Combined Genetic Biomarkers Confer Susceptibility to Risk of Urothelial Bladder Carcinoma in a Saudi Population

Polymorphisms in drug-metabolizing genes and urinary bladder cancer susceptibility and prognosis: Possible impacts and future management

Epidemiological studies have shown the association of genetic variants with risks of occupational and environmentally induced cancers, including bladder (BC). The current review summarizes the effects of variants in genes encoding phase I and II enzymes in well-designed studies to highlight their contribution to BC susceptibility and prognosis. Polymorphisms in genes codifying drug-metabolizing proteins are of particular interest because of their involvement in the metabolism of exogenous genotoxic compounds, such as tobacco and agrochemicals. The prognosis between muscle-invasive and non-muscle-invasive diseases is very different, and it is difficult to predict which will progress worse. Web of Science, PubMed, and Medline were searched to identify studies published between January 1, 2010, and February 2023. We included 73 eligible studies, more than 300 polymorphisms, and 46 genes/loci. The most studied candidate genes/loci of phase I metabolism were CYP1B1, CYP1A1, CYP1A2, CYP3A4, CYP2D6, CYP2A6, CYP3E1, and ALDH2, and those in phase II were GSTM1, GSTT1, NAT2, GSTP1, GSTA1, GSTO1, and UGT1A1. We used the 46 genes to construct a network of proteins and to evaluate their biological functions based on the Reactome and KEGG databases. Lastly, we assessed their expression in different tissues, including normal bladder and BC samples. The drug-metabolizing pathway plays a relevant role in BC, and our review discusses a list of genes that could provide clues for further exploration of susceptibility and prognostic biomarkers.

Genetic Polymorphisms Involved in Bladder Cancer: A Global Review

Bladder cancer (BC) has been associated with genetic susceptibility. Single peptide polymorphisms (SNPs) can modulate BC susceptibility. A literature search was performed covering the period between January 2000 and October 2020. Overall, 334 articles were selected, reporting 455 SNPs located in 244 genes. The selected 455 SNPs were further investigated. All SNPs that were associated with smoking and environmental exposure were excluded from this study. A total of 197 genes and 343 SNPs were found to be associated with BC, among which 177 genes and 291 SNPs had congruent results across all available studies. These genes and SNPs were classified into eight different categories according to their function.

Genetic Polymorphisms of Cytochromes P450 in Finno-Permic Populations of Russia

Cytochrome P450 is an enzyme involved in the metabolism of phase 1 xenobiotics, toxins, endogenous hormones, and drugs, including those used in COVID-19 treatment. Cytochrome p450 genes are linked to the pathogenesis of some multifactorial traits and diseases, such as cancer, particularly prostate cancer, colorectal cancer, breast cancer, and cervical cancer. Genotyping was performed on 540 supposedly healthy individuals of 5 Finno-Permic populations from the territories of the European part of the Russian Federation. There was a statistically significant difference between Veps and most of the studied populations in the rs4986774 locus of the CYP2D6 gene; data on the rs3892097 locus of the CYP2D6 gene shows that Izhemsky Komis are different from the Mordovian and Udmurt populations.

Genetic susceptibility of bladder cancer in the Lebanese population

Background

Bladder cancer (BC) is the 10^th most frequent tumor worldwide. Evidence shows an association between elevated risk of BC and various single nucleotide polymorphisms (SNP). BC incidence was the highest in Lebanon according to Globocan 2018 report, but little is known about the genetic susceptibility of Lebanese people to this disease. We aim to evaluate whether this prominent incidence of BC in Lebanon is attributable to known coding genetic variants.

Methods

A case-control study was conducted at Hotel-Dieu de France Hospital, Beirut. A cohort of 51 Lebanese patients with BC were recruited between 2017 and 2020. Whole Exome Sequencing (WES) was performed on peripheral blood samples to detect coding genetic variants in the patients. An in-house database including WES data from 472 Lebanese individuals served as control. Literature review of the genetic predisposition to BC was conducted to establish a database of variants known to influence the risk of BC. In-common SNPs were identified between cases and the aforecited database, and their allelic frequencies was quantified in the former and in controls. Comparative analysis of the allelic frequencies of each in-common SNP was carried out between cases, controls, and the genome aggregation database (gnomAD). Analysis was performed by applying the binomial law and setting the p-value to 10^− 10.

Results

484 polymorphisms associated with BC were extracted from the literature review ;151 of which were in-common with the 206 939 variations detected by WES in our cases. Statistically significant differences (p-value < 10^− 10) in allelic frequencies was seen in 11 of the 151 in-common SNPs, but none of which corresponds with a higher BC risk. Moreover, rs4986782 variant in the NAT1 gene is not associated with BC in the Lebanese population. `.

