Breast Cancer In Mexican Women Research Articles

Polymorphisms of the XRCC1 gene and breast cancer risk in the Mexican population.

The purpose of this case-control study was to evaluate the association of XRCC1 Arg194Trp and Arg399Gln polymorphisms with susceptibility to breast cancer (BC) in a Mexican population. We analysed DNA samples from 345 BC patients and 352 control subjects by polymerase chain reaction-restriction fragment length polymorphism. The frequency of the 399Gln allele was 23% in controls and 29% in patients [OR 1.38 (1.08-1.76); p = 0.01]; genotypes in controls were 60, 36, and 4% for Arg/Arg, Arg/Gln, and Gln/Gln, respectively, while in patients they were 53, 36, and 11% [OR 2.71 (1.44-5.10); p = 0.0015 for the Gln/Gln genotype]. Regarding the Arg194Trp polymorphism, the frequency of Trp allele was 15% in controls and 16% in patients [OR 1.09 (0.82-1.46); p = 0.54]; the genotype frequencies in controls were 74, 23, and 3% for Arg/Arg, Arg/Trp and Trp/Trp, respectively, while in patients these were 73, 23, and 4% [OR 1.41 (0.64-3.14); p = 0.39 for the Trp/Trp genotype]. Allele frequencies were consistent with Hardy-Weinberg equilibrium (p = 0.20 for Arg194Trp and p = 0.54 for Arg399Gln). Our results indicate that the 399Gln polymorphism is associated with an increased risk of BC. Additionally, we found that some covariates increase the risk of BC in Mexican women; namely, antecedent of abortions [OR 3.69 (2.17-6.27); p < 0.001], not breastfeeding [OR 2.46 (1.45-4.18); p = 0.001], family history of BC [OR 15.9 (5.09-50.23); p < 0.001], other type of family cancer [OR 31.5 (12.5-79.3); p < 0.001], alcoholism [OR 17.7 (5.2-60.42); p < 0.001], type 2 diabetes mellitus [OR 2.28 (1.26-4.10); p = 0.007], and contraceptive use [OR 2.28 (1.26-4.10); p < 0.001].

Prediabetes, Diabetes, and Risk of Breast Cancer: A Case-Control Study

Although underlying mechanisms have been described to account for the association between prediabetes and diabetes with breast cancer, reported results have been inconsistent. We undertook this study to determine whether prediabetes and diabetes are risk factors for breast cancer in Mexican women with no family history of breast cancer in the mother, daughters, or sisters. A case-control study was carried out during 2011-2013. "Case" referred to patients with a histopathological diagnosis of breast cancer (incident and primary cases) (n = 240); "controls" were those with a BI-RADS 1 or 2 mammography result (n = 406). Categorization of prediabetes and diabetes was based on self-reporting or fasting glucose and glycated hemoglobin blood sampling results. Reproductive and sociodemographic data were collected by interview. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated using multivariate unconditional binary logistic regression analysis. Prediabetes increased the risk of breast cancer in postmenopausal women (adjusted OR 2.08, 95% CI 1.10-3.96) as did diabetes (adjusted OR 2.85, 95% CI 1.55-5.26). A history of diabetes preceding breast cancer by ≥7 years and <7 years were both associated with an increased risk for breast cancer (adjusted OR 2.80, 95% CI 1.40-5.60 and 3.00, 95% CI 1.50-5.90, respectively). This is the first study in Mexico evaluating prediabetes and diabetes as breast cancer risk factors in women with no first-degree relatives with breast cancer. Our findings suggest that women with prediabetes and diabetes should be considered a more vulnerable population for early breast cancer detection.

Anthropometry, silhouette trajectory, and risk of breast cancer in Mexican women.

Obesity has been associated with breast cancer risk in the Caucasian population but the association remains unclear in the Hispanics. Previous studies conducted among Hispanics in the U.S. have shown inconsistent results. The association between anthropometry, body shape evolution across lifetime, and the risk of breast cancer was assessed using a multi-center population-based case-control study conducted in Mexico. One thousand incident cases and 1074 matched control women aged 35-69 years were recruited between 2004 and 2007, and analyzed in 2011-2012. Conditional logistic regression models were used. Height was related to an increased risk of breast cancer in both premenopausal (p trend=0.03) and postmenopausal women (p trend=0.002). In premenopausal women, increase in BMI; waist circumference (WC); hip circumference (HC); and waist-hip ratio (WHR) were inversely associated with breast cancer risk (p trends<0.001 for BMI and WC, 0.003 for HC, and 0.016 for WHR). In postmenopausal women, decreased risks were observed for increased WC (p trend=0.004) and HC (p trend=0.009) among women with time since menopause <10 years. Further analysis of body shape evolution throughout life showed strong and significant increase in risk of breast cancer among women with increasing silhouettes size over time compared to women with no or limited increase. These findings suggest that anthropometric factors may have different associations with breast cancer risk in Hispanic women than in Caucasian women. This study also shows the importance of considering the evolution of body shape throughout life.

