Dinesh Ahirwar

Do DNA repair genes OGG1, XRCC3 and XRCC7 have an impact on susceptibility to bladder cancer in the North Indian population?

OBJECTIVE Polymorphisms in DNA repair genes may be associated with altered DNA repair capacity, thereby influencing an individuals susceptibility to smoking-related cancers such as bladder cancer. Therefore, we sought to examine the correlation between single nucleotide polymorphisms in DNA repair genes and bladder cancer. METHODOLOGY We undertook a case-control study of 212 urothelial bladder cancer (UBC) cases and 250 controls to investigate the association between OGG1 (C1245G rs1052133), XRCC3 (C18067T, rs861539) and XRCC7 (G6721T, rs7003908) polymorphisms and bladder cancer susceptibility by PCR-RFLP and the ARMS method. We also investigated gene-environment interactions. RESULTS The OGG1 GG genotype was associated with an elevated risk of urothelial bladder cancer (UBC) (OR, 2.10; p, 0.028). XRCC7 + 6721 GG was also associated with increased susceptibility to UBC (OR, 4.45; p, 0.001). In a recessive model, the OGG1 GG genotype showed an increased risk of TaG(2,3) + T1G(1-3) tumors. Additionally, the OGG1 GG genotype in non-smokers represented a 2.46-fold greater risk (OR, 2.46; p, 0.035) in bladder cancer patients. Subsequent analysis demonstrated more pronounced association of XRCC7 with smokers (OR, 4.39; p, 0.001). XRCC7 also showed increased association with TaG(2,3) + T1G(1-3) tumors and muscle invasive tumors (OR, 3.16; p, 0.001 and OR, 4.24; p, 0.001, respectively). Multiple Cox regression analysis in non-muscle invasive bladder tumor (NMIBT) patients demonstrated an association of the OGG1 GG polymorphism with a high risk of recurrence in patients on cystoscopic surveillance (HR, 4.04; p, 0.013). Subsequently, shorter recurrence-free survival (log rank p, 0.024; CC/GG, 42/24) was observed. CONCLUSION Our data suggest association of a variant (GG) genotype of OGG1 with increased UBC susceptibility and a high risk of tumor recurrence in NMIBT patients on cystoscopic surveillance. XRCC7 G allele carriers (TG+GG) are also at an elevated risk for susceptibility to UBC as evidenced by a high odds ratio throughout the analysis.

Anti- and proinflammatory cytokine gene polymorphism and genetic predisposition: association with smoking, tumor stage and grade, and bacillus Calmette-Guérin immunotherapy in bladder cancer

Cytokines mediate many immune and inflammatory responses contributing to tumorigenesis. The present study evaluated polymorphisms of IL4, IL6, and TNF (previously TNFA) genes influencing risk in development of transitional cell carcinoma of bladder and recurrence after bacillus Calmette-Guérin (BCG) immunotherapy. The study included 136 unrelated histopathologically confirmed cases and 200 population-based controls. Genomic DNA was extracted from peripheral leukocytes and genotyped for polymorphism in IL4 intron 3, with point mutations identified by amplification refractory mutation system polymerase chain reaction (ARMS-PCR) in IL6-174 G/C and by PCR-restriction fragment length polymorphism analysis in TNF-308 G/A. The IL6 variant C/C exhibited significant association with bladder cancer risk (odds ratio OR = 2.811, P = 0.004), but IL4 and TNF genetic variants did not. Significant association was observed for IL4 (B1/B2+B2/B2) with high-grade or late-stage tumor for TaG3+T1 and T2+ (OR = 5.950, and 6.342 respectively) and with smoking (P = 0.004, OR = 4.202). Low recurrence risk was observed in BCG-treated patients carrying C/C genotype of IL6 (hazard ratio = 0.298, P = 0.03), and also higher recurrence-free survival (log rank P = 0.021). TNF and IL4 demonstrated no association of bladder cancer risk and BCG therapy. The low-producing variant C/C of IL6 may be a risk factor for bladder cancer, whereas high-producing genotypes of IL4 (B1/B2+B2/B2) may predispose to higher risk in patients with high-grade or late-stage tumor and smoking habits. The low-producing C/C IL6 genotype, which favors Th1 response, may be a beneficial prognostic indicator for treatment and survival of BCG-treated patients.

