Breast Cancer Risk From Modifiable and Non-Modifiable Risk Factors among Women in Southeast Asia: A Meta-Analysis

Objective: The aim of this study was to determine breast cancer risk from modifiable and non-modifiable factors among women in Southeast Asia. Methods: This meta-analysis was performed on research articles on breast cancer risk factors in PubMed, ProQuest and EBSCO databases published between 1997 and October 2017. Pooled odds ratios (OR) are calculated using fixed and random-effect models. Data were processed using Review Manager 5.3 (RevMan 5.3). Results: From a total of 1,211 articles, 15 studies (1 cohort and 14 case control studies) met the criteria for systematic review. Meta-analysis results showed that of the known modifiable risk factors for breast cancer, parity (nulipara) had the highest odd ratio (OR = 1.85 [95% CI 1.47-2.32]) followed by body mass index (overweight) (OR = 1.61 [95% CI 1.43-1.80]) and use of oral contraceptives (OR = 1.27 [95% CI 1.07-1.51]). Of non-modifiable risk factors, family history of breast cancer had the highest odd ratio (OR = 2.53 [95% CI 1.25-5.09]), followed by age (≥ 40 years) (OR = 1.53 [95% CI 1.34-1.76]) and menopausal status (OR = 1.44 [95% CI 1.26-1.65]). Conclusion: This analysis confirmed associations between both modifiable risk factors (parity, body mass index and use of oral contraceptives) and non-modifiable risk factors (family history of breast cancer, age and menopausal status) with breast cancer.     

Risk factors of breast cancer in north of Iran: a case-control in Mazandaran Province.

INTRODUCTION: Breast cancer is the most common cancer among Iranian women. This study aimed to determine risk factors for breast cancer in the north of Iran. METHOD: A matched case-control study was conducted in Mazandaran province of Iran in 2004 of 250 biopsy proven cases of breast cancer and 500 neighbor controls that were matched by age within a 3 year period. Statistical analysis was carried out using conditional logistic regression with the backward elimination method and crude and adjusted odds ratios with related 95% CIs were estimated with Stata 8.0 software RESULTS: Multivariate analysis showed that higher education (OR=4.70, 95%CI: 1.71-12.88), late menopause (OR=4.18, 95%CI: 2.54-6.88), history of induced abortion (OR=1.62, 95%CI: 1.13-2.31), positive first-degree family history of breast cancer (OR=3.14, 95%CI: 1.37-7.20), and BMI (OR=1.02, 95%CI: 1.01-1.03) were risk factors for breast cancer. Furthermore, having more episodes of full term pregnancy (OR=0.87, 95%CI: 0.80-0.95), longer duration of breast feeding (OR=0.993, 95%CI: 0.989-0.997) and parity more than 2 were shown to be protective factors. CONCLUSIONS: Our study revealed the role of some modifiable determinants of breast cancer that can be focused by public health intervention in the northern community of Iran. Accordingly, the women who have one or more of the following risk factors should take the special attention to risk of breast cancer: obesity, being menopause, positive family history of breast cancer and history of induced abortion. The protective effect of longer duration of breast feeding should be encouraged too.     

No Association of the TGF-β1 29T/C Polymorphism with Breast Cancer Risk in Caucasian and Asian Populations: Evidence from a Meta-Analysis Involving 55, 841 Subjects