Conclusion

This is the first next-generation sequencing (NGS)- based study investigating BC risk in a Lebanese cohort of 51 patients. The majority of known exonic variants in the literature were not associated with BC in our patients. Further studies with larger sample sizes are warranted to explore the association of BC in our population with known non-coding genetic variants, and the remainder of WES-generated private Lebanese variants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01372-z.

Genetic etiology and clinical challenges of phenylketonuria

This review discusses the epidemiology, pathophysiology, genetic etiology, and management of phenylketonuria (PKU). PKU, an autosomal recessive disease, is an inborn error of phenylalanine (Phe) metabolism caused by pathogenic variants in the phenylalanine hydroxylase (PAH) gene. The prevalence of PKU varies widely among ethnicities and geographic regions, affecting approximately 1 in 24,000 individuals worldwide. Deficiency in the PAH enzyme or, in rare cases, the cofactor tetrahydrobiopterin results in high blood Phe concentrations, causing brain dysfunction. Untreated PKU, also known as PAH deficiency, results in severe and irreversible intellectual disability, epilepsy, behavioral disorders, and clinical features such as acquired microcephaly, seizures, psychological signs, and generalized hypopigmentation of skin (including hair and eyes). Severe phenotypes are classic PKU, and less severe forms of PAH deficiency are moderate PKU, mild PKU, mild hyperphenylalaninaemia (HPA), or benign HPA. Early diagnosis and intervention must start shortly after birth to prevent major cognitive and neurological effects. Dietary treatment, including natural protein restriction and Phe-free supplements, must be used to maintain blood Phe concentrations of 120-360 μmol/L throughout the life span. Additional treatments include the casein glycomacropeptide (GMP), which contains very limited aromatic amino acids and may improve immunological function, and large neutral amino acid (LNAA) supplementation to prevent plasma Phe transport into the brain. The synthetic BH4 analog, sapropterin hydrochloride (i.e., Kuvan®, BioMarin), is another potential treatment that activates residual PAH, thus decreasing Phe concentrations in the blood of PKU patients. Moreover, daily subcutaneous injection of pegylated Phe ammonia-lyase (i.e., pegvaliase; PALYNZIQ®, BioMarin) has promised gene therapy in recent clinical trials, and mRNA approaches are also being studied.

Risk of Colorectal Carcinoma May Predispose to the Genetic Variants of the GST, CYP450, and TP53 Genes Among Nonsmokers in the Saudi Community

PURPOSE

Colorectal carcinoma (CRC) represents a considerable public health burden in Saudi Arabia. Several candidate genes and genetic variants have been associated with morbidity and mortality among patients with CRC. We explored whether allelic variants of the GSTM1, GSTT1, CYP450 (rs4646903 and rs1048943), and TP53 (rs1042522) genes predisposed nonsmoking Saudi individuals to increased risk for CRC.

PATIENTS AND METHODS

DNA from buccal cells of 158 participants (80 with CRC and 78 healthy controls) were analyzed for five SNPs using conventional PCR and TaqMan genotyping assays. The SNPStats software was utilized to choose the best interactive inheritance mode for selected SNPs (https://www.snpstats.net).

RESULTS

The mean age of diagnosis was 62.4±13.5 years (range, 40-83 years), with those aged 71-80 years and those aged 40-50 years accounting for the most diagnoses (35.7% and 28.6% of diagnosis, respectively). The GSTM1 and TP53 rs1042522 SNPs were associated with CRC (OR= 3.7; P< 0.0001, and OR= 1.6; P= 0.033, respectively). A plausible contribution to CRC was observed for the GSTM1 and TP53 rs1042522 SNPs (x ² _Yates= 14.7; P= 0.00013, and x ² _Yates= 11.2; P= 0.0008, respectively), while the GSTT1 null variant did not affect risk. Heterozygosity in the CYP450 (rs4646903 and rs1048943 SNPs) was associated with a significant risk for CRC. The GSTM1/GSTT1 and CYP450 rs4646903/rs1048943 SNP pairs were in linkage disequilibrium, and the associations were statistically significant (P= 0.01 and P= 4.6x10^‒7, respectively).

CONCLUSION

The GSTM1 and TP53 rs1042522 variants can increase the development of CRC in Saudi nonsmokers. Even the presence of one copy of a variant allele in the CYP1A1 gene can predispose CRC risk. Additional studies should also examine other SNP combinations with lifestyle factors that may help prevent, rather than facilitate, colorectal tumorigenesis.

