Genetic polymorphism of glutathione S-transferase T1 and the risk of colorectal cancer: A meta-analysis

Background: Studies investigating the association between genetic polymorphism of glutathione S-transferase T1 (GSTT1) and risk of colorectal cancer have reported conflicting results. In order to clarify the effect of GSTT1 polymorphism on the risk of developing colorectal cancer, we carried out a meta-analysis using published data to obtain more precise estimates of risk. Methods: Electronic searches of PubMed and EMBASE were conducted to select studies for this meta-analysis. Papers were included if they were observational studies investigating the association between GSTT1 polymorphism and colorectal cancer risk. The principal outcome measure was the odds ratio (OR) with 95% confidence interval (CI) for the risk of colorectal cancer associated with GSTT1 null genotype. Results: We identified 30 eligible studies, which included 7635 cases and 12,911 controls. The combined results based on all studies showed that there was a statistically significant link between GSTT1 null genotype and colorectal cancer risk (OR = 1.20, 95% CI = 1.03–1.40). In the analysis of ethnic groups, we observed distinct differences associated with GSTT1 null genotype, the pooled odds ratios for the GSTT1 polymorphism were 1.32 in Caucasians (95% CI = 1.09–1.58) and 1.03 in Asians (95% CI = 0.81–1.32). As far as concerned the interaction between GSTT1 genotype and colorectal cancer risk in relation to smoking history, there was no increase in risk for smokers or nonsmokers with the GSTT1 null genotype (smokers: OR = 1.13, 95% CI = 0.80–1.60, nonsmokers: OR = 0.99, 95% CI = 0.71–1.38). When stratifying by the location of colorectal cancer, we found that there was a statistically significant link in rectal cancer (OR = 1.50, 95% CI = 1.09–2.07), but not in colon cancer (OR = 1.33, 95% CI = 0.94–1.88). No associations could be detected between null GSTT1 polymorphism and age, sex, tumor stage and differentiation. Conclusion: Our current study demonstrates that GSTT1 null genotype is associated with an increased risk of colorectal cancer, specifically, among Caucasians.     

Lack of association between p53 codon 72 polymorphism and endometrial cancer: a meta-analysis

Background: It has been suggested that the p53 tumor suppressor gene Arg72Pro polymorphism is associated with endometrial cancer. However, results have been inconsistent. We performed this meta-analysis to estimate the association between p53 Arg72Pro polymorphism and endometrial cancer. Methods: An electronic search of PubMed was conducted to select studies. Studies containing available genotype frequencies of Arg72Pro were chosen, and the association was assessed by pooled odds ratios (ORs) with 95% confidence intervals (CIs). Results: Nine published studies, including 829 endometrial cancer cases and 1387 controls, were identified. The overall results suggested that the variant genotypes were not associated with the endometrial cancer risk in all genetic models (additive model: OR 1.027, 95% CI 0.893–1.18, P = 0.71; recessive model: OR 1.099, 95% CI 0.802–1.507, P = 0.556; dominant model: OR 1.013, 95% CI 0.842–1.219 P = 0.89). Similarly, the results were negative in subgroup analyses for ethnicity (Caucasian, Asian). Conclusion: This meta-analysis suggests that p53 codon 72 polymorphism is not associated with increased risk of endometrial cancer, especially in Caucasians and Asians. To validate the association between this polymorphism and endometrial cancer, further studies with larger numbers of participants worldwide are needed.     

An updated meta-analysis on the association of TGF-β1 gene promoter -509C/T polymorphism with colorectal cancer risk

AimPublished data on the association between transforming growth factor-β1 (TGF-β1) gene promoter-509C/T polymorphism and colorectal cancer (CRC) risk are inconsistent and inconclusive. To derive a more precise estimation of this association, a meta-analysis was carried out.MethodsMeta-analysis was performed to evaluate reported studies of the relationship between TGF-β1 gene promoter-509C/T polymorphism and colorectal cancer risk using fixed-effects model and random-effects model.ResultsWe observed an increased colorectal cancer risk among subjects carrying TGF-β1 gene promoter-509CC + CT genotype (odds ratio (OR) = 1.18%, 95% confidence interval (95% CI): 1.06–1.32) using 4440/6785 cases/controls in total population. We observed an increased risk of the TGF-β1 gene promoter -509CC, CT and CC + CT polymorphisms for colorectal cancer in population-based study (OR = 1.36, 95% CI: 1.19–1.56, OR = 1.18, 95% CI: 1.03–1.34 and OR = 1.26, 95% CI: 1.12–1.43, respectively) in stratified analysis. We observed an increased colorectal risk among CC and CC + CT carriers in European and American population (OR = 1.22, 95% CI: 1.04–1.43 and OR = 1.18, 95% CI: 1.02–1.38, respectively). We also observed an increased risk of colon cancer among subjects carrying CC + CT genotype (OR = 1.31, 95% CI: 1.05–1.63).ConclusionsThe present meta-analysis results suggest that TGF-β1 gene promoter -509C allele variant is a possible risk factor for developing colorectal cancer. Recommendations for further studies include pooling of individual data to verify results from the study and to facilitate evaluation of multigenic effects and detailed analysis of effect modification by environmental and lifestyle factors.     