The transforming growth factor-β1 (TGF-β1) gene 29 T/C polymorphism is thought to be associated withbreast cancer risk. However, reports are largely conflicting and underpowered. We therefore conducted a metaanalysisof all available case-control studies relating the TGF-β1 29T/C polymorphism to the risk of developingbreast cancer by including a total of 31 articles involving 24,021 cases and 31,820 controls. Pooled ORs weregenerated for the allele contrasts, with additive genetic, dominant genetic and recessive genetic models. Subgroupanalysis was also performed by ethnicity for the TGF-β1 29T/C polymorphism. No association was found in theoverall analysis (C vs T: OR=1.028, 95% CI=0.949-1.114, p-value 0.500; CC vs TC: OR= 1.022, 95% CI=0.963-1.085, p-value 0.478; CC vs TT: OR= 1.054, 95% CI=0.898-1.236, p-value 0.522; CC vs TT+ TC: OR= 1.031, 95%CI=0.946-1.124, p-value 0.482; TT vs CC+TC: OR= 0.945, 95% CI=0.827-1.080, p-value 0.403). Similarly, in thesubgroup analysis by ethnicity, no association was found in Caucasian (C vs T: OR= 1.041, 95% CI=0.932-1.162,p-value 0.475; CC vs TC: OR= 1.031, 95% CI=0.951-1.118, p-value 0.464; CC vs TT: OR= 1.081, 95% CI=0.865-1.351, p-value 0.493; CC vs TT+TC: OR= 1.047, 95% CI=0.929-1.180, p-value 0.453; TT vs CC+TC: OR= 0.929,95% CI=0.775-1.114, p-value 0.429;) and Asian populations (C vs T: OR= 1.004, 95% CI=0.908-1.111, p-value0.931; CC vs TC: OR= 0.991, 95% CI=0.896-1.097, p-value 0.865; CC vs TT: OR= 1.015, 95% CI=0.848-1.214,p-value 0.871; CC vs TT+TC: OR= 1.000, 95% CI=0.909-1.101, p-value 0.994; TT vs CC+TC: OR= 0.967, 95%CI=0.808-1.159, p-value 0.720;). No evidence of publication bias was detected during the analysis. No significantassociation with breast cancer risk was demonstrated overall or on subgroup (Caucasian and Asian) analysis.It can be concluded that TGF-β1 29T/C polymorphism does not play a role in breast cancer susceptibility inoverall or ethnicity-specific manner.     

Genetic Polymorphisms of Xenobiotic Metabolizing Genes (GSTM1, GSTT1, GSTP1), Gene-Gene Interaction with Association to Lung Cancer Risk in North India; A Case Control Study

Aim: In this case control study involving, 220 human subjects; polymorphisms in xenobiotic metabolizing genes (GST-M1, -T1 and -P1) and their association to lung cancer risk is being analysed among smokers and non-smokers. GSTM1 or GSTT1 gene polymorphism and amino acid changes in GSTP1 have been correlated and may be associated to lung cancer risk. Other factor includes exposure to environmental pollutants and life style choices. We have explored gene-gene and gene-environment interaction in the aetiology of lung cancer risk among north Indian population. Patients and Methods: For the study we have collected 120 lung cancer patient blood samples from Kamala Nehru Memorial Cancer Hospital, Allahabad, Uttar Pradesh and 100 matched controls. DNA was isolated and GST-M1 and - T1 genotyping were assessed by multiplex PCR whereas the GSTP1 polymorphism was analysed using restriction fragment length polymorphism. The risk of lung carcinogenesis was assessed using logistic regression analysis calculating the odd ratio (OR) with 95% confidence interval (CI). Results: The risk of lung carcinogenesis was three fold higher for null GSTT1 (OR=3.045, 95%CI=1.750-5.301, p-value <0.001) genotype; whereas other two types; GSTM1 (OR= 1.342, 95% CI=0.788-2.284, p-value=0.270) and GSTP1 (OR=0.806, 95% CI=0.526-1.236, p-value=0.323) showed no association to lung cancer susceptibility respectively. Smokers diagnosed with lung cancer had more null genotypes for GSTT1 (OR=4.773, 95%CI=1.939-11.751, p<0.001). The ‘at risk’ genotype combination GSTM1 (null) /GSTT1 (null) (OR=1.76, 95%CI; 0.920-3.370, p-value=0.03) showed increased susceptibility to lung cancer risk. The genotype combination of GSTT1 (null)/GSTP1 (Ile/Ile) (p=0.009) was associated with increased lung cancer risk. Conclusion: The results of this study suggest that; GSTT1 null genotype were more susceptible for lung cancer risk and smoking increases the susceptibility for lung cancer several folds among the North Indian population. Gene-gene interaction for null genotypes of GSTM1 and GSTT1 were correlated with higher risk of having lung cancer.     

Systemic Analysis on Risk Factors for Breast Cancer Related Lymphedema

Background: To evaluate risk factors for upper extremity lymphedema due to breast cancer surgery. Materials and Methods: Clinical studies published on PubMed, Ovid, EMbase, and Cochrane Library from January 1996 to December 2012 were selected. Results: Twenty-five studies were identified, including 12,104 patients. Six risk factors related to the incidence of lymphedema after breast cancer treatment were detected: axillary lymph node dissection (OR=3.73, 95%CI 1.16 to 11.96), postoperative complications (OR=2.64, 95%CI 1.10 to 6.30), hypertension (OR=1.83, 95%CI 1.38 to 2.42), high body mass index (OR=1.80, 95%CI 1.30 to 2.49), chemotherapy (OR=1.38, 95%CI 1.07 to 1.79) and radiotherapy (OR=1.35, 95%CI 1.10 to 1.66). We found significant protective factors for lymphedema: pathologic T classification (OR=0.57, 95%CI 0.36 to 0.91) andstage (OR=0.60, 95%CI 0.39 to 0.93), while some factors, like age, number of positive lymph nodes, number of lymph node dissection, demonstrated no obvious correlation. Conclusions: Axillary lymph node dissection, postoperative complications, hypertension, body mass index, chemotherapy, radiotherapy are risk factors for lymphedema after breast cancer treatment. Attention should be paid to patients with risk factors to prevent the occurrence of lymphedema.     

