Abstract
OBJECTIVES:
Genetic susceptibility to cervical cancer in relation to transforming growth factor beta 1 (
STUDY DESIGN:
134 cervical cancer patients and 102 age-sex matched healthy controls were included from two institutions in Bangladesh. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used for genotyping two
RESULTS:
No significant correlation was found between polymorphisms C509T (rs1800469) and T869C (rs1800470) of
CONCLUSION:
In summary, two polymorphisms C509T and T869C of
Introduction
Cervical cancer accounts for 3.2% of the total newly diagnosed cancer cases and 3.26% of cancer related deaths worldwide [1]. In Bangladesh, it is the second leading cause of cancer related death among women [2]. Although human papillomavirus (HPV) is considered as an etiologic agent for cervical cancer, many other risk factors exist, as only few women who are exposed to this virus develop cancer [3]. HPV-16 and HPV-18 are considered as prime subtypes, causing 70% of cervical cancer worldwide [4]. In terms of other causes, molecular alterations of tumor suppressor genes and genetic polymorphisms play a vital role in the development of cervical cancer [5].
Transforming growth factor-beta (TGFB) superfamily is a collection of multifunctional cytokines including activins, inhibins, and bone morphogenetic proteins which are involved in different crucial physiological functions like-proliferation and differentiation of cell, angiogenesis, immunosuppression, cell motility, apoptosis, wound healing, and embryonic development [6]. Moreover, it has also been hypothesized to be involved in the cancer pathogenesis where it works as a tumor suppressor or a tumor promoter depending on the stage of tumor [7]. During early stages of carcinogenesis it functions as a tumor suppressor gene due to its ability to arrest cell cycle and induce apoptosis [7, 8].
Among three homologous isoforms of TGFB present in human and other mammals,
One study reported higher frequency of A allele of the polymorphism G800A (rs1800468) of
The C509T (rs1800469) and T869C (rs1800470) are the two most common polymorphisms of
Materials and methods
Subject selection and sample collection
A total of 236 women were recruited for conducting this study where 134 were cervical cancer patients and 102 were healthy controls. Cervical patients were recruited from the Bangabandhu Sheikh Mujib Medical University (BSMMU) and National Institute of Cancer Research and Hospital (NICRH), Dhaka, Bangladesh in between October 2018 and June 2019. All patients were histologically diagnosed with cervical cancer and categorized according to the International Federation of Gynecology and Obstetrics (FIGO) staging system [21]. All the cervical cancer patients were non-smokers and abstinent from consuming alcohol throughout their life. After performing physical assessment, age matched healthy controls were recruited. Healthy controls with head injury, trauma, history of psychiatric illness, pregnancy, alcohol intake, smoking, substance abuse were not recruited for the study.
All participants were informed about the study aim and experimental technique and written consent forms were taken prior to the study. This study was conducted according to the Declaration of Helsinki and its further amendments [22]. Laboratory experiments were carried out in the Pharmacogenetics and Pharmacokinetics lab at the Department of Clinical Pharmacy and Pharmacology, Faculty of Pharmacy, University of Dhaka. Finally, approval for the study protocol was taken from the ethical review committee of the Bangabandhu Sheikh Mujib Medical University (BSMMU) and National Institute of Cancer Research and Hospital (NICRH), Dhaka.
DNA extraction and genotyping
3 ml of blood samples were collected from all the participants in potassium-EDTA sterile tubes (Becton, Dickinson and Company, NJ, USA) and stored at –80°C prior to DNA extraction. Genomic DNA was extracted following previously published method [23]. The selected polymorphisms of
Statistical analysis
Chi-square (
Results
Characteristics of the study population
A total of 236 samples were taken in this study where 134 were cervical cancer patients and 102 were healthy controls. Table 1 contains the detailed demographic and clinicopathological features of the patients and the controls.
Distribution of clinicopathological features of cervical cancer patients and controls
#Combination: Oral pills+combined injectable contraceptives (CIC); Oral pills+condom (male) *Others: Barrier (cervical cup, diaphragm, female condom)+intrauterine device (IUD).
Distribution of clinicopathological features of cervical cancer patients and controls
#Combination: Oral pills+combined injectable contraceptives (CIC); Oral pills+condom (male) *Others: Barrier (cervical cup, diaphragm, female condom)+intrauterine device (IUD).
Correlation between
Correlation of
*Result is statistically significant (
However, in case of C509T (rs1800469) polymorphism, patients who had first degree relatives with cancer were more prone to carry the polymorphic T allele compared to the patients with no first degree relative with cancer (
Genotype frequencies of
Genotype frequencies of TGFB1 gene polymorphisms in cervical cancer patients and controls
*Result is statistically significant (p < 0.05).
Genotype frequencies of
*Result is statistically significant (
For the polymorphism C509T (rs1800469) the frequency distribution of genotypes was 42.16% CC, 45.10% CT, 12.74% TT, 57.84% CT+TT in controls and 38.81% CC, 43.28% CT, 17.91% TT, 61.19% CT+TT in patients which predicts of no statistically significant risk of cervical cancer (heterozygous, CT: OR = 1.083, 95% CI = 0.612–1.915,
In case of T869C (rs1800470) polymorphism, the frequency distribution showed similar percentage with 49.02% TT, 40.20% TC, 10.78% CC in controls and 38.81% TT, 47.01% TC, 14.78% CC in patients which predicts of no statistically significant risk of cervical cancer (heterozygous: OR = 1.309, 95% CI = 0.742–2.310,
Haplotype frequencies of
*Result is statistically significant (
In this study, we have found that there is no statistically significant correlation between polymorphisms C509T (rs1800469) and T869C (rs1800470) of
Several studies showed that polymorphisms of the
Our study has some limitations. The sample size of our study was relaively small and may lack enough power to strongly detect genotype-disease associations. Moreover, future studies in population from different ethnicity and larger sample size are required to validate our preliminary findings.
Conclusion
In conclusion, we report that C509T and T869C polymorphisms of the
Footnotes
Acknowledgments
The authors are thankful to the patients, their families, volunteers, nurses, physicians, collaborators, and scientists of the National institute of Cancer Research and Hospital (NICHR) and Bangabandhu Sheikh Mujib Medical University (BSMMU). The authors would also like to thank the Department of Clinical Pharmacy and Pharmacology, University of Dhaka, Bangladesh to provide with lab facilities and other opportunities to carry out the research work.
Conflict of interest
The authors declare no conflicts of interest.
Ethical considerations
The current study was in accordance with the declaration of Helsinki and its further amendments and the ethical committee of the participating hospital (Bangabandhu Sheikh Mujib Medical University and National Institute of cancer Health and Research, Dhaka, Bangladesh) approved the study protocol. Each patient and control subject signed an informed consent document after they were informed of the study objectives.