Cytokine gene polymorphisms are associated with risk of urinary bladder cancer and recurrence after BCG immunotherapy

The association of interleukin-1β (IL-1B) -511C > T and IL-1 receptor antagonist (IL-1RN) VNTR, transforming growth factor-β (TGF-B1) +28C > T and interferon-γ (IFN-G) + 874T>A polymorphisms with bladder cancer (CaB) susceptibility and risk of recurrence in Bacillus Calmette–Guérin (BCG)-treated patients was analyzed in 287 controls and 213 CaB patients (73 BCG treated). Increased risk was observed with the IL-1RN*2 allele (odds ratio (OR) 5.01) and the IFN-G +874 A allele (OR 1.78). TGF-B TT and IFN-G +874 A carriers were associated with reduced (hazard ratio (HR) 0.37) and enhanced (HR 2.24) risk of recurrence after BCG immunotherapy, respectively. The study suggests that cytokine gene variants may modulate CaB susceptibility and risk of recurrence after BCG immunotherapy.

XRCC1 codon 399 mutant allele: A risk factor for recurrence of urothelial bladder carcinoma in patients on BCG immunotherapy

XRCC1 protein plays crucial role in base excision repair (BER) by acting as a scaffold for other BER enzymes. Variants in XRCC1 gene might alter protein structure/function or create alternatively spliced protein influencing BER efficiency and affect individual susceptibility/recurrence to urinary bladder cancer (BC). We tested whether polymorphisms in XRCC1 gene were associated with BC risk and further to substantiate risk of recurrence after Bacillus Calmette-Guerin (BCG) immunotherapy. Genotyping for three polymorphic sites of XRCC1 gene at codon Arg194Trp (PvuII), Arg280His (RsaI) and, Arg399Gln (MspI) in 140 BC cases and 190 controls by PCR-RFLP method was done. We observed significant association in heterozygous genotype (GA) of codon 280 and 399 with BC risk (OR=1.96, p=0.021 and OR = 1.81, p=0.021, respectively), however no association was seen for variant AA genotype. A trend of increased risk with high stage and grade in patients with codon 194 variant genotypes (CT+TT) was observed. Haplotype analysis showed that individuals with haplotype 194C-280G-399A were at >3-fold higher risk for BC (OR=3.48, p=0.01). The A/A genotype of codon 399 was associated with high risk for recurrence in BCG treated patients (HR=5.05, P=0.01) thus, showing reduced recurrence free survival (AA/GG=12/60months; log rank P=0.004). The study suggested no association of variant genotypes with the susceptibility to BC. Haplotype analysis however, revealed that XRCC1 399 A allele may have a major role as patients with haplotype 194C-280G-399A carrying variant allele of 399 were at higher risk. Running Title XRCC1 gene polymorphism and risk of recurrence after BCG immunotherapy

IL-8 -251 T > A polymorphism is associated with bladder cancer susceptibility and outcome after BCG immunotherapy in a northern Indian cohort.