Awareness of Breast Cancer among Female Care Givers in Tertiary Cancer Hospital,China

Objective: Breast cancer is a worldwide public health issue and most common cancer diagnosed among women including China, where advanced stages at diagnosis appears to be increasing and an ever-rising incidence twice as fast as global rates. The study was conducted to describe the awareness of breast cancer and associated factors among care giver women in tertiary Cancer Hospital, China. Methods: Institutional based cross-sectional study was conducted among 261 women selected by systematic random sampling. Information provided by the participants was converted into awareness scores for analysis using SPSS version 23. Awareness scores were dichotomized in to ‘good awareness and ‘poor awareness’ taking median score=11 as the cut-off point. Data analysis was performed using the binary logistic regression. A p-value of Result: The study showed that 46.7% of the respondents had good awareness. Breast lump was the most commonly known symptom of cancer by 61.7% of the respondents. Slightly more than half of the study participants acknowledged having a past history of breast cancer, drinking alcohol and having close relative with breast cancer as potential risk factors for breast cancer (63.6%, 58.6%, and 55.6% respectively). Nevertheless, a vast majority of the study participants were unable to appreciate modifiable risk factors of the disease. More than half of the participants had never/rarely checked their breasts and all of the participants wrongly answered breast cancer knowledge age related risk. Awareness level was significantly associated with entertainment preference (OR=3.57; 95%CI=1.71, 7.44) and residence setting areas (OR=2.4; 95%CI=1.04, 5.69). Conclusion: The study indicated suboptimal awareness while entertainment preference and residence setting were significantly associated with awareness level. Public awareness campaigns should be made by dissemination of information about breast cancer through health education and printed Medias with great emphases on women living in rural areas.     

ABO Blood Groups and Risk of Cancer: a Systematic Review and Meta-analysis

Background: For decades, studies have been performed to evaluate the association between ABO bloodgroups and risk of cancer. However, whether ABO blood groups are associated with overall cancer risk remainsunclear. We therefore conducted a meta-analysis of observational studies to assess this association. Materialsand Methods: A search of Pubmed, Embase, ScienceDirect, Wiley, and Web of Knowledge databases (to May2013) was supplemented by manual searches of bibliographies of key retrieved articles and relevant reviews.We included case-control studies and cohort studies with more than 100 cancer cases. Results: The searchyielded 89 eligible studies that reported 100,554 cases at 30 cancer sites. For overall cancer risk, the pooled ORwas 1.12 (95%CI: 1.09-1.16) for A vs. non- A groups, and 0.84 (95%CI: 0.80-0.88) for O vs. non-O groups. Forindividual cancer sites, blood group A was found to confer increased risk of gastric cancer (OR=1.18; 95%CI:1.13-1.24), pancreatic cancer (OR=1.23; 95%CI: 1.15-1.32), breast cancer (OR=1.12; 95%CI: 1.01-1.24), ovariancancer (OR=1.16; 95%CI: 1.04-1.27), and nasopharyngeal cancer (OR=1.17; 95%CI: 1.00-1.33). Blood groupO was found to be linked to decreased risk of gastric cancer (OR=0.84; 95%CI: 0.80-0.88), pancreatic cancer(OR=0.75; 95%CI: 0.70-0.80), breast cancer (OR=0.90; 95%CI: 0.85-0.95), colorectal cancer (OR=0.89; 95%CI:0.81-0.96), ovarian cancer (OR=0.76; 95%CI: 0.53-1.00), esophagus cancer (OR=0.94; 95%CI: 0.89-1.00), andnasopharyngeal cancer (OR=0.81; 95%CI: 0.70-0.91). Conclusions: Blood group A is associated with increasedrisk of cancer, and blood group O is associated with decreased risk of cancer.     