MGMT Ile143Val polymorphism,dietary factors and the risk of breast,colorectal and prostate cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study

O⁶-Methylguanine-DNA methyltransferase (MGMT) repairs DNA damage caused by alkylating agents including N-nitroso compounds from diet. MGMT Ile143Val polymorphism may lead to less DNA damage repair and increased cancer risk depending on the environmental exposures. We investigated interactions between dietary factors and the MGMT Ile143Val polymorphism in relation to breast, colorectal and prostate cancer risk. There were 276/1498, 273/2984 and 312/1486 cases/controls for the breast, colorectal and prostate cancer studies respectively; all nested within the EPIC-Norfolk study, a prospective cohort of approximately 25,000 men and women aged 40–79. Baseline 7-day food diary data were collected for dietary assessment. MGMT Ile143Val polymorphism was not overall associated with breast, colorectal and prostate cancer risk. There was a significant interaction between this polymorphism and intake of red and processed meat on colorectal cancer risk (P_interaction = 0.04) suggesting an increased risk among carriers of the variant genotype compared to the MGMT Ile143Ile common genotype. A lower colorectal cancer risk was seen with higher intake of vitamin E and carotene among the variant genotype group but not in the common genotype group (P_interaction = 0.009 and P_interaction = 0.005 for vitamin E and carotene, respectively). A higher prostate cancer risk was seen with higher alcohol intake among the variant genotype (OR = 2.08, 95% CI = 1.21–3.57, P_interaction = 0.0009) compared to the common genotype with lower alcohol intake. In this UK population, the MGMT Ile143Val polymorphism was not overall associated with breast, colorectal and prostate cancer risk. There was evidence for this polymorphism playing a role in modulating the risk of prostate cancer in presence of alcohol. For colorectal cancer, the MGMT Ile143Val polymorphism may confer increased or decreased risk depending on the dietary exposure.     

Smoking (active and passive), N-acetyltransferase 2, and risk of breast cancer

Background: The relationship between smoking and breast cancer remains controversial. The study aim was to assess the relationship of passive and active smoking to breast cancer risk by N-acetyltransferase 2 (NAT2) phenotype, using a comprehensive assessment of both passive and active smoking. Methods: We undertook a population-based case–control study in Northeastern Ontario, Canada of 347 women diagnosed (2002–2004) with breast cancer and 775 population-based controls. The mailed study package included a questionnaire requesting information about established breast cancer risk factors, passive and active smoking, and a buccal swab for genetic analyses. Results: Among never-active smokers, a long duration of passive smoking was associated with an increased risk of breast cancer (odds ratio (OR) 1.86 (95% confidence interval (95% CI) 1.01–3.44) (test for trend (p = 0.07)); that risk was more elevated for NAT2 slow acetylators (OR 2.76, 95% CI 1.16–6.59) (and highest in extremely slow acetylators), but not elevated for NAT2 fast acetylators (OR 1.17, 95% CI 0.42–3.23). Among active smokers more than 20 pack-years of smoking was associated with an OR of 1.34 (95% CI 0.92-1.96); more elevated among NAT2 fast acetylators OR 1.93 (95% CI 1.01–3.69) but not elevated among NAT2 slow acetylators. Women who were NAT2 fast acetylators in the highest quartile for duration of active smoking had an OR of 2.74 (95% CI 1.42–5.27), with a significant test of trend (p = 0.005). Conclusions: These findings suggest that passive and active smoking may be related to breast cancer, and the effect may be differentially modified by NAT2 phenotype. Further research into the genetic modification of a breast cancer–smoking relationship may help to reconcile earlier discrepant findings.     

