism and risk of cervical intraepithelial neoplasia

A comprehensive meta-analysis of non-coding polymorphisms associated with precancerous lesions and cervical cancer

OBJECTIVES

To study the risk of polymorphisms present in the non-coding regions of genes related with cervical cancer.

METHODS

The PubMed database was extensively searched using text-mining techniques to identify literature containing the association of single nucleotide polymorphisms and cervical cancer. Case-control studies published till June 2020 were considered for the meta-analysis if they fulfilled the selection criteria. The polymorphisms within each case-control study were checked for the presence of genotype data and then divided into groups based on the precancerous and cancerous conditions of the cervix. Odds ratio and 95% confidence intervals (CI) were used to study the effects of polymorphisms with the help of different genetic models (allele, dominant, recessive, heterozygous and homozygous). Also checked heterogeneity along with publication bias and statistical significance using the p-value.

RESULTS

120 papers covering 48 unique non-coding SNPs having 37,123 cases and 39,641 control data was considered for the meta-analysis. The genotype data was categorised into Cancer, Precancer and "Cancer + Precancer" groups, for 43, 8 and 11 SNPs respectively. The meta-analysis identified 21 and 1 SNPs as significant in the Cancer and "Cancer + Precancer" groups. Among all the polymorphisms, rs1143627 (IL1B), rs1800795 (IL6), rs1800871 (IL10), rs568408 (IL12A), rs3312227 (IL12B), rs2275913 (IL17A), rs5742909 (CTLA4), rs1800629 (TNFα), and rs4646903 (CYP1A1) were found to increase risk of cervical cancer in at least three of the five genetic models.

CONCLUSION

We identified potential non-coding SNPs corresponding to various cytokines like interleukins (ILs), tumor necrosis factor (TNF), interferon (IFN) and other immune related genes like toll like receptor (TLR), cytotoxic T-lymphocyte associated protein (CTLA) and matrix metalloproteinase (MMP), as significant with increased pooled OR in this meta-analysis pointing to risk association of the immune-related genes in cervical carcinogenesis.

Spotlight on TAP and its vital role in antigen presentation and cross-presentation

In the late 1980s and early 1990s, the hunt for a transporter molecule ostensibly responsible for the translocation of peptides across the endoplasmic reticulum (ER) membrane yielded the successful discovery of transporter associated with antigen processing (TAP) protein. TAP is a heterodimer complex comprised of TAP1 and TAP2, which utilizes ATP to transport cytosolic peptides into the ER across its membrane. In the ER, together with other components it forms the peptide loading complex (PLC), which directs loading of high affinity peptides onto nascent major histocompatibility complex class I (MHC-I) molecules that are then transported to the cell surface for presentation to CD8+ T cells. TAP also plays a crucial role in transporting peptides into phagosomes and endosomes during cross-presentation in dendritic cells (DCs). Because of the critical role that TAP plays in both classical MHC-I presentation and cross-presentation, its expression and function are often compromised by numerous types of cancers and viruses to evade recognition by cytotoxic CD8 T cells. Here we review the discovery and function of TAP with a major focus on its role in cross-presentation in DCs. We discuss a recently described emergency route of noncanonical cross-presentation that is mobilized in DCs upon TAP blockade to restore CD8 T cell cross-priming. We also discuss the various strategies employed by cancer cells and viruses to target TAP expression or function to evade immunosurveillance - along with some strategies by which the repertoire of peptides presented by cells which downregulate TAP can be targeted as a therapeutic strategy to mobilize a TAP-independent CD8 T cell response. Lastly, we discuss TAP polymorphisms and the role of TAP in inherited disorders.

Proteomic analysis of human cervical adenocarcinoma mucus to identify potential protein biomarkers

Background

Cervical cancer is the most common gynecological cancer, encompassing cervical squamous cell carcinoma, adenocarcinoma, and other epithelial tumors. There are many diagnostic methods to detect cervical cancers but no precision screening tool for cervical adenocarcinoma at present.

Material and methods

The cervical mucus from three normal cervices (Ctrl), three endocervical adenocarcinoma (EA), and three cervical adenocarcinoma in situ (AIS) was collected for proteomic analysis. The proteins were screened using liquid chromatography-mass spectrometry analysis (LC-MS). The biological function of the differently expressed proteins were predicted by Gene Ontology (GO).