Determinants of Breast Cancer Screening Practice among Women in Indonesia: A Nationwide Study

Background: Breast cancer remains the leading cause of death for women globally, including in Indonesia. Breast cancer screening plays a vital role in reducing deaths caused by breast cancer. However, breast cancer screening rate is still low and studies on determinants for breast cancer screening is limited in Indonesia. This study aimed to identify the determinants of breast cancer screening among women in Indonesia. Methods: This population-based study was conducted among 827 women who lived in either rural and urban areas, using a stratified sampling design where were based on province and locality combinations. Data were analysed using a binary logistic regression model to assess the associations between independent and dependent variables. Results: As many as 827 women with an average age of 29.91 (± 11.14) years old participated in this study. The overall breast cancer screening among women was 18.74%. Knowledge of breast cancer risk factors, signs, and symptoms (adj.OR = 1.75, 95%CI: 1.20 – 2.56), age of 35 to 39 years old (adj.OR. = 1.52, 95% CI: 1.02 – 2.26), and household income of ≥6,000,000 IDR (≥457 USD) (adj.OR. = 5.19, 95%CI: 1.43–18.84) were associated with breast cancer screening attendance. In contrast, Christian women had a significantly lower breast cancer screening rate that women from other religions (adj. OR. = 0.45, 95%CI: 0.24 – 0.85). Conclusion: The overall breast cancer screening attendance was poor among Indonesian women population. Age, household income, religion, and knowledge of breast cancer risk factors were identified as the determinant factors for breast cancer screening.     

Risk Factors,Patterns, and Distribution of Bone Metastases and Skeletal-Related Events in High-Risk Breast Cancer Patients

Background: More than a quarter of breast cancer patients are at risk to develop recurrent metastases to the bone. Objective: This study was designed to identify risk factors and predilections of bone metastasis and skeletal-related events (SRE) in a population of breast cancer survivors initially diagnosed in advanced stages and with high-risks of relapse. Methods: Associated risk factors, distribution, and attainable treatment of bone metastasis and SRE were analyzed in a cohort of 1,329 breast cancer patients. The association with dependent variables was subsequently analyzed using multivariable logistic regression. Sociodemographic and adverse clinical characteristics were included as covariates of progression into bone metastasis and SREs. Results: Of 1329 breast cancer patients, 246 patients (18.5%) were diagnosed as metastatic breast cancer in which 232 of them (94.3%) had bone metastases. Spines were the most common sites of bone metastases (25.6%). In multivariable analysis, advanced stage at diagnosis (OR=1.840, 95%CI:1.198-2.826, P=0.005), luminal subtype (OR=1.788, 95%CI:1.206-2.652, P=0.045), lobular histology (OR=1.795, 95%CI:1.012-3/184, P=0.046), positive axillary lymph node (OR=1.771, 95%CI:1.087-2.886, P=0.022), multiple metabolic comorbidities (OR=2.193, 95%CI:1.371-3.508, P=0.001), early menopause (OR=2.136, 95%CI:1.116-4.464, P=0.046) were significantly associated with risk of recurrent bone metastases. SREs occurred in 89 (68.5%) patients. Several risk factors for SREs were early menopausal age (OR=2.342, P=0.024), advanced stages (OR=1.404, P=0.039), lobular histology (OR=2.279, P=0.007), and having multiple metabolic comorbidities (OR=1.728, P=0.039). Conclusion: Bone metastases and SREs are relatively high in breast cancer patients diagnosed in advanced stages. Luminal subtypes, having multiple metabolic comorbidities, and lobular histology are associated with higher risks of recurrent bone metastases. Living in rural areas and advanced stage at diagnosis as a risk factors for bone metastases might represent a social gradient of care delivery.     

MiR-34b/c rs4938723 Polymorphism Significantly Decreases the Risk of Digestive Tract Cancer: Meta-analysis

Background: Previous studies investigating the association between miR-34b/c rs4938723 polymorphism andcancer risk showed inconclusive. Here, we performed meta-analysis to investigate the association between miR-34b/c rs4938723 polymorphism and digestive cancer risk. Materials and Methods: Literature database includingPubMed, OVID, Chinese National Knowledge Infrastructure (CNKI) were searched for publications concerningthe association between the miR-34b/c rs4938723 polymorphism and digestive cancer risk. Results: A total of 6studies consisting of 3246 cases and 3568 controls were included in this meta-analysis. The combined analysissuggested the miR-34b/c rs4938723 polymorphism significantly reduced digestive cancer risk under allelic model,homogeneous co-dominant model and recessive model (C vs T: OR=0.88, 95%CI=0.82-0.95, p-value=0.001; CCvs TT: OR =0.67, 95%CI=0.57-0.80, p-value=0.000; CC vs TT/TC: OR=0.68, 95%CI=0.58-0.80, p-value=0.000).Q-test and I2 test revealed no significant heterogeneity in all genotype comparisons. The Begger’s funnel plot andEgger’s test did not show significant publication bias. Conclusions: The current evidence supports the conclusionthat the miR-34b/c rs4938723 polymorphism decreases an individual’s susceptibility to digestive cancers.     