Association of TP53 codon 72 and CDH1 genetic polymorphisms with colorectal cancer risk in Bangladeshi population

Till now no pharmacogenetic study of TP53 codon 72 (Arg72Pro) and CDH1 rs16260 (-160C<A) genes has been reported on Bangladeshi population relating those with colorectal cancer. So the aim of the study is to determine whether there is an elevated risk of colorectal cancer development with TP53 codon 72 and CDH1 rs16260 genetic polymorphism in Bangladeshi population for the first time. To investigate the association of these two SNPs, we conducted a case-control study with 288 colorectal cancer patients and 295 healthy volunteers by using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method. We found an increased risk of association between Arg/Pro heterozygosity (adjusted OR = 2.58, 95% CI = 1.77–3.77, p < 0.05) and Pro/Pro mutant homozygosity (adjusted OR = 2.92, 95% CI = 1.78–4.78, p < 0.05) along with the combined genotype (Arg/Pro + Pro/Pro) (adjusted OR = 2.70, 95% CI = 1.90–3.82, p < 0.05) and colorectal cancer predisposition. In case of CDH1 rs16260 polymorphism, C/A heterozygous and A/A mutant homozygous are significantly (p < 0.05) found to be associated with colorectal cancer risk with adjusted OR of 1.94 and 2.63, respectively. The combined genotype of C/A and A/A was also found to be strongly associated with colorectal cancer risk compared to C/C genotype (adjusted OR = 2.02, 95% CI = 1.42–2.87, p < 0.05). In conclusion, heterozygosity and mutant homozygosity as well as the combination of both TP53 Arg72Pro and CDH1 rs16260 polymorphisms are responsible to increase the risk of colorectal cancer development in Bangladeshi population.     

Smoking and alcohol consumption in relation to risk of thyroid cancer in postmenopausal women

Background: Few cohort studies have examined smoking and alcohol consumption in relation to risk of thyroid cancer, and their findings are conflicting. Methods: We therefore assessed the association of smoking and alcohol intake with risk of thyroid cancer in a cohort of 159,340 women enrolled in the Women's Health Initiative. Over 12.7 years of follow-up 331 cases of thyroid cancer, of which 276 were papillary thyroid cancer, were identified. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). Results: Compared to never smokers, ever smokers did not have altered risk. Current smokers had reduced risk for all thyroid cancer (HR 0.54, 95% CI 0.29–1.00) and for papillary thyroid cancer (HR 0.34, 95% CI 0.15–0.78); however, the number of current smokers among cases was small. No associations or trends were seen for amount smoked, age of starting smoking, or age at quitting. Smokers of ≥40 pack-years had a significantly reduced risk of papillary thyroid cancer (HR 0.44, 95% CI 0.21–0.89). In contrast, women who had smoked for < 20 years had increased risk of thyroid cancer (HR 1.35, 95% CI 1.05–1.74) and papillary cancer (HR 1.43, 95% CI 1.09–1.89). Alcohol intake was not associated with risk. Conclusion: Our findings suggest that current smoking and having higher pack-years of exposure are associated with a modestly reduced risk of thyroid cancer, whereas alcohol consumption does not appear to affect risk.     

Diabetes,physical activity and breast cancer among Hispanic women

Purpose: We assessed the association between diabetes and breast cancer and whether physical activity modified the effect of diabetes on breast cancer in Hispanic women. Methods: We used data from a case-control study of breast cancer among Hispanic women aged 30–79 conducted between 2003 and 2008 on the Texas–Mexico border. In-person interviews were completed with 190 incident breast cancer cases ascertained through surgeons and oncologists, and 979 controls who were designated as both high-risk (n = 511) and low-risk (N = 468) for breast cancer (with respective response rates of 97%, 83% and 74%). Results: After adjustment for menopausal status and mammography screening, there was no effect of diabetes on breast cancer risk (high-risk control group odds ratio [OR] 1.02, 95% confidence interval [CI] 0.71–1.48; low-risk control group OR 0.87, 0.58–1.30). Women who had a diabetes history and did not exercise were at no risk of breast cancer (OR 0.96, 95% CI 0.63–1.48) or a slightly reduced breast cancer risk (low-risk control group OR 0.72, 95% CI 0.46–1.15) depending on the control group used, while women with diabetes who did exercise had significantly reduced breast cancer risk (OR 0.41, 95% CI 0.21–0.83) regardless of the control group used (high-risk control group p-value for interaction = 0.013, low-risk control group p-value for interaction 0.183). Conclusions: Should other studies confirm our results, physical activity should be explored as a means of reducing breast cancer risk in diabetic women.     