Impact of Long Non-Coding RNA HOTAIR Genetic Variants on the Susceptibility and Clinicopathologic Characteristics of Patients with Urothelial Cell Carcinoma

Increasing evidence shows that dysregulated expression of long non-coding (lnc)RNAs can serve as diagnostic or prognostic markers in urothelial cell carcinoma (UCC), the most common pathological type of bladder cancer. lncRNA HOX transcript antisense RNA (HOTAIR) was shown to promote tumor progression and be associated with a poor prognosis in multiple cancers including bladder cancer. Polymorphisms of HOTAIR were recently linked to a predisposition for diverse malignancies. Herein we conducted a case-control study to evaluate whether genetic polymorphisms of HOTAIR were associated with UCC risk and clinicopathologic characteristics. Four loci (rs920778 T>C, rs1899663 G>T, rs4759314 A>G, and rs12427129, C>T) of HOTAIR were genotyped by a TaqMan allelic discrimination method in 431 cases and 862 controls. We found that female patients who carried AG + GG genotype of rs4759314 were associated with an increased UCC risk after controlling for age and tobacco consumption (adjusted odds ratio (AOR) = 1.92, 95% confidence interval (CI): 1.01–3.64, p = 0.047) and a lower overall survival rate (p = 0.008). Moreover, patients with a smoking habit or younger age (≤65 years), who had at least one T allele of HOTAIR rs12427129 were at a higher risk of developing advance tumor T satge (p = 0.046), compared to those patients with CC homozygotes. In contrast, rs920778 C allele carriers were negatively correlated with the development of lymph node metastasis (OR = 0.51, 95% CI: 0.28–0.94, p = 0.031). Further analyses of clinical datasets revealed correlations of the expression of HOTAIR with tumor metastasis and a poor survival rate in patients with UCC. Our results verified the diverse impacts of HOTAIR variants on UCC susceptibility and clinicopathologic characteristics.

Association of Glutathione S-transferase gene polymorphism with bladder Cancer susceptibility

BACKGROUND

We conducted a meta-analysis to evaluate the relationship between the glutathione S-transferase μ1 (GSTM1)- and glutathione S-transferase θ1 (GSTT1)- null genotypes and susceptibility to bladder cancer.

METHODS

We identified association reports from the databases of PubMed, Embase, the Cochrane Library and the China Biological Medicine Database (CBM disc) on July 1, 2017 and synthesized eligible investigations. Results were expressed using odds ratios (ORs) for dichotomous data, and we also calculated 95% confidence intervals (CIs).

RESULTS

In this meta-analysis, we found that the GSTM1-null genotype was associated with bladder cancer risk in the overall population, and individually in whites, Africans and Asians (overall population: OR = 1.40, 95% CI: 1.31-1.48, P<0.00001; whites: OR = 1.39, 95% CI: 1.26-1.54, P<0.00001; Africans: OR = 1.54, 95% CI: 1.16-2.05, P = 0.003; Asians: OR = 1.45, 95% CI: 1.33-1.59, P<0.00001). The GSTT1-null genotype was associated with bladder cancer risk in the overall population, but not in whites, in Africans or Asians (overall population: OR = 1.11, 95% CI: 1.01-1.22, P = 0.03; whites: OR = 1.16, 95% CI: 0.99-1.36, P = 0.07; Africans: OR = 1.07, 95% CI: 0.65-1.76, P = 0.79; Asians: OR = 1.05, 95% CI: 0.91-1.22, P = 0.51). Interestingly, a dual-null GSTM1-GSTT1 genotype was associated with bladder cancer risk in the overall population and in Asians (overall population: OR = 1.48, 95% CI: 1.15-1.92, P = 0.002; Asians: OR = 1.62, 95% CI: 1.15-2.28, P = 0.006). In conclusion, the GSTM1-null, GSTT1-null and dual-null GSTM1-GSTT1 genotypes might be associated with the onset of bladder cancer, but additional genetic-epidemiological studies should be conducted to explore this association further.

TP53 codon 72 Polymorphism and bladder cancer risk: a meta-analysis and emphasis on the role of tumor or smoking status