Risk Factors for Breast Cancer in Iranian Women Aged Less than 40 Years

This case-control study was carried out in a university-affiliated teaching hospital, Tehran city, Iran. A total of312 newly diagnosed cases aged less than 40 years old participated and were matched for age and ethnicity with312 controls. The results showed that in women who never married (OR=2.42 95%CI=1.51-3.88) (P<0.001), hada family history of breast cancer (OR=7.07 95%CI=2.95-16.99) (P<0.001), a low age of menarche (OR=0.1 95%CI=0.04-0.23) (P<0.001)), lower parity (OR=13.3 95% CI=3.89-45.66) (P<0.001) and took oral contraceptive pills(OR= 2.83 95% CI=1.87-4.24) (P<0.000) were at increased risk. A direct association with age at first birth wasalso evident(P=0.041), with a significantly inverse association between duration of lactation and breast cancer risk(p=0.016). On multivariate logistic regression, parity, family history of breast cancer, use of oral contraceptivepills, and age at first birth remained significant. In women lower than 40 years of age, breast cancer risk wassignificantly higher in women with parity ≥4 compared with nulliparity but no association emerged with historyof breast-feeding. Other risk factors were similar to those described in breast cancer epidemiology at any age.     

Cigarette Smoking and Breast Cancer: a Case-control Study in Serbia

Background: Despite the fact that breast cancer is the most common female cancer worldwide, more than halfof the breast cancer risk factors remained unexplained. The aim of this study was to investigate the associationof cigarette smoking with risk of breast cancer. Materials and Methods: A case-control study was conductedin the Clinical Centre of Kragujevac, Serbia, covering 382 participants (191 cases and 191 controls). In theanalysis of data logistic regression was used. Results: Breast cancer risk was significantly increased in thosewho quit smoking at ≤50 years of age (OR=2.72; 95% confidence interval - 95%CI=1.02-7.27) and in those whoquit smoking less than 5 years before diagnosis of the disease (OR=4.36; 95%CI=1.12-16.88). When smokerswere compared with nonsmokers without passive exposure to smoking, former smoking significantly increasedbreast cancer risk (OR=2.37; 95%CI=1.07-5.24). Risk for breast cancer was significantly increased in those whoquit smoking at ≤50 years of age (OR=3.29; 95%CI=1.17-9.27) and in those who quit smoking less than 5 yearsbefore diagnosis of the disease (OR=5.46; 95%CI=1.34-22.28). Conclusions: These data suggest that cigarettesmoking is associated with an elevated risk of breast cancer among former smokers in Serbia.     

The MTHFR C677T polymorphism and prostate cancer risk: new findings from a meta-analysis of 7306 cases and 8062 controls

Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme involved in folate metabolism; a single nucleotide polymorphism (SNP) C677T has been reported to be linked with altered incidences of several diseases. We here conducted a meta-analysis of 15 published epidemiological studies with a total of 7306 cases and 8062 controls to evaluate its association with prostate cancer risk with overall and subgroup analyses. No statistical relationship was found overall with any genetic model (TT vs. CC: OR = 0.80, 95%CI = [0.62, 1.04], P = 0.094; CT vs. CC: OR = 0.97, 95%CI = [0.84; 1.12], P = 0.667; Dominant: OR = 0.94, 95%CI = [0.82; 1.07], P = 0.343; Recessive: OR = 0.81, 95%CI = [0.64; 1.04], P = 0.104), but after the exclusion of several studies, we could observe the homozygote TT to confer less susceptibility to prostate cancer in carriers; moreover, different effects of the polymorphism on prostate cancer risk was detected from subgroup analysis stratified by participants' residential region: significant reduced prostate cancer risk was found to be associated with the polymorphism from Asian studies (TT vs. CC: OR = 0.47, 95%CI = [0.33; 0.67], P< 0.001; CT vs. CC: OR = 0.73, 95%CI = [0.60; 0.90], P = 0.002; Dominant: OR = 0.67, 95%CI = [0.56; 0.82], P< 0.001; Recessive: OR = 0.55, 95%CI = [0.40; 0.76], P< 0.001) while studies from Europe indicated a slight increased risk under dominant model with marginal significance (OR = 1.14, 95%CI = [0.99; 1.30], P = 0.064). Moreover, the protective effect of the polymorphism against prostate cancer was also shown by studies performed in yellow Asians (TT vs. CC: OR = 0.48, 95%CI = [0.31; 0.75], P = 0.001; CT vs. CC: OR = 0.68, 95%CI = [0.51; 0.90], P = 0.006; Dominant: OR = 0.63, 95%CI = [0.48; 0.82], P < 0.001; Recessive: OR = 0.57, 95%CI = [0.39; 0.84], P = 0.004). We propose that these phenomena should be viewed with the consideration of folate metabolism profile and different gene background as well as living habits of different populations, and more relevant studies should be conducted to confirm our hypothesis and provide a comprehensive and clear picture concerning this topic.     