Polymorphisms in MSH2 gene and risk of gastric cancer, and interactions with lifestyle factors in a Chinese population

Background: Although polymorphisms in DNA mismatch repair (MMR) gene MSH2 have been associated with risks of many cancers, little is known about their etiology role in gastric cancer (GC) and the potential interacting role with lifestyle factors known to damage DNA. Methods: A population-based study was conducted in 3 counties (Jintan, Taixing and Huaian) of Jiangsu Province, the high-risk areas of GC in China. We investigated the association of polymorphisms IVS12?6T>C and IVS10+12G>A in MSH2 gene with the risk of GC and the potential gene–lifestyle interaction. Results: The risk of GC was found to be associated with the IVS12?6C allele (CC vs TT, OR = 2.34, 95% CI: 1.17–4.71) and IVS10+12A allele (GA or AA vs GG, OR = 1.55, 95% CI: 1.14–2.21; and GA vs GG, OR = 1.51, 95% CI: 1.04–2.17). Stratified analysis indicated that an increased risk of GC also was observed in: suspected familial subjects carrying the IVS12?6T>C (OR = 1.68, 95% CI: 1.27–2.66) or IVS10+12G>A (OR = 2.57, 95% CI: 1.53–4.10); or younger subjects carrying the IVS12?6T>C (OR = 2.15, 95% CI: 1.24–3.91) or IVS10+12G>A (OR = 2.23, 95% CI: 1.20–4.33); or male subjects carrying the IVS10+12G>A (OR = 1.64; 95% CI: 1.10–2.54). Furthermore, the combined IVS12?6CC and IVS10+12AA genotypes also significantly increased the risk of GC (OR = 2.12, 95% CI: 1.22–3.66). Statistically significant interactions were observed between: IVS10+12G>A and drinking, high pickled food or fried food intake (OR = 2.32; 95% CI: 1.43–3.78, OR = 2.55; 95% CI: 1.48–4.21 and OR = 2.88; 95% CI: 1.70–4.94, respectively); and IVS12?6T>C and high pickled food intake or fried food intake (OR = 2.65; 95% CI: 1.62–4.47 and OR = 2.48; 95% CI: 1.42–4.13, respectively). Conclusion: The IVS10+12G>A and IVS12?6T>C polymorphisms in MSH2 gene appear to be associated with risk of GC in this Chinese population. Risk for GC, stratified by related genotypes, was further modified by drinking, high pickled food or fried food intake. Larger prospective studies are needed to confirm these findings.     

Cyclin D1 G870A polymorphism is associated with an increased risk of hepatocellular carcinoma in the Turkish population: Case–control study

Background: A common G to A polymorphism (G870A) in the splice donor region of exon 4 of cyclin D1 (CCND1) gene generates two mRNAs (cyclin D1a and D1b) through an alternative splicing at the site of this polymorphism. Cyclin D1a and b proteins differ in their COOH-terminus, a region involved in protein degradation. We examined the association between this CCDN1 genotype and the susceptibility to hepatocellular carcinoma (HCC) in a Turkish population. Methods: The genotype frequency of this polymorphism was determined by using a polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) assay. Hospital-based case–control study was designed consisting of 160 diagnosis subjects with hepatocellular carcinoma and 160 cancer-free control subjects matched on age, gender, smoking and alcohol status. Results: The allele frequencies of case subjects (A, 0.55; G, 0.45) were significantly different from those of control subjects (A, 0.42; G, 0.58) (p = 0.002). The odds ratios (ORs) for the CCND1 870 GA and AA genotypes when compared with the GG genotypes were 1.39 (95% confidence interval [CI] 0.82–2.36, p = 0.22) and 2.52 (95% CI 1.38–4.62, p = 0.003) respectively. The presence of at least one CCND1 870A allele was associated with increased risk for HCC (OR, 1.73; 95% CI, 1.06–2.82, p = 0.03). When combining the GG and GA genotypes as a reference genotype, we found that the OR for the AA genotype was 2.06 (95% CI 1.24–3.44, p = 0.006). Conclusion: Our results suggest that the CCND1 G870A single nucleotide polymorphism is associated with an increased risk of HCC in our Turkish population.     

