Tissue hOGG1 genotype predicts bladder cancer prognosis: a novel approach using a peptide nucleic acid clamping method

Decrease in skeletal muscle index 1 year after radical cystectomy as a prognostic indicator in patients with urothelial bladder cancer

PURPOSE

The present study aimed to determine whether sarcopenia after radical cystectomy (RC) could predict overall survival (OS) in patients with urothelial bladder cancer (UBC).

MATERIALS AND METHODS

The lumbar skeletal muscle index (SMI) of 80 patients was measured before and 1 year after RC. The prognostic signifi cance of sarcopenia and SMI decrease after RC were evaluated using Kaplan-Meier analysis and a multivariable Cox regression model.

RESULTS

Of 80 patients, 26 (32.5%) experienced sarcopenia before RC, whereas 40 (50.0%) experienced sarcopenia after RC. The median SMI change was -2.2 cm2/m2. Patients with sarcopenia after RC had a higher pathological T stage and tumor grade than patients without sarcopenia. Furthermore, the overall mortality rate was signifi - cantly higher in patients with sarcopenia than in those without sarcopenia 1 year after RC. The median follow-up time was 46.2 months, during which 22 patients died. Kaplan-Meier estimates showed a signifi cant difference in OS rates based on sarcopenia (P=0.012) and SMI decrease (P=0.025). Multivariable Cox regression analysis showed that SMI decrease (≥2.2 cm2/m2) was an independent predictor of OS (hazard ratio: 2.68, confi dence interval: 1.007-7.719, P = 0.048).

CONCLUSIONS

The decrease in SMI after surgery might be a negative prognostic factor for OS in patients who underwent RC to treat UBC.

Association of hOGG1 Ser326Cys, ITGA2 C807T, TNF-A -308G>A and XPD Lys751Gln polymorphisms with the survival of Malaysian NPC patients

Background

Nasopharyngeal carcinoma is a rare form of cancer across the world except in certain areas such as Southern China, Hong Kong and Malaysia. NPC is considered a relatively radiosensitive tumor and patients diagnosed at early stages tend to survive longer compared to those with advanced disease. Given that early symptoms of NPC are non-specific and that the nasopharynx is relatively inaccessible, less invasive screening methods such as biomarker screening might be the key to improve NPC survival and management. A number of genes with their respective polymorphisms have been shown in past studies to be associated with survival of various cancers. hOGG1 and XPD genes encode for a DNA glycosylase and a DNA helicase respectively; both are proteins that are involved in DNA repair. ITGA2 is the alpha subunit of the transmembrane receptor integrin and is mainly responsible for cell-cell and cell-extracellular matrix interaction. TNF-α is a cytokine that is released by immune cells during inflammation.

Methods

Restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) was used to genotype all the aforementioned gene polymorphisms. Kaplan-Meier survival function, log-rank test and Cox regression were used to investigate the effect of gene polymorphisms on the all-cause survival of NPC.

Results

NPC cases carrying T/T genotype of ITGA2 C807T have poorer all-cause survival compared to those with C/C genotypes, with an adjusted HR of 2.06 (95% CI = 1.14–3.72) in individual model. The 5-year survival rate of C/C carriers was 55% compared to those with C/T and T/T where the survival rates were 50% and 43%, respectively.

Conclusion

The finding from the present study showed that ITGA2 C807T polymorphism could be potentially useful as a prognostic biomarker for NPC. However, the prognostic value of ITGA2 C807T polymorphism has to be validated by well-designed further studies with larger patient numbers.

The hOGG1 Ser326Cys gene polymorphism and susceptibility for bladder cancer: a meta-analysis

Objective:

To assess the susceptibility of the hOGG1 genetic polymorphism for bladder cancer and evaluate the impact of smoking exposure.

Materials and Methods:

Articles included in PubMed, Medline and Springer databases were retrieved using the following key words: “human 8-oxoguanine DNA glycosylase”, “OGG”, “OGG1”, “hOGG1”, “genetic variation”, “polymorphism” , “bladder cancer”, and “bladder carcinoma” to Meta-analysis was performed to detect whether there were differences between the bladder cancer group and the control group about the distribution of genotypes of the hOGG1 gene.

Results:

The results showed that there are no significant associations between the hOGG1 326Cys polymorphism and bladder cancer: GG vs. CC (OR: 1.09, 95% CI: 0.85–1.40, p=0.480); GC vs. CC (OR: 1.05, 95% CI: 0.85–1.28, p=0.662); GG+GC vs. CC (OR: 1.04, 95% CI: 0.89–1.21, p=0.619); GG vs. GC+CC(OR: 1.02, 95% CI: 0.78–1.33, p=0.888); G vs. C (OR: 1.01, 95% CI: 0.91–1.13, p=0.818). In the smoker population, no significant associations between the hOGG1 326Cys polymorphism and bladder cancer were observed for all the models. However, individuals carrying the hOGG1 Cys326Cys genotype have increased risk for bladder cancer compared to those carrying the hOGG1 Ser326Ser genotype in the non-smoker Asian population.

Conclusion:

The hOGG1 326Cys polymorphisms aren't a risk factor for bladder cancer, especially in the smoker population. But GG genotype is a risk factor for bladder cancer to the non-smoker Asian population compared with CC genotype.