Breast Cancer Risk From Modifiable and Non-Modifiable Risk Factors among Palestinian Women: A Systematic Review and Meta-Analysis

Objective: Breast cancer (BC) is known as one of the deadliest forms of cancer, and it is increasing globally. Identifying risk factors for BC is a key point in developing preventive strategies to reduce its occurrence. Herein, we aimed to conduct a systematic review and meta-analysis focus on the risk factors for BC in Palestine. Material and Methods: We performed a systematic search via PubMed, MEDLINE, SCOPUS, Science Direct, Cochrane library, Emerald Insight, and Google scholar for identifying studies published on BC risk factors up to March 2021. Pooled odds ratios (OR) are calculated using fixed and random-effect models. Data were processed using Review Manager 5.4 (RevMan 5.4). Results: From a total of 73 articles, seven case-control studies met the criteria for systematic review. Meta-analysis results showed that of the known modifiable risk factors for BC, diabetes mellitus (DM) had the highest odds ratio (OR = 4.97, 95% CI 3.00- 8.25) followed by hypertension (OR = 3.21, 95% CI 1.96-5.23), obesity (BMI >30 Kg/m2) (OR = 2.90, 95% CI 2.00- 4.21), and passive smoking (OR = 1.50, 95% CI 1.12- 2.02). Controversially, breastfeeding (OR = 0.37, 95% CI 0.23- 0.61) was protective factor in BC. Of non-modifiable risk factors for BC has reached menopause had the highest odds ratio (OR = 3.74, 95% CI 2.64- 5.29), followed by family history of BC (OR = 2.63, 95% CI 1.07-6.44) and age (≥ 40 years) (OR = 2.49, 95% CI 1.43-4.34). Conclusions: The most significant predictors of BC in Palestine were DM, hypertension, passive smokers, age (>40), reached menopause, and family history of BC. Almost all these risk factors are consistent with known risk factors for breast cancer in other parts of the world.     

A Nested Case-Control Study of Female Breast Cancer in Karunagappally Cohort in Kerala,India

Lifestyle factors related to breast cancer risk were examined in a case-control study nested in a cohort inKarunagappally, Kerala, South India. We sought interviews with all the residents in Karunagappally with thepopulation of 385,103 (191,149 males and 193,954 females) in the 1991 census and established a cohort of 359,619(93% of the population in 1991) in 1990. For analysis 264 breast cancer cases with age ≥20 years were selectedfrom 438 breast cancer cases reported during the period 1990-2004 and for each case 3 non-cancer controlswere randomly selected matched for age, religion and place of residence through the Cancer Registry,Karunagappally. Conditional logistic regression was used for the analysis. In the present study, in addition to alow number of pregnancies (P <0.001 and P for trend <0.001), more frequent intake of roots and tubers excepttapioca (cassava) (OR for ≥ 5 times =1.56, 95% CI=1.09, 3.09, P for trend <0.05), milk drinking (OR=1.78, 95%CI=1.17-2.69, P<0.01) and consumption of chicken meat (OR=1.84, 95%CI=1.09-3.09, P<0.05) were found toincrease breast cancer risk. The present study further showed that consumption of tapioca which is a commonlyused food item in South India, particularly in Kerala, reduced breast cancer risk (OR=0.55, 95%CI=0.37-0.83,P<0.01). Risk analysis was attempted among pre- and post-menopausal women separately and similar oddsratio were obtained. Consumption of tapioca (cassava) decreased risk of developing breast cancer among premenopausalwomen (P<0.001 and OR=0.35, 95%CI=0.18, 0.65) and a low number of pregnancies (P<0.01),consumption of roots & tubers (P<0.05), usage of chicken meat (P=0.05) increased the risk of breast canceramong post-menopausal women. Further studies seem warranted to confirm the possible protective effect oftapioca consumption. There is an increasing need of breast cancer prevention programs responsive to the culturalpractices of the people and the study results should provide leads to cancer control programs especially in ruralareas.     