Polymorphisms in methyl-group metabolism genes and risk of sporadic colorectal cancer with relation to the CpG island methylator phenotype

Background: The CpG island methylator phenotype (CIMP), together with extensive promoter methylation, is regarded as one of the mechanisms involved in colorectal carcinogenesis. The mechanisms underlying CIMP in sporadic colorectal cancer are poorly understood. Genes involved in methyl-group metabolism are likely to affect DNA methylation and thereby influence an individual's risk of CIMP. The aim of the present study was to evaluate whether polymorphisms in the genes encoding methyl-group metabolism pathway predispose to CIMP+ and/or CIMP? CRC. Methods: We examined the potential association between the polymorphisms of MTHFR 677C>T, TS 5′UTR 2R/3R, TS 3′UTR 1494del6, ΔDNMT3B ?149C>T and DNMT3B ?283T>C in a group of 46 CIMP+ CRC cases, 140 CIMP? CRC cases and 140 healthy controls. The CIMP status of the CRC cases was determined by MS-PCR in tumor tissue by a panel of five markers (CACNA1G, IGF2, NEUROG1, RUNX3 and SOCS1), which was also followed by analyzing hMLH1 methylation and BRAF V600E mutation. Results: The variant allele homozygote genotype for the ΔDNMT3B ?283T>C polymorphism was associated with a decreased risk for CIMP+ CRC (OR: 0.31, 95%CI: 0.09–0.73, p = 0.009). Individuals with TS 3R/3R had an increased risk of CIMP? CRC (OR: 2.21, 95%CI: 1.23–4.91, p = 0.01). Moreover, the carriers of 3R allele had an increased risk of CIMP? CRC (OR: 1.45, 95%CI: 1.10–2.13, p = 0.01). Conclusion: This study provides support to the hypothesis that methyl-group metabolism plays a role in the etiology of both CIMP+ and CIMP? colorectal cancers but has a different impact on a distinct molecular subgroups of colorectal cancer.     

Effects of polymorphisms in translesion DNA synthesis genes on lung cancer risk and prognosis in Chinese men

PurposeTranslesion DNA synthesis (TLS) plays an important role in promoting replication through DNA lesions. Genetic polymorphisms in TLS genes may have potential roles in lung cancer development in humans.MethodsWe evaluated the association between genetic variants in six TLS genes and the risk and survival of lung cancer in a case–control study in China. Included in the study are 224 lung cancer patients and 448 healthy controls.ResultsCarriers of the G allele of POLκ rs5744724 had significantly reduced risk of lung cancer (odds ratio (OR) = 0.62, 95% confidence interval (CI): 0.44–0.89), comparing with those carrying the C allele, and the AA genotype of PCNA rs25406 was also associated with significantly decreased cancer risk compared with the major homozygote alleles (OR = 0.47, 95% CI: 0.25–0.86). Haplotype analysis showed that subjects with the POLκ C-G (rs5744533–rs5744724) haplotype had decreased risk of lung cancer (OR = 0.69, 95% CI: 0.49–0.98), comparing with those carrying the C-C haplotype. Besides, the heterozygote of REV1 rs3087386 and rs3792136 were independent prognostic factors for lung cancer survival with hazard radio (HR) 1.54 (95% CI: 1.12–2.12) and 1.44 (95% CI: 1.06–1.97) respectively.ConclusionsOur findings suggested that genetic variants in POLκ and PCNA genes may play roles in the susceptibility of lung cancer, and REV1 gene may have roles in lung cancer survival in Chinese men.     

HapMap-based study identifies risk sub-region on chromosome 19q13.3 in relation to lung cancer among Chinese

