The p53 codon 72 polymorphism is associated with risk and early onset of breast cancer among Saudi women

Epidemiology of cancer in Saudi Arabia thru 2010-2019: a systematic review with constrained meta-analysis

Background

Cancer is emerging as a major global health-care system challenge with a growing burden worldwide. Due to the inconsistent cancer registry system in Saudi Arabia, the epidemiology of cancer is still dispersed in the country. Consequently, this review aimed to assemble the epidemiological metrics of cancer in Saudi Arabia in light of the available published data during the period from (2010–2019).

Methods

Published literature from Saudi Arabia relating to cancer incidence, prevalence, risk factors, and other epidemiological metrics were accessed through electronic search in Medline/PubMed, Cochrane, Scopus, Web of Knowledge, Google Scholar, and public database that meet the inclusion criteria. Relevant keywords were used during the electronic search about different types of cancers in Saudi Arabia. No filters were used during the electronic searches. Data were pooled and odds ratios (ORs) and 95% confidence interval (95%CI) were calculated. A random-effects meta-analysis was performed to assess the well-determined risk factors associated with different types of cancers.

Results

The most common cancers in Saudi Arabia are breast, colorectal, prostate, brain, lymphoma, kidney and thyroid outnumbering respectively. Their prevalence rates and OR (95%CI) as follow: breast cancer 53% and 0.93 (0.84–1.00); colon-rectal cancer (CRC) 50.9% and 1.2 (0.81–1.77); prostate cancer 42.6% and 3.2 (0.88–31.11); brain/Central Nervous System cancer 9.6% and 2.3 (0.01–4.2); Hodgkin and non-Hodgkin's lymphoma 9.2% and 3.02 (1.48–6.17); kidney cancer 4.6% and 2.05 (1.61–2.61), and thyroid cancer 12.9% and 6.77 (2.34–19.53).

Conclusion

Within the diverse cancers reported from Saudi Arabia, the epidemiology of some cancers magnitude 3-fold in the latest years. This increase might be attributed to the changing in the Saudi population lifestyle (adopting western model), lack of cancer awareness, lack of screening & early detection programs, social barriers toward cancer investigations. Obesity, genetics, sedentary lifestyle, tobacco use, viral infection, and iodine & Vit-D deficiency represent the apparent cancer risk factors in Saudi Arabia.

Both p53 codon 72 Arg/Arg and pro/Arg genotypes in glioblastoma multiforme are associated with a better prognosis in bevacizumab treatment

BACKGROUND

It has previously been shown that bevacizumab, when added to chemotherapy, improved overall survival in several cancers. In glioblastoma multiforme (GBM), bevacizumab increased progression-free survival and it is widely used for tumor recurrence, though it has failed to improve overall survival (OS) in controlled trials. However, an effective biomarker for predicting the prognosis of bevacizumab treatment has yet to be identified. This study, therefore, aimed to retrospectively analyze the polymorphisms of p53 codon 72 and the clinical characteristics of GBM specimens from Taiwanese patients.

METHODS

The polymorphisms of p53 codon 72 in 99 patients with GBM treated at Taichung Veterans General Hospital in Taiwan from 2007 to 2017 were analyzed using direct DNA sequencing and PCR-RFLP analysis.

RESULTS

We found that among these GBM patients, the distribution of codon 72 polymorphisms was 28.3% for proline homozygotes (Pro/Pro), 38.4% for arginine homozygotes (Arg/Arg), and 33.3% for proline/arginine heterozygotes (Pro/Arg). Although the polymorphisms of p53 codon 72 were not directly associated with the overall survival of GBM, both the Arg/Arg and Arg/Pro genotypes were associated with significant benefits in terms of overall survival in patients treated with CCRT plus bevacizumab compared to patients treated with CCRT alone.

CONCLUSIONS

This pilot study suggests that both the Arg/Arg and Arg/Pro genotypes of p53 codon 72 polymorphism may have value as independent prognostic or predictive parameters for bevacizumab treatment response and failure. Relatedly, the results of the study further demonstrate the utility of stratifying GBM patients according to bevacizumab sensitivity.

Pathway-Affecting Single Nucleotide Polymorphisms (SNPs) in RPS6KA1 and MBIP Genes are Associated with Breast Cancer Risk

Background:

Genetic mutations and polymorphisms play an important role in the transformation of primary cells to malignant cells as it may lead to disturbance of vital pathways regulating cell cycle, DNA damage repair, and apoptosis. In this study, we genotyped single nucleotide polymorphisms (SNPs) which were predicted to affect certain pathways and to increase the risk of breast cancer.