No Association Between MTHFR A1298C Gene Polymorphism and Head and Neck Cancer Risk: A Meta-analysis Based on 9,952 Subjects

Objective: Findings for associations between the methylenetetrahydrofolate reductase (MTHFR) A1298C genepolymorphism and head and neck cancer risk have been conflicting. We therefore performed a meta-analysisto derive a more precise relationship. Methods: Ten published case-control studies were collected and oddsratios (ORs) with 95% confidence intervals (CIs) were used to assess the association between MTHFR A1298Cpolymorphism and head and neck cancer risk. Sensitivity analysis and publication bias assessment also wereperformed to guarantee the statistical power. Results: Overall, no significant association between MTHFR A1298Cpolymorphism and head and neck cancer risk was found in this meta-analysis (C vs. A: OR=1.04, 95%CI=0.87-1.25, P=0.668, Pheterogeneity<0.001; CC vs. AA: OR=1.07, 95%CI=0.70-1.65, P=0.748, Pheterogeneity<0.001; ACvs. AA: OR=1.06, 95%CI=0.88-1.27, P=0.565, Pheterogeneity<0.001; CC+AC vs. AA: OR=1.06, 95%CI=0.86-1.30,P=0.571, Pheterogeneity<0.001; CC vs. AA+AC: OR=1.02, 95%CI=0.69-1.52, P=0.910, Pheterogeneity<0.001). Similarresults were also been found in succeeding analysis of HWE and stratified analysis of ethnicity. Conclusions: Inconclusion, our meta-analysis demonstrates that MTHFR A1298C polymorphism may not be a risk factor fordeveloping head and neck cancer.     

中国女性乳腺癌危险因素的Meta分析

[目的]评价中国女性乳腺癌部分危险因素的作用,探讨乳腺癌的病因。[方法]运用Meta分析方法对我国1996～2006年间公开发表的有关乳腺癌危险因素病例对照研究的12篇文献资料进行定量综合分析。[结果]各因素合并OR值分别为：初潮年龄OR=1．5401（95％CI：1．3437～1．7654）;哺乳OR=0．6837（95％CI：0．4779—0．9782）;口服避孕药OR=1．3278（95％CI：1．0627—1．6589）;良性乳腺疾病史OR=2．6180（95％CI：2．0275—3．3804）;吸烟OR=1．8576（95％CI：1．5394—2．2415）;饮酒OR=0．8137（95％CI：0．6196～1．0686）;饮茶OR=0．8625（95％CI：0．7646～0．9728）。[结论]初潮年龄、口服避孕药、良性乳腺疾病史及吸烟是乳腺癌发生的危险因素,哺乳及饮茶则是乳腺癌的保护因素。     

Oral Contraceptives,Abortion and Breast Cancer Risk: a Case Control Study in Saudi Arabia

Background: Several studies have examined the relationship between oral contraceptive pill (OCP) use,abortions and breast cancer, with mixed results. Hormonal changes associated with OCP use and abortion mayincrease risk of breast cancer over time, but there is a lack of studies studying this association in Saudi Arabianwomen. Materials and Methods: We thererfore conducted a case control study in 192 women (92 as cases and 100as controls), aged 30 to 65, and collected information on variables including examples related to study objectivesand those which may confound findings. The Chi square test was used to detect associations between variousfactors and risk of breast cancer. Results: We found no evidence of interaction between history of abortion orfrequency of abortion and breast cancer risk (Chi square=0.422, p =0.420 and 1, p =0.169) respectively. Oralcontraceptives did not confer risk for breast cancer overall (OR=0.276, 95%CI 0.092-0.829, p=0.524), while longterm use of OCP was associated with increased risk of breast cancer (OR=0.297, 95%CI 0.158-0.557, p=0.001),with higher association for those who used 10 years or more of OCPs (OR=0.282, 95%CI 0.095-0.835, p=0.02).Age at first use of OCPs had no effect on breast cancer risk (p=0.452) or age at diagnosis (p=0.074). Conclusions:Prolonged use of OC (more than 10 years) may be associated with increased risk of breast cancer in Saudi women.Larger population based studies are needed to confirm this finding in this population.     

