The aim of this study is to evaluate the frequency of HPV infection and genotypes among women with normal and abnormal cytological results and its correlation according to the severity of the lesions as well as to investigate the correlation between the TERT gene expression levels and the cytological sub-group and to evaluate the correlation between the HPV infection and TERT gene expression levels as diagnostic and prognostic marker in cervical precursor lesions and cervical cancer.
Early events associated with disease progression and cervical cancer include hTERT up-regulation at the transcriptional level mediated by high-risk HPV E6 oncoproteins via indefinite mechanisms with concomitant immortal phenotype of the cell in vitro and increased replicative potential of cells in precancerous cervical lesions and cervical cancer. Materials and methods: This study is a prospective observational case-control study conducted in Obstetrics and Gynaecology Clinic in Pristina and Molecular and Biology-Genetics Department in Skopje. Cervical samples from 214 women (median age 45.28 years; range 20-65) from the Outpatient Clinic in University Clinical Center in Kosovo were tested for HPV-DNA and quantitative TERT gene expression after performing conventional Pap smear.
Table of Contents
1. INTRODUCTION
2. BACKGROUND
2.1. Cervix uteri and the squamocolumnar junction
2.2. CERVICAL DISEASE AND NEOPLASIA
2.3. CERVICAL PRECURSOR LESIONS
2.3.2. SCREENING
2.3.3. HPV testing in primary screening
2.3.4. Management of cervical precursor lesions – treatment
2.3.5 Follow–up after treatment
2.4. Human papillomaviruses (HPVs)
2.4.2. HPV genome organisation
2.4.3. Early genes E1, E2, E4-E7
2.4.4. Late proteins L1/L2
2.4.5. HPV life cycle
2.4.6. Epidemiology of the HPV infection and its role in malignant transformation
2.4.7. Host immune response and HPV infection
2.5. Evasion mechanism of HPV
2.5.1. HPV vaccines
2.6. Telomere structure
2.6.1. Telomerase activity and malignant transformation
3. MOTIVATION FOR THE RESEARCH
4. RESEARCH HYPOTHESIS
5. AIMS OF THE STUDY
5.1. The specific aims of the research
6. MATERIALS AND METHODS
6.1. Ethics
6.1.1. Inclusion and exclusion criteria
6.1.2. Preconditions for the screening
6.1.3. Population
6.1.4. Control group characteristics
6.1.5. Data collection
6.2. MOLECULAR analyses
6.2.1. DNA and RNA isolation
6.2.2. HPV detection and genotyping
6.2.3. Quantitative Real-Time PCR for telomerase gene expression
6.3. Statistical analysis
7. RESULTS
8. DISCUSSION
9. CONCLUSIONS
10. REFERENCES
Research Objectives and Key Topics
This doctoral dissertation aims to evaluate the frequency of HPV infection and its genotypes among women with varying cytological results and to investigate the correlation between TERT gene expression levels and cervical disease severity, establishing these as potential diagnostic and prognostic markers.
- Prevalence and genotype distribution of HPV in cervical samples.
- Molecular analysis of hTERT gene expression in precursor lesions and cervical cancer.
- Correlation between HPV infection, cytological abnormalities, and telomerase activity.
- Clinical utility of TERT gene expression as a diagnostic and prognostic biomarker.
Excerpt from the Book
2.6. TELOMERE STRUCTURE
Telomeres are hexanucleotide repetitive structures of TTAGGG associated with several proteins called shelterin and are found on the end of each chromosome (193). This complex of protective proteins called shelterin complex, comprises Telomere Repeat Factor 1 and 2 (TRF1 and TRF2), Repressor and Activator protein 1(RAP1), Protection of telomere 1(POT1), Tripeptidyl peptidase1 (TPP1) and TRF1and 2 interacting Nuclear protein 2 (TIN2) (193). They have a fundamental role in safeguarding of the chromosomal integrity and function as molecular clock for the cells.
Telomeres were firstly acknowledged in 1930s by Muller and McClintock using cytogenetic techniques in Zea Mays and Drosophilamelanogaster, respectively. It was concluded that these structures preserve chromosome integrity and prevent end to end fusion (194-195).
Later, studies in Tetrahymena thermophila in 1978, revealed the telomere DNA sequence, which consisted in TTGGGG repeats, similar to human variant that is TTAGGG/AATCCC for human telomeres (196).