Background: Chromosome 19q13.3 has been identified as one of the regions that associate with cancer risk in previous studies. Methods: We systematically examined the 70.772 kb region comprising four genes on chromosome 19q13.3 among Chinese using the haplotype-tagging SNP (htSNP) approach and the HapMap platform. The study involved 339 lung cancer cases and 358 non-cancer controls. Two htSNPs (rs1046282 and rs735482) captured most of the common haplotypes of CD3EA and the combined effects of sixteen htSNPs provided high coverage of common haplotypes of ERCC2, PPP1R13L, CD3EAP and ERCC1. Results: Both carriers of variant CC genotype [adjusted OR (95% CI) = 1.28 (1.02–1.60), P = 0.04] and variant C-allele among >20 years’ smokers [OR (95% CI) = 2.13 (1.24–3.67), P = 0.006] for CD3EAP rs735482 were at increased risk of lung cancer. Four haplotype blocks of strong linkage disequilibrium were identified. The haplotype ERCC2 rs3916874^G and rs238415^C [OR (95% CI) = 1.26 (1.02–1.57), P = 0.03] in block 1 and the haplotype PPP1R13L rs4803817^A, CD3EAP rs1046282^T, rs735482^C, ERCC1 rs3212980^A, rs3212964^G [OR (95% CI) = 3.56 (1.55–8.18), P = 0.005] in block 3 were associated with lung cancer risk. MDR (multifactor dimensionality reduction) analysis demonstrated the best significant model of two-attributes containing smoking duration and rs2298881 in ERCC1 (P = 0.004–0.005) and suggested that the effects of high-order interactions among smoking duration and ERCC2, PPP1R13, ERCC1 htSNPs could modulate lung cancer risk. Conclusions: HapMap-based study of 19q13.3 identified that genetic variation of CD3EAP and two loci were associated with lung cancer risk and interaction of smoking duration and genetic variants was the strongest predictor of lung cancer risk in a Chinese population.     

Childhood passive smoke exposure is associated with adult head and neck cancer

Introduction: Passive smoke is carcinogenic but its association with head and neck squamous cell carcinoma (HNSCC) is uncertain. Methods: We conducted a case-control study of childhood passive smoke exposure (CPSE) and HNSCC in 858 cases and 806 frequency-matched controls using an interviewer-administered questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were estimated with logistic regression controlling for adult smoking in the total study population, and in never-smokers only (184 cases and 415 controls). CPSE was also studied in oropharyngeal separately from other HNSCC using polytomous logistic regression. Results: CPSE was associated with HNSCC (OR, 1.28; 95% CI, 1.01–1.63) after controlling for adult smoking and other factors. This association was similar in magnitude, although not statistically significant, among subjects who never smoked as adults (OR, 1.19, 95% CI, 0.80–1.76). CPSE was associated more strongly with oropharyngeal cancer (a HNSCC subtype commonly associated with human papillomavirus (HPV) infection) than with HNSCC at non-oropharyngeal sites (OR, 2.02; 95% CI, 1.01–4.06, N = 52 cases vs. OR, 1.04; 95% CI, 0.68–1.60, N = 132 cases; P-for-heterogeneity = 0.08). Conclusions: Data from this large US-based case control study suggest a role for CPSE in HNSCC etiology.     

STK15 rs2273535 polymorphism and cancer risk: A meta-analysis of 74,896 subjects

Background: It has been suggested that the serine/threonine kinase 15 (STK15) T91A rs2273535 polymorphism is associated with susceptibility to cancer. However, the results are conflicting. We performed this meta-analysis to derive a more precise estimation of the relationship. Methods: PubMed was searched to select studies. Case–control studies containing available genotype frequencies of the STK15 rs2273535 polymorphism were chosen, and the odds ratio (OR) with its 95% confidence interval (CI) was utilized to assess the strength of association. Results: 52 studies – including 34,057 cases and 40,839 controls – were identified. A significant effect of the STK15 rs2273535 polymorphism on cancer risk was found (AA vs. TT: OR = 1.13, 95%CI = 1.01–1.26, P_{heterogeneity} < 0.001; AA vs. TA/TT: OR = 1.12, 95%CI = 1.02–1.22, P_{heterogeneity} < 0.001; TA/AA vs. TT: OR = 1.06, 95%CI = 1.01–1.12, P_{heterogeneity} < 0.001). Stratified analysis by cancer type revealed that the STK rs2273535 polymorphism may contribute to the risk of breast cancer (AA vs. TT: OR = 1.21, 95%CI = 1.01–1.44, P_{heterogeneity} = 0.002), colorectal cancer (AA vs. TA/TT: OR = 1.24, 95%CI = 1.05–1.47, P_{heterogeneity} = 0.124), and esophageal cancer (AA vs. TA/TT: OR = 1.19, 95%CI = 1.02–1.39, P_{heterogeneity} = 0.148). Further subgroup analysis by ethnicity indicated that there was a statistically increased cancer risk in Asians (AA vs. TA/TT: OR = 1.20, 95%CI = 1.05–1.37, P_{heterogeneity} = 0.004). Conclusion: This meta-analysis suggests that the STK15 rs2273535 polymorphism is a candidate gene polymorphism for cancer susceptibility, especially in Asian populations.     