2q35 rs13387042和8q24 rs13281615单核苷酸多态性与中国东北汉族绝经前妇女乳腺癌风险关系

背景与目的：乳腺癌作为中国女性最常见的恶性肿瘤,每年的新发数量和死亡数量分别占全世界的12.2%和9.6%,但与中国乳腺癌患者明显相关的基因多态位点至今尚不清楚。本研究旨在探讨2q35 rs13387042和8q24 rs13281615单核苷酸多态性与中国北方汉族绝经前妇女乳腺癌风险关系,为预防和治疗乳腺癌提供循证依据。方法：采用多重单碱基延伸单核苷酸多态性分型技术(SNaPshot)分析方法,检测了280例绝经前乳腺癌患者和287例绝经前正常对照者2q35 rs13387042和8q24 rs13281615多态性位点基因型,并比较不同基因型和等位基因与乳腺癌风险的关系。结果：2q35 rs13387042多态性位点基因型频率在乳腺癌和对照样本之间差异有统计学意义(P=0.017);8q24 rs13281615多态性位点基因型频率在乳腺癌和对照样本之间差异无统计学意义(P=0.967)。Logistic回归分析结果显示,对于2q35 rs13387042位点,与GG相比,GA和GA+AA基因型携带者显著增加乳腺癌的患病风险(OR=1.793,95%CI：1.177～2.733,P=0.007;OR=1.691,95%CI：1.122～2.550,P=0.012),而AA携带者与乳腺癌的患病风险无关(OR=0.572,95%CI：0.104～3.153,P=0.521);与G等位基因相比,A等位基因显著增加乳腺癌的患病风险(OR=1.505,95%CI：1.033～2.193,P=0.033)。对于8q24rs13281615位点,与AA相比,AG、GG和AG+GG基因型携带者与乳腺癌的患病风险无关(OR=0.992,95%CI：0.660～1.490,P=0.968;OR=1.047,95%CI：0.642～1.708,P=0.853;OR=1.007,95%CI：0.682～1.487,P=0.971);与A等位基因相比,G等位基因不增加乳腺癌患病风险(OR=1.021,95%CI：0.809～1.288,P=0.863)。结论：本实验证实2q35 rs13387042多态性位点能够增加中国北方汉族绝经前妇女乳腺癌易感风险,而8q24 rs13281615多态性位点与中国北方汉族绝经前妇女乳腺癌易感性无明显相关性。     

Association Between Three eNOS Polymorphisms and Cancer Risk: a Meta-analysis

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene may influence the risk of cancer, but the results are still debatable. Therefore, we performed a systematic review to provide a more complete picture and conducted a meta-analysis to derive a precise estimation. We searched PubMed, EMBASE, EBSCO, Google Scholar and China National Knowledge Infrastructure (CNKI) databases until April 2014 to identify eligible studies. Thirty-one studies with cancer patients and controls were included in the meta-analysis. Overall, thepolled analysis revealed that the T-786C polymorphism was significantly associated with increased cancer risk under multiple genetic models (C vs T: OR=1.135, 95%CI=1.048-1.228; CC vs TT: OR=1.278, 95%CI=1.045-1.562; TC vsTT: OR=1.136, 95%CI=1.023-1.261; CC+TC vs TT: OR=1.159, 95%CI=1.047-1.281; CC vs TC+TT: OR=1.204, 95%CI= 1.003-1.447). G894T was associated with significant risk for females (TT vs GG: OR=1.414, 95%CI=1.056-1.892; TT vs GT+GG: OR=1.356, 95%CI=1.108-1.661) and for breast cancer (T vs G: OR=1.097, 95%CI=1.001-1.203; TT vs GG: OR=1.346, 95%CI=1.012-1.789; TT vs GT+GG: OR=1.269, 95%CI=1.028-1.566). Increased susceptibility was revealed for prostate cancer with 4a/b (ba vs bb: OR=1.338, 95%CI=1.013-1.768; aa+ba vs bb: OR=1.474, 95%CI=1.002-2.170). This meta-analysis indicated that the eNOS T-786C polymorphism is associated with elevated cancer risk; the G894T polymorphism contributes to susceptibility to breast cancer and cancer generally in females; and the 4a/b polymorphism may be associated with prostate cancer risk.