Methods:

The study included 81 Saudi breast cancer patients and 100 matching healthy controls from the Eastern Province in Saudi Arabia. The following SNPs (rs3168891, rs2899849, rs2230394, rs2229714) were then genotyped by TaqMan genotyping assay and the allele and genotype distribution was compared.

Results:

The minor allele frequency of the following SNPs (rs3168891, rs2899849, rs2230394, rs2229714) was T=0.17, A=0.28, A=0.22, and G=0.16 respectively. The G allele of the SNP rs3168891 was significantly associated with increased breast cancer risk (P = 0.00001) while the T allele of the same locus was associated with reduced risk of breast cancer in both heterozygous and homozygous states. The T allele of SNP rs2229714 which is located in the RPS6KA1 gene was also significantly associated with the increased risk of breast cancer. However, the rs2899849 SNP located in the Integrin beta-1 (ITGB1) gene was not associated with the increased risk of breast cancer in our study population. Haplotype analysis revealed the presence of three risk haplotypes that increases the risk of breast cancer (TGGT, TGTA, GATA).

Conclusion:

We showed that three, previously untested, SNPs are associated with increased risk of breast cancer in our population. This may be added to the list of factors involved in breast cancer risk assessment studies. The benefit and the utility of the in-silico prediction of disease risk factors and their genetic association had been demonstrated in this study, yet the predicted risk alleles have to be tested in clinical studies.

Association of p53 Codon 72 Polymorphism with Breast Cancer in a Rwandese Population

BACKGROUND AND AIMS

A common polymorphism in the tumor suppressor gene p53 at codon 72 has been suggested to play a role in the development of a number of cancers. This polymorphism has been studied in many populations worldwide, with conflicting results. The present study was planned to assess the association of p53 codon 72 polymorphism with breast cancer development in a Rwandese population.

METHODS

In this study, the polymorphism was examined by allele-specific PCR analysis in 40 patients with breast cancer and 39 healthy controls.

RESULTS

The heterozygous genotype Pro/Arg prevailed in both breast cancer patients and controls, and was present in 80% (32/40) and 92.3% (36/39) of cases, respectively. No statistically significant association was observed between p53 codon 72 polymorphism and breast cancer risk. Distribution of p53 genotypes was also studied according to familial history, tumor grade, and clinical stage, and results clearly showed no statistically significant difference.

CONCLUSION

These results suggest that p53 codon 72 polymorphism could not be assessed as a risk factor marker for predisposition to breast cancer in Rwanda. However, further studies using larger sample sizes are needed to provide more conclusive results and to investigate other genetic mutations affecting the activity of p53.

RAD51 135G>C and TP53 Arg72Pro polymorphisms and susceptibility to breast cancer in Serbian women

Breast cancer is a complex disease with both genetic and environmental factors involved in its etiology. An important role of polymorphisms in genes involved in DNA repair has been reported related to breast cancer risk. We conducted a case-control study in order to investigate the association of RAD51 135G>C and TP53 Arg72Pro polymorphisms with breast cancer in Serbian women.48 BRCA negative women with breast cancer and family history of breast/ovarian cancer (hereditary group), 107 women with breast cancer but without family history of the disease (sporadic group) and 114 healthy women without a history of the disease (control group) were included. Restriction fragment length polymorphism was used for genotyping. Genotype and allelic frequencies, the odds ratio (OR) and the 95 % confidence interval (CI) were calculated as an estimate of relative risk. The Hardy-Weinberg equilibrium was tested using χ(2) test. Significance was considered for p < 0.05. RAD51 135G>C showed statistically significant association of CC genotype and increased breast cancer risk (OR 10.28, 95 % CI 1.12-94.5) in hereditary group of patients compared to the control group. Regarding the TP53 Arg72Pro, we showed statistical significance for ProPro + ProArg comparing to ArgArg (OR 2.34, 95 %, CI 1.17-4.70) in hereditary compared to sporadic group. RAD51 135G>C contributes to hereditary breast cancer in Serbian population, with CC genotype as a risk factor. We also found that carriers of Pro allele of TP53 codon 72 is related to hereditary cancer comparing to sporadic one, which indicates it as a potential risk factor for hereditary form of disease.