BACKGROUND AND AIMS Chemokines and transcription factor NF-kappaB play a pivotal role in development of carcinoma of the bladder (CaB). The present study was conducted to analyze the association of chemokines IL-8 -251 T>A and +678 C>T and NF-kappaB -94 (ATTG) insertion/deletion polymorphisms with the risk of CaB and outcome after bacillus Calmette-Guerin (BCG) immunotherapy in a cohort of northern India. METHODS Histologically confirmed 205 CaB cases and 270 controls were included. Of these, 71 patients were treated with BCG immunotherapy. Genotyping was done using allele-specific PCR methodology. RESULTS The variant genotype (AA) of IL-8 -251 polymorphism was associated with more than 2-fold risk of CaB (OR 2.12; p = 0.003; 95% CI 1.28-3.52). None of the other genotypes showed association with CaB risk. Subsequently, the diplotype -251A/+678T demonstrated a 1.8-fold increased risk for CaB (OR 1.84, 95% CI 1.37-2.47). Furthermore, -251 AA genotypes reduced the risk of recurrence after BCG immunotherapy (AA; HR 0.12; 95% CI 0.04-0.41). Subsequently, improved recurrence-free survival (mean recurrence-free survival for GG, GA and AA genotypes was 24, 39 and 53 months respectively). Similarly, NF-kappaB ATTG Ins/Ins genotype was at reduced risk of recurrence after BCG treatment compared to Del/Del genotype, which exhibited a 2.5-fold increased risk of recurrence in patients treated with BCG immunotherapy (HR, 2.53; 95% CI 1.00-6.36). Subsequently, mean recurrence-free survival (Ins/Ins, 41; Ins/Del, 44 and Del/Del, 10 months; log rank, 0.030). CONCLUSIONS Our results suggested that the IL-8 -251 T>A polymorphism may be a relevant host susceptibility factor for bladder carcinoma development and may influence outcome after BCG immunotherapy. Similarly, NF-kappaB ATTG polymorphism may also modify risk-free survival of BCG-treated patients.

Gene variants of XRCC4 and XRCC3 and their association with risk for urothelial bladder cancer

The DNA double strand break repair gene XRCC4, an important caretaker of genome stability and XRCC3 are suggested to play an imperative role in the development of carcinogenesis. However, no evidence has been provided showing that these genes are associated with risk of urinary bladder cancer (UBC). The study was designed to examine the polymorphisms associated with two genes namely XRCC4 G1394T (rs6869366), intron 3 (rs28360317), intron 7 rs1805377 and rs2836007 and XRCC3 (rs861539 and rs1799796), respectively and investigate their role as susceptible markers for UBC risk in North Indian cohort. In this hospital-based case–control study histologically confirmed 211 UBC patients and 244 age and gender matched controls of similar ethnicity were genotyped by means of PCR-RFLP. Significant different distributions in the frequency of the XRCC4 intron 3 genotype, but not the XRCC4 G1394T or intron 7 genotypes, between the UBC and control groups were observed. XRCC4 intron 7 Del/Del conferred enhanced risk (OR 1.94; P 0.017) in UBC. Interestingly, XRCC −1394 G>T variant genotype GG was associated with reduced risk (OR 0.27; P 0.020). However, none of the four polymorphisms in XRCC4 were associated with tobacco smoking and risk of recurrence in patients treated with BCG immunotherapy. Similarly, none of the XRCC3 polymorphisms were associated with UBC susceptibility. Our results suggested that the XRCC4 intron 3 rs6869366 genotype and intron 7 rs28360317 may be associated with UBC risk and may be a novel useful marker for primary prevention and anticancer intervention.

Influence of XPD and APE1 DNA Repair Gene Polymorphism on Bladder Cancer Susceptibility in North India

OBJECTIVES To explore the association between xerodema pigmentosum group D (XPD) Asp(312)Asn and Lys(751)Gln and apurinic apyrimidic endonuclease 1 (APE1) Asp(148)Glu gene polymorphism and risk of bladder cancer (BC) susceptibility. METHODS This hospital-based case-control study included 206 patients with newly diagnosed bladder transitional cell carcinoma and 250 cancer-free controls who had been frequency matched by age, sex, and ethnicity. Polymorphisms in XPD Asp(312)Asn and Lys(751)Gln and APE1 Asp(148)Glu gene using polymerase chain reaction-restriction fragment length polymorphism and amplification refractory mutation system were genotyped. RESULTS The XPD Asp(312)Asn AA genotype was associated with an elevated risk of BC (odds ratio [OR] 3.30, P = .001.) The AA genotype was significantly associated with nonmuscle-invasive BC (OR 4.62, corrected P = .003). Both the heterozygous GA and the homozygous AA was associated with a greater risk of low-grade (grade 1) BC (OR 2.51, corrected P = .006 and OR 5.21, corrected P = .003, respectively). The APE1 GG genotype showed a decreased risk of BC (OR 0.27, P = .027.) Haplotype AC (codon 312A-codon 751C) of XPD demonstrated an association with a greater susceptibility to BC (OR 2.16, correct P = .0008). CONCLUSIONS Reduced DNA repair capacity due to XPD Asp(312)Asn AA genotype might be a risk factor for BC. The AA genotype predisposed to a greater risk at the initial stage and grade of BC. The APE1 148GG genotype conferred a protective association with BC susceptibility.