Telomeres serve as capping structure for the end of chromosomes protecting them from end-to end fusion, they compensate chromosome shortening due to the end-replication problem and are also involved in several biological functions like gene expression, chromosome replication and homologous recombination and importantly serves as a molecular clock, which confines the lifespan of normal cells and their senescence (197). Progressive shortening of telomeres in cells is age-related. In 1960s Hayflick observed that cells divide until they reach a limit and this limited capacity for division was called replicative senescence or mortality stage 1 (M1) which is dependent on critical telomere shortening (198). Under circumstances in which p53 and Rbp gene products are inactivated byE6/E7 oncoproteins, cells can escape from the cell-cycle checkpoint and subsequently continue to replicate thus entering the mortality stage 2 (M2) which is characterised with massive cell death and very short telomeres (199). Infrequent fraction of the cells can stabilise and maintain telomere length by telomerase activation (199) although; alternative lengthening of telomeres(ALT) is another maintenance mechanism for the telomeres (200).
Summary of Chapters
1. INTRODUCTION: Provides a global overview of cervical cancer as a preventable disease and its disproportionate impact on low-resource countries due to screening disparities.
2. BACKGROUND: Details the biology of the cervix, HPV pathogenesis, the role of co-factors, immune evasion mechanisms, and the molecular role of telomeres and telomerase in malignant transformation.
3. MOTIVATION FOR THE RESEARCH: Explains the necessity of this study for Kosovo, emphasizing the need for reliable biomarkers to improve screening and reduce unnecessary treatments.
4. RESEARCH HYPOTHESIS: Proposes that TERT gene expression levels can distinguish between high-risk HPV-infected patients and those whose abnormalities will likely regress.
5. AIMS OF THE STUDY: Outlines the primary objectives, including evaluating TERT expression in various cytological groups and determining its prognostic value.
6. MATERIALS AND METHODS: Describes the study design, participant criteria, HPV genotyping techniques, and quantitative Real-Time PCR protocols used for hTERT measurement.
7. RESULTS: Presents data on HPV prevalence, genotype distribution, and the significant correlation between TERT overexpression and the severity of cervical lesions.
8. DISCUSSION: Interprets the study findings, compares them with existing literature, and addresses the clinical implications of using hTERT as a diagnostic tool.
9. CONCLUSIONS: Summarizes the major insights, advocating for organized screening programs and the implementation of molecular biomarkers for better patient management.
Keywords
Human papillomavirus, TERT gene, cervical cancer, telomerase activity, polymerase chain reaction, cervical intraepithelial neoplasia, biomarker, HPV genotype, clinical diagnosis, molecular oncology, HPV persistence, cytological abnormalities, carcinogenesis, gene expression, prognostic marker.
Frequently Asked Questions
What is the fundamental focus of this research?
The research focuses on the association between human telomerase reverse transcriptase (TERT) gene expression, HPV infection, and the progression of cervical disease in women.
What are the central thematic areas covered?
The work covers cervical carcinogenesis, the molecular biology of Human Papillomavirus (HPV), host immune response, telomere maintenance, and the clinical application of molecular markers for screening.
What is the primary objective or research question?
The study aims to determine if TERT gene expression levels can act as a diagnostic and prognostic biomarker to identify women at risk for cervical cancer, particularly in the context of HPV infection.
Which scientific methods are applied?
The study employs a prospective observational case-control design, utilizing PCR for HPV genotyping and quantitative Real-Time PCR (qRT-PCR) to measure TERT gene expression levels.
What topics are discussed in the main body?
The main body examines the pathology of cervical lesions, the molecular mechanisms of HPV-induced oncogenesis, host defense evasion, and the role of TERT as a biomarker in stratified cytological groups.
Which keywords best characterize this study?
Key terms include Human papillomavirus (HPV), TERT gene, cervical cancer, telomerase activity, PCR, and oncogenic markers.
Why is this study particularly significant for Kosovo?
This is the first study of its kind in Kosovo regarding HPV genotype prevalence, and it highlights the urgent need for an organized national screening program to reduce the incidence of cervical cancer.
What conclusion does the author draw regarding TERT as a biomarker?
The author concludes that TERT gene expression is a highly specific and sensitive marker for identifying high-grade cytological lesions and can complement cytology to improve the accuracy of cervical cancer screening.
- Arbeit zitieren
- Vjosa Zejnullahu (Autor:in), 2018, HPV infection and TERT gene expression levels. Association of the telomerase gene expression with cervical cancer and its precursor lesions and Human papillomavirus infection, München, GRIN Verlag, https://www.grin.com/document/1193090