Background: Various studies had explored the relationship between TP53 codon 72 polymorphisms and the risk of bladder cancer (BC). However, their results remained inconsistent and the definite role of smoking or tumor status associated with this polymorphism in BC cases was seldom involved. Hence, this meta-analysis was to disclose such associations. Methods: Systematical and comprehensive retrieval of online databases PubMed, PMC, EMBASE and Web of Science were conducted to obtain eligible studies, up to May 30th, 2018. Pooled odds ratios (ORs) with 95% confidence intervals (CI) were utilized to assess the associations between TP53 codon 72 polymorphisms and BC susceptibilities under five genetic comparison models. Results: Ultimately, this meta-analysis enrolled 22 applicable studies with 3,791 BC cases and 4,917 controls. Our results suggested that the variant genotypes were associated with BC risk in Asian subgroup (allele model: OR=1.19, 95% CI=1.04-1.34; dominant model: OR=1.27, 95% CI=1.06-1.52; homozygote model: OR=1.36, 95% CI=1.03-1.80), while negative outcomes were presented in Caucasians. In the relationship between TP53 codon 72 polymorphisms and BC tumor stage in Asian group, positive results were presented in allele model: OR=1.68, 95% CI=1.04-2.72; dominant model: OR=2.46, 95% CI=1.08-5.61; heterozygous model: OR=2.32, 95% CI=1.04-5.14; homozygote model: OR=2.66, 95% CI=1.04-6.81. However, no evidence was revealed between this polymorphism and BC tumor grade. Besides, significant associations were displayed between TP53 codon 72 polymorphism and smoking status (allele model: OR=1.40, 95% CI=1.06-1.84; dominant model OR=1.72, 95% CI=1.18-2.50; heterozygous model: OR=1.77, 95% CI=1.19-2.64). Conclusion: Taken together, our results shed light on that TP53 codon 72 polymorphism was significantly associated with the susceptibility to BC in Asians. In addition, positive associations were also revealed between this polymorphism and tumor stage/smoking status in BC cases.

Molecular characterization of exonic rearrangements and frame shifts in the dystrophin gene in Duchenne muscular dystrophy patients in a Saudi community

BACKGROUND

In individuals with Duchenne muscular dystrophy (DMD), exon skipping treatment to restore a wild-type phenotype or correct the frame shift of the mRNA transcript of the dystrophin (DMD) gene are mutation-specific. To explore the molecular characterization of DMD rearrangements and predict the reading frame, we simultaneously screened all 79 DMD gene exons of 45 unrelated male DMD patients using a multiplex ligation-dependent probe amplification (MLPA) assay for deletion/duplication patterns. Multiplex PCR was used to confirm single deletions detected by the MLPA.

RESULTS

There was an obvious diagnostic delay, with an extremely statistically significant difference between the age at initial symptoms and the age of clinical evaluation of DMD cases (t value, 10.3; 95% confidence interval 5.95-8.80, P < 0.0001); the mean difference between the two groups was 7.4 years. Overall, we identified 147 intragenic rearrangements: 46.3% deletions and 53.7% duplications. Most of the deletions (92.5%) were between exons 44 and 56, with exon 50 being the most frequently involved (19.1%). Eight new rearrangements, including a mixed deletion/duplication and double duplications, were linked to seven cases with DMD. Of all the cases, 17.8% had duplications with no hot spots. In addition, confirmation of the reading frame hypothesis helped account for new DMD rearrangements in this study. We found that 81% of our Saudi patients would potentially benefit from exon skipping, of which 42.9% had a mutation amenable to skipping of exon 51.

CONCLUSIONS

Our study could generate considerable data on mutational rearrangements that may promote future experimental therapies in Saudi Arabia.

Molecular characterization of exonic rearrangements and frame shifts in the dystrophin gene in Duchenne muscular dystrophy patients in a Saudi community

BACKGROUND

In individuals with Duchenne muscular dystrophy (DMD), exon skipping treatment to restore a wild-type phenotype or correct the frame shift of the mRNA transcript of the dystrophin (DMD) gene are mutation-specific. To explore the molecular characterization of DMD rearrangements and predict the reading frame, we simultaneously screened all 79 DMD gene exons of 45 unrelated male DMD patients using a multiplex ligation-dependent probe amplification (MLPA) assay for deletion/duplication patterns. Multiplex PCR was used to confirm single deletions detected by the MLPA.

RESULTS

There was an obvious diagnostic delay, with an extremely statistically significant difference between the age at initial symptoms and the age of clinical evaluation of DMD cases (t value, 10.3; 95% confidence interval 5.95-8.80, P < 0.0001); the mean difference between the two groups was 7.4 years. Overall, we identified 147 intragenic rearrangements: 46.3% deletions and 53.7% duplications. Most of the deletions (92.5%) were between exons 44 and 56, with exon 50 being the most frequently involved (19.1%). Eight new rearrangements, including a mixed deletion/duplication and double duplications, were linked to seven cases with DMD. Of all the cases, 17.8% had duplications with no hot spots. In addition, confirmation of the reading frame hypothesis helped account for new DMD rearrangements in this study. We found that 81% of our Saudi patients would potentially benefit from exon skipping, of which 42.9% had a mutation amenable to skipping of exon 51.

CONCLUSIONS

Our study could generate considerable data on mutational rearrangements that may promote future experimental therapies in Saudi Arabia.