The Cellular Response to Oxidatively Induced DNA Damage and Polymorphism of Some DNA Repair Genes Associated with Clinicopathological Features of Bladder Cancer

Genome instability and impaired DNA repair are hallmarks of carcinogenesis. The study was aimed at evaluating the DNA damage response in H2O2-treated lymphocytes using the alkaline comet assay in bladder cancer (BC) patients as compared to clinically healthy controls, elderly persons, and individuals with chronic inflammations. Polymorphism in DNA repair genes involved in nucleotide excision repair (NER) and base excision repair (BER) was studied using the PCR-RFLP method in the Belarusian population to elucidate the possible association of their variations with both bladder cancer risk and clinicopathological features of tumors. The increased level of H2O2-induced DNA damage and a higher proportion of individuals sensitive to oxidative stress were found among BC patients as compared to other groups under study. Heterozygosity in the XPD gene (codon 751) increased cancer risk: OR (95% CI) = 1.36 (1.03-1.81), p = 0.031. The frequency of the XPD 312Asn allele was significantly higher in T ≥ 2 high grade than in T ≥ 2 low grade tumors (p = 0.036); the ERCC6 1097Val/Val genotype was strongly associated with muscle-invasive tumors. Combinations of homozygous wild type alleles occurred with the increased frequency in patients with non-muscle-invasive tumors suggesting that the maintenance of normal DNA repair activity may prevent cancer progression.

Orphan nuclear receptor HNF4G promotes bladder cancer growth and invasion through the regulation of the hyaluronan synthase 2 gene

Nuclear receptors (NRs) are a class of transcription factors that are closely involved in the progression of certain types of cancer. We aimed to study the relation between bladder cancer and NRs, with special focus on orphan NRs whose ligands and functions have not been identified. First, we examined the expression levels of 22 genes encoding orphan NRs in clinical bladder cancer and found that hepatocyte nuclear factor 4γ (HNF4G; NR2A2) and NR2F6 were the genes that were upregulated most frequently in cancer tissues compared with their paired normal tissues. Knockdown and overexpression of each of these orphan NRs suppressed and stimulated the growth of bladder cancer cells in vitro, respectively. HNF4G also promoted tumor growth in bladder cancer xenograft models in vivo. Furthermore, HNF4G was both necessary and sufficient for the invasion of bladder cancer cells in vitro. Moreover, using microarray analyses, we identified hyaluronan synthase 2 (HAS2) as one of the genes induced by HNF4G in bladder cancer cells. Transcription was activated by HNF4G in reporter assays using the promoter/enhancer region of the HAS2 gene. The endogenous expression of the HAS2 gene was suppressed by knockdown of HNF4G. In turn, knockdown of HAS2 inhibited the growth and invasion of bladder cancer cells. Taken together, our data suggest that some orphan NRs are involved in bladder cancer progression and that, among them, HNF4G promotes the growth and invasion of bladder cancer, at least in part, via the regulation of the HAS2 gene.

hOGG1 Ser326Cys polymorphism is associated with risk of bladder cancer in a Chinese population: a case-control study

Human oxoguanine glycosylase 1 (hOGG1) is a DNA repair enzyme, which plays important roles in the base excision repair (BER) pathway. Several studies reported a common polymorphism Ser326Cys (rs1052133) in hOGG1, which conferred the susceptibility of bladder cancer. We hypothesized that the polymorphism is associated with risk of bladder cancer in a Chinese population. In a case-control study of 1050 histologically confirmed bladder cancer patients and 1404 age and sex matched healthy controls, we genotyped the hOGG1 Ser326Cys polymorphism using TaqMan technology and assessed its association with bladder cancer risk. We found that the hOGG1 Ser/Cys + Ser/Ser genotypes were associated with a significantly increased risk of bladder cancer (adjusted odds ratio [OR] = 1.19, 95% confidence interval [CI] = 1.01-1.41), compared with the Cys/Cys genotype. Furthermore, the increased risk was more pronounced among subjects over age 65 years (OR = 1.31, 95% CI = 1.04-1.66), male subjects (OR = 1.21, 95% CI = 1.00-1.47), ever smokers (OR = 1.29, 95% CI = 1.00-1.68) and heavy smokers (>20 pack-years) (OR = 1.45, 95% CI = 1.03-2.04). No significant association was observed in the stratification of tumor grade and tumor stage for bladder cancer. In conclusion, our results suggest that hOGG1 Ser326Cys polymorphism may contribute to the susceptibility to bladder cancer in a Chinese population.

Biomarkers for prognosis and treatment selection in advanced bladder cancer patients

PURPOSE OF REVIEW

Patients with locally 'advanced' or muscle invasive bladder cancer have higher mortality rates than patients with nonmuscle invasive ('superficial') bladder cancer. Biomarkers can stratify clinical outcomes and thus promise to more accurately prognosticate and thus help assign patients to the appropriate treatments. The aim of this review is to summarize biomarker developments in the past year and to discuss their implications in prognosis and treatment selection in locally advanced bladder cancer.

RECENT FINDINGS

Prognostic biomarkers for bladder cancer are identified at the DNA, RNA and/or protein levels. Some are new markers, whereas others are established markers with new roles in bladder cancer. Markers can report on the risk of disease recurrence or metastasis, or treatment responsiveness and thus are useful in determining 'who to treat' and 'what to treat with'.

SUMMARY

The list of biomarkers for prognosis and treatment selection for advanced bladder cancer is growing. For most, their clinical relevance is unclear due to their lack of validation in external datasets. MicroRNAs and new techniques including next-generation sequencing offer additional opportunities for biomarker discovery, validation, and clinical applications.