Examining the association between cigarette smoking and colorectal cancer using historical case–control data

Background: The majority of recent, well-designed studies have shown that long-term cigarette smoking increases colorectal cancer risk, but older studies with shorter durations of exposure often found no association. This study aimed to examine colorectal cancer risk by smoking exposure using data collected in the late-1950s and early-1960s. Methods: This case–control study examined colorectal cancer risk by lifetime smoking history. There were 1365 patients who visited Roswell Park Cancer Institute (RPCI) between 1957 and 1965 diagnosed with primary, incident colorectal cancers that were matched to 4096 malignancy-free controls on gender and age. Odds ratios were calculated using separate logistic regression models for each smoking exposure, while controlling for other tobacco use, county of residence, race, age, gender, and body mass index (BMI). Results: The adjusted OR for individuals who reported their greatest level of smoking to be more than 1 pack/day was 0.87 (95% CI = 0.67–1.15). Among those who smoked 42 or more years, the adjusted OR was 0.89 (95% CI = 0.68–1.15) compared to those who never smoked. For individuals who smoked more than 45 pack-years, the OR was 0.92 (95% CI = 0.72–1.19). The results did not differ significantly by gender, although men had considerably greater exposure compared to women. Results also did not differ by colorectal sub-site. Conclusion: No association was found between long-term cigarette smoking and colorectal cancer risk. These results are in accord with studies that followed cohorts throughout the 1950s and 1960s. Methodological limitations, such as missing data on covariates and the higher incidence of smoking-related illness in a hospital setting, may have contributed to the null results found in this study. Prolonged population exposure to cigarettes and perhaps a changing product may explain why more recent studies have reported a positive association between smoking and colorectal cancer.     

No association between garlic intake and risk of colorectal cancer

BackgroundAlthough experimental studies suggested beneficial role of garlic intake on colorectal carcinogenesis, limited prospective cohort studies have evaluated garlic intake in relation to colorectal cancer (CRC) incidence.MethodsWe followed 76,208 women in the Nurses’ Health Study and 45,592 men in the Health Professionals Follow-up Study for up to 24 years and examined garlic intake and garlic supplement use in relation to CRC risk. Information on garlic intake and supplement use was assessed using a validated food frequency questionnaire and a Cox proportional hazard regression model was used to estimate the multivariable hazard ratio (MV-HR) and 95% confidence intervals (95% CIs).ResultsWe documented 2368 (1339 women and 1029 men) incident CRC cases and found no association between garlic intake and CRC risk; the MV-HRs (95% CIs) associated with garlic (1 clove or 4 shakes per serving) intake ≥1/day compared with <1/month were 1.21 (0.94–1.57; p-trend = 0.14) for women and 1.00 (0.71–1.42; p-trend = 0.89) for men. The MV-HRs (95% CIs) of CRC for garlic supplement use, which was used in 6% of the participants in each study, were 0.72 (0.48–1.07) for women and 1.22 (0.83–1.78) for men.ConclusionOur prospective data do not support an important role of garlic intake or garlic supplement use in colorectal carcinogenesis.     

Factors associated with inadequate colorectal cancer screening with flexible sigmoidoscopy

Background and study aim: Inadequate colorectal cancer screening wastes limited endoscopic resources. We examined patients factors associated with inadequate flexible sigmoidoscopy (FSG) screening at baseline screening and repeat screening 3–5 years later in 10 geographically-dispersed screening centers participating in the ongoing Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Methods: A total of 64,554 participants (aged 55–74) completed baseline questionnaires and underwent FSG at baseline. Of these, 39,385 participants returned for repeat screening. We used logistic regression models to assess factors that are associated with inadequate FSG (defined as a study in which the depth of insertion of FSG was <50 cm or visual inspection was limited to <90% of the mucosal surface but without detection of a polyp or mass). Results: Of 7084 (11%) participants with inadequate FSG at baseline, 6496 (91.7%) had <50 cm depth of insertion (75.3% due to patient discomfort) and 500 (7.1%) participants had adequate depth of insertion but suboptimal bowel preparation. Compared to 55–59 year age group, advancing age in 5-year increments (odds ratios (OR) from 1.08 to 1.51) and female sex (OR = 2.40; 95% confidence interval (CI): 2.27–2.54) were associated with inadequate FSG. Obesity (BMI >30 kg/m²) was associated with reduced odds (OR = 0.67; 95% CI: 0.62–0.72). Inadequate FSG screening at baseline was associated with inadequate FSG at repeat screening (OR = 6.24; 95% CI: 5.78–6.75). Conclusions: Sedation should be considered for patients with inadequate FSG or an alternative colorectal cancer screening method should be recommended.     