Association of tumour necrosis factor‐α gene (T‐1031C, C‐863A, and C‐857T) polymorphisms with bladder cancer susceptibility and outcome after bacille Calmette‐Guérin immunotherapy

To investigate the association of tumour necrosis factor‐α gene (TNF‐α) polymorphisms T‐1031C, C‐863A, and C‐857T with bladder cancer risk and recurrence after bacille Calmette‐Guérin (BCG) immunotherapy, as TNF‐α regulates inflammatory process influencing bladder cancer susceptibility and outcome of BCG immunotherapy.

Association between −174 G/C Promoter Polymorphism of the Interleukin-6 Gene and Progression of Prostate Cancer in North Indian Population

The cellular alterations that give rise to cancer initiate changes in cytokine expression. Though IL-6 is known to play a major role in proliferation of tumor cells, IL-4 upregulates androgen receptors and prostate-specific antigen (PSA). The present study was undertaken to evaluate the association of IL-4 and IL-6 gene polymorphisms for the susceptibility to prostate cancer (PCa) risk. Our study included 200 controls and 200 histologically confirmed cases of PCa. Polymorphisms in IL-4 (intron 3, by VNTR analysis) and IL-6 (-174 G/C, by amplification refractory mutation system, i.e., ARMS-PCR) were genotyped in all the subjects. There was no significant association of IL-4 and IL-6 gene polymorphisms with the risk of PCa. Nevertheless, twofold risk with progression to bone metastasis (odds ratio = 2.09; 95% confidence interval = 1.16-3.75; p = 0.014) in PCa patients was observed. No association with other confounding factors such as PSA level, Gleason score, and lifestyle-associated risk factors like tobacco chewing and cigarette smoking was seen. Our study suggests that an IL-6 gene variant may be associated with prostate progression and bone metastasis.

Interleukin-10 G-1082A and C-819T polymorphisms as possible molecular markers of urothelial bladder cancer.

BACKGROUND AND AIMS Interleukin-10 (IL-10) is an immunosuppressive cytokine that may promote tumor growth and metastasis in later stages of cancer development. DNA sequence variations in IL-10 gene may lead to altered production and/or activity, and this can modulate an individuals susceptibility to urothelial bladder cancer (UBC). To test this hypothesis, we investigated the association of rs 1800896 and rs 3021097 polymorphisms in IL-10 gene and their haplotypes with the risk of UBC in a Northern Indian population. METHODS We analyzed two single nucleotide polymorphisms of IL-10 gene at G-1082A (rs 1800896) and C-819T (rs 3021097) in 214 histologically confirmed UBC patients and 385 matched controls by allele-specific polymerase chain reaction (AS-PCR). RESULTS IL-10 C-819T CT, TT genotypes and T carriers (CT + TT) had significant association with UBC susceptibility (OR 1.75, 95% CI 1.09-2.80; OR 1.81, 95% CI 1.09-3.01 and OR 1.77, 95% CI 1.14-2.75, respectively). Similarly, GA, AA genotypes and A carriers (G-1082A) demonstrated increased risk for UBC (OR 1.91, 95% CI 1.04-3.50; OR 2.01, 95% CI 1.08-3.74 and OR 1.95, 95% CI 1.09-3.50, respectively). TT (C-819T) and T carriers showed protective association with high-risk tumors; (OR 0.34, 95% CI 0.13-0.88 and OR 0.41, 95% CI 0.17-0.97, respectively). We did not observe any association of IL-10 polymorphisms with smoking habits and UBC risk. CONCLUSIONS The study suggested that the low-producing genotypes of IL-10 (C-819T and G-1082A) polymorphisms are associated with increased UBC risk. Individuals with (C-819T) TT genotype and T carriers, however, showed a protective association with high-risk tumors. Our data suggest that IL-10 G-1082A and C-819T polymorphisms may be used as a molecular marker of urothelial bladder cancer.