Individualized medicine enabled by genomics in Saudi Arabia

The biomedical research sector in Saudi Arabia has recently received special attention from the government, which is currently supporting research aimed at improving the understanding and treatment of common diseases afflicting Saudi Arabian society. To build capacity for research and training, a number of centres of excellence were established in different areas of the country. Among these, is the Centre of Excellence in Genomic Medicine Research (CEGMR) at King Abdulaziz University, Jeddah, with its internationally ranked and highly productive team performing translational research in the area of individualized medicine. Here, we present a panorama of the recent trends in different areas of biomedical research in Saudi Arabia drawing from our vision of where genomics will have maximal impact in the Kingdom of Saudi Arabia. We describe advances in a number of research areas including; congenital malformations, infertility, consanguinity and pre-implantation genetic diagnosis, cancer and genomic classifications in Saudi Arabia, epigenetic explanations of idiopathic disease, and pharmacogenomics and personalized medicine. We conclude that CEGMR will continue to play a pivotal role in advances in the field of genomics and research in this area is facing a number of challenges including generating high quality control data from Saudi population and policies for using these data need to comply with the international set up.

P53 codon 72 Arg/Pro polymorphism and lung cancer risk in Asians: an updated meta-analysis

The polymorphism of p53 codon 72, a transversion of G to C (Arg to Pro), has been demonstrated to be associated with the risk for lung cancer. However, individual studies conducted in Asians have provided conflicting and inconclusive findings. Thus, we performed a meta-analysis by pooling all currently available case–control studies to estimate the effect of p53 codon 72 Arg/Pro polymorphism on the development of lung cancer. The pooled odds ratios (ORs) with the corresponding 95 % confidence intervals (95 %CIs) were calculated to assess this effect. A total of 14 individual studies involving 7,929 cases and 5,924 controls were included into this meta-analysis according to the inclusion criteria. The overall OR for the dominant genetic model indicated that the p53 codon 72 Arg/Pro variant was positively correlated with lung cancer risk (OR_{Arg/Pro + Pro/Pro vs. Arg/Arg} = 1.14, 95 %CI 1.07–1.23, P_OR < 0.001). Similar results were found in the stratified analysis of population-based studies. The histological types of lung cancer and smoking status seemed to exert no effect on the lung cancer risk. Sensitivity analysis confirmed the stability of the above findings. The updated meta-analysis suggests that the p53 codon 72 Arg/Pro polymorphism is a risk factor for lung cancer in the Asian population. However, the potential role of gene–environment interaction in lung cancer susceptibility needs further investigation in future studies with high quality.

Association between the p53 codon 72 Arg/Pro polymorphism and hepatocellular carcinoma risk

Previous studies regarding the association of p53 codon 72 Arg/Pro polymorphism with hepatocellular carcinoma (HCC) risk have provided conflicting and inconclusive findings. Thus, a meta-analysis of all currently available publications was performed to address this issue. Eleven individual case-control studies involving a total of 2,718 cases and 3,752 controls were identified after a systematic search of the PubMed, Embase, Web of Science, and Wanfang databases. The strength of the association of p53 codon 72 Arg/Pro polymorphism with HCC risk was estimated by the pooled odds ratio (OR) with its corresponding 95 % confidence interval (95 % CI). Subgroup analyses stratified by ethnicity, source of controls, gender, hepatitis virus infection status, and family history of HCC were also conducted to assess the association. Overall, significantly increased risk of HCC was identified among carriers of the homozygous genotype ProPro (ORProPro vs. ArgArg=1.38 (95 % CI, 1.03-1.85), P OR=0.033; ORProPro vs. ArgArg + ArgPro =1.28 (95 % CI, 1.03-1.59), P OR=0.026). In subgroup analysis by ethnicity, the pooled results suggested that the p53 codon 72 Arg/Pro polymorphism was associated with an increased risk of HCC in Asians and Caucasians (for Asians, ORProPro vs. ArgArg + ArgPro=1.17 (95 % CI, 1.02-1.34), P OR=0.025; for Caucasians, ORProPro vs. ArgArg = 1.65 (95 % CI, 1.07-2.56), P OR=0.025; ORProPro vs. ArgArg + ArgPro=1.74 (95 % CI, 1.14-2.66), P OR=0.010). Subgroup analyses by source of controls and hepatitis virus infection status further demonstrated the significant association, whereas stratification factors involving gender and family history of HCC did not modify the association between p53 codon 72 Arg/Pro polymorphism and HCC risk. This meta-analysis suggests that the p53 codon 72 Arg/Pro polymorphism may play a critical role in the development of HCC, and gender and family history of HCC may not modulate the effect of p53 codon 72 Arg/Pro in HCC risk.