Results

A total of 711 proteins were identified, including 237 differently expressed proteins identified in EA/Ctrl comparison, 256 differently expressed proteins identified in AIS/Ctrl comparison, and 242 differently expressed proteins identified in AIS/EA comparison (up-regulate ≥ 1.5 or down-regulate ≤ 0.67). Functional annotation was performed using GO analysis on 1,056 differently expressed proteins to identify those that may impact cervical cancer, such as heme protein myeloperoxidase, which is involved in the immune process, and APOA1, which is associated with lipid metabolism.

Conclusion

We used proteomic analysis to screen out differently expressed proteins from normal cervical mucus and cervical adenocarcinoma mucus samples. These differently expressed proteins may be potential biomarkers for the diagnosis and treatment of cervical adenocarcinoma but require additional study.

The possible association between the presence of an MPO -463 G > A (rs2333227) polymorphism and cervical cancer risk

PURPOSE

The association between myeloperoxidase (MPO) polymorphism and the risk of cervical cancer is inconclusive. We performed a meta-analysis to clarify if a correlation exists between MPO polymorphism and the risk for developing cervical cancer.

METHODS

All case-control research studies that determined a relationship between MPO and cervical cancer reported up until March 1, 2018 in PubMed, Web of Science, VIP, WanFang, and the CNKI Database were accessed and included. The strength of association was evaluated with pooled odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs). We used sensitivity analysis to detect the stability of our results, conducted Q-test to evaluate heterogeneity and applied Begg's funnel plot and Egger's test to investigate any publication bias among selected studies.

RESULTS

In this meta-analysis, we included 5 eligible studies in the final evaluation, which included 1125 patients with cervical cancer and 1150 cancer-free control patients. A potential association between the MPO -463 G > A polymorphism and cervical cancer risk was observed (recessive model: OR = 0.65, 95%, CI: 0.43-0.98, P = 0.038; homozygous model: OR = 0.65, 95%, CI: 0.43-0.99, P = 0.045), which indicates that genotype AA reduces the risk of cervical cancer by 35% compared to GG/GA or GG genotypes in our results. A stratified analysis by ethnicity identified a significant correlation among Caucasian patients (recessive model: OR = 0.57, 95%, CI: 0.34-0.95, P = 0.029; homozygous model: OR = 0.60, 95%, CI: 0.36-0.99, P = 0.048) and a stratified analysis by source of control identified a significant correlation among population-based studies.

CONCLUSIONS

Our results suggest that the presence of polymorphism, -463 G > A in patients might offer them protection against cervical cancer. By implementing randomized case-control or cohort studies with larger sample sizes, the clinical significance of our results can be further strengthened and verified.

Involvement of myeloperoxidase gene polymorphism 463G>A in development of cervical squamous cell carcinoma

BACKGROUND

The myeloperoxidase (MPO) -463G>A (rs2333227) polymorphism has been linked with increased susceptibility to the development of various malignancies. However, the data on the association of the MPO -463G>A transition with cervical cancer remain inconsistent.

METHODS

Using high resolution melting analysis we genotyped this polymorphism in women with cervical squamous cell carcinoma (SCC) (n = 476) and controls (n = 493) from a Polish Caucasian population. Logistic regression analysis was used to adjust for the effect of confounders such as age, parity, oral contraceptive use, tobacco smoking, and menopausal status, and revealed that the MPO -463G>A single nucleotide polymorphism (SNP) was associated with an increased risk of SCC.

RESULTS

The adjusted odds ratio (OR) for patients with the A/A genotype versus G/G genotype was 0.718 (95% CI 0.531-0.972, p = 0.0316). Stratified analyses between the MPO -463G>A polymorphism and SCC risks demonstrated a protective role of the MPO -463G>A SNP in patients with a positive history of parity and negative history of tobacco smoking. In patients with a positive history of parity, the age-adjusted OR for the A/A versus G/G genotype was 0.667 (95% CI 0.479-0.929, p = 0.0164). The age-adjusted OR for patients with a negative history of tobacco smoking for the A/A versus G/G genotype was 0.491 (95% CI 0.313-0.770, p = 0.0019).

CONCLUSIONS

Our study demonstrated that the MPO -463G>A SNP may protect from SCC in women from Polish Caucasian populations.