G-308A TNF-α polymorphism is associated with an increased risk of hepatocellular carcinoma in the Turkish population: Case-control study

Background: Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine that may act as an endogenous tumor promoter. A genetic polymorphism of TNF-α gene at position ?308 promoter region is involved in the regulation of expression level and has been found to be associated with susceptibility to various types of cancer. Methods: To determine the association of the TNF-α gene G-308A polymorphism on the risk of hepatocellular carcinoma (HCC) in a Turkish population, a hospital-based case-control study was designed consisting of 110 diagnosis subjects with hepatocellular carcinoma and 110 cancer-free control subjects matched on age, gender, smoking and alcohol status. The genotype frequency of this polymorphism was determined by using a polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) assay. Results: The distribution G-308A genotype was significantly associated with the risk of HCC (p < 0.001, odds ratio [OR] = 4.75, 95% confidence interval [CI] = 2.25–9.82 for ?308 AA/GA genotypes versus GG genotype). Conclusion: We suggested that the presence of the high producer allele ?308A in the TNF-α gene appears to be associated with an increased risk for the development of HCC in Turkish population.     

Community-acquired infections and their association with myeloid malignancies

Introduction: Antigenic stimulation is a proposed aetiologic mechanism for many haematological malignancies. Limited evidence suggests that community-acquired infections may increase the risk of acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS). However, associations with other myeloid malignancies including chronic myeloid leukaemia (CML) and myeloproliferative neoplasms (MPNs) are unknown. Materials and methods: Using the Surveillance, Epidemiology and End Result (SEER)-Medicare database, fourteen community-acquired infections were compared between myeloid malignancy patients [AML (n = 8489), CML (n = 3626) diagnosed 1992–2005; MDS (n = 3072) and MPNs (n = 2001) diagnosed 2001–2005; and controls (200,000 for AML/CML and 97,681 for MDS/MPN]. Odds ratios (ORs) and 95% confidence intervals were adjusted for gender, age and year of selection excluding infections diagnosed in the 13-month period prior to selection to reduce reverse causality. Results: Risk of AML and MDS respectively, were significantly associated with respiratory tract infections, bronchitis (ORs 1.20 [95% CI: 1.14–1.26], 1.25 [95% CI: 1.16–1.36]), influenza (ORs 1.16 [95% CI: 1.07–1.25], 1.29 [95% CI: 1.16–1.44]), pharyngitis (ORs 1.13 [95% CI: 1.06–1.21], 1.22 [95% CI: 1.11–1.35]), pneumonia (ORs 1.28 [95% CI: 1.21–1.36], 1.52 [95% CI: 1.40–1.66]), sinusitis (ORs 1.23 [95% CI: 1.16–1.30], 1.25 [95% CI: 1.15–1.36]) as was cystitis (ORs 1.13 [95% CI: 1.07–1.18], 1.26 [95% CI: 1.17–1.36]). Cellulitis (OR 1.51 [95% CI: 1.39–1.64]), herpes zoster (OR 1.31 [95% CI: 1.14–1.50]) and gastroenteritis (OR 1.38 [95% CI: 1.17–1.64]) were more common in MDS patients than controls. For CML, associations were limited to bronchitis (OR 1.21 [95% CI: 1.12–1.31]), pneumonia (OR 1.49 [95% CI: 1.37–1.62]), sinusitis (OR 1.19 [95% CI: 1.09–1.29]) and cellulitis (OR 1.43 [95% CI: 1.32–1.55]) following Bonferroni correction. Only cellulitis (OR 1.34 [95% CI: 1.21–1.49]) remained significant in MPN patients. Many infections remained elevated when more than 6 years of preceding claims data were excluded. Discussion: Common community-acquired infections may be important in the malignant transformation of the myeloid lineage. Differences in the aetiology of classic MPNs and other myeloid malignancies require further exploration.