Hormonal Therapy and Risk of Breast Cancer in Mexican Women

The use of hormonal therapies, including hormonal contraceptives (HC) and postmenopausal hormone replacement therapy (HRT) have been shown to influence breast cancer (BC) risk. However, the variations of these effects among populations and ethnic groups are not completely documented, especially among Hispanic women. We evaluated the association between HC and premenopausal BC risk, and between HRT and postmenopausal BC risk in Mexican women. Data from a Mexican multi-center population-based case–control study ofwomen aged 35 to 69 years were analysed. A total of 1000 cases and 1074 matched controls were recruited between 2004 and 2007. Information on hormonal therapy was collected through a structured questionnaire. Results were analysed using conditional logistic regression models. Overall, HC were used by 422/891 (47.3%) premenopausal women and HRT was used by 220/1117 (19.7%) postmenopausal women. For HC, odds ratios (ORs) for BC were 1.11 (95% confidence interval (CI): 0.82, 1.49) for current users and 1.68 (95% CI: 0.67, 4.21) for ever-users. No clear effect of duration of use was observed. For HRT, the OR for BC was significantly increased in ever users (OR: 1.45; 95% CI: 1.01, 2.08). A non-significant increased risk was observed for combined estrogen/progestin, (OR = 1.85; 95% CI: 0.84, 4.07) whereas no effect was observed for the use of estrogen alone (OR = 1.14; 95% CI: 0.68, 1.91). Our results indicate that, HC had a non-significant effect on the risk of pre-menopausal BC, but suggested that injected contraceptives may slightly increase the risk, whereas HRT had a significant effect on post-menopausal BC in this population. This study provides new information about the effects of HC and HRT on BC risk in a Mexican population, which may be of relevance for the population of Latin America as a whole.

No association between Epstein-Barr Virus and Mouse Mammary Tumor Virus with breast cancer in Mexican women.

Breast cancer is the most frequent malignancy affecting women worldwide. It has been suggested that infection by Epstein Barr Virus (EBV), Mouse Mammary Tumor Virus or a similar virus, MMTV-like virus (MMTV-LV), play a role in the etiology of the disease. However, studies looking at the presence of these viruses in breast cancer have produced conflicting results, and this possible association remains controversial. Here, we used polymerase chain reaction assay to screen specific sequences of EBV and MMTV-LV in 86 tumor and 65 adjacent tissues from Mexican women with breast cancer. Neither tumor samples nor adjacent tissue were positive for either virus in a first round PCR and only 4 tumor samples were EBV positive by a more sensitive nested PCR. Considering the study's statistical power, these results do not support the involvement of EBV and MMTV-LV in the etiology of breast cancer.

Association Between rs2981582 Polymorphism in the FGFR2 Gene and the Risk of Breast Cancer in Mexican Women

The rs2981582 single nucleotide polymorphism in the fibroblast growth factor receptor 2 gene has been consistently associated with an increased risk of breast cancer. We evaluated the effect of rs2981582 polymorphism in the FGFR2 gene on the risk of breast cancer and its interaction with non-genetic risk factors. A population-based case-control study was conducted in Mexico. Data from 687 cases and 907 controls were analyzed. The T allele of the rs2981582 polymorphism was associated with an increased risk of breast cancer (ORper allele= 1.24, 95% CI 1.06-1.46). There was also an interaction between this polymorphism and alcohol consumption (p= 0.043). The effect of alcohol consumption on the risk of breast cancer varied according to the allelic variants of the rs2981582 polymorphism in the FGFR2 gene: OR= 3.97 (95% CI 2.10-7.49), OR= 2.01 (95% CI 1.23-3.29) and OR= 1.21 (95% CI 0.48-3.05) for genotypes CC, CT and TT, respectively. This is the first study exploring the association between rs2981582 polymorphism in the FGFR2 gene and breast cancer risk in Mexican women. The interaction found may be of great public health interest because alcohol consumption is a modifiable breast cancer risk factor. Therefore, replication of this finding is of foremost importance.

Association of the tumor necrosis factor-alpha -308G&gt;A polymorphism with breast cancer in Mexican women

The tumor necrosis factor-alpha (TNF-α) gene plays an important role in cell proliferation, differentiation, apoptosis, lipid metabolism, coagulation, insulin resistance, and endothelial function. Polymorphisms of TNF-α have been associated with cancer. We examined the role of the -308G>A polymorphism in this gene by comparing the genotypes of 294 healthy Mexican women with those of 465 Mexican women with breast cancer. The observed genotype frequencies for controls and breast cancer patients were 1 and 14% for AA, 13 and 21% for GA, and 86 and 65% for GG, respectively. We found that the odds ratio (OR) for AA genotype was 2.4, with a 95% confidence interval (95%CI) of 5.9-101.1 (P = 0.0001). The association was also evident when comparing the distribution of the AA-GA genotype in patients in the following categories: 1) premenopause and obesity I (OR = 3.5, 95%CI = 1.3-9.3, P = 0.008), 2) Her-2 neu and tumor stage I-II (OR = 2.5, 95%CI = 1.31-4.8, P = 0.004), 3) premenopause and tumor stage III-IV (OR = 1.7, 95%CI = 1.0-2.9, P = 0.034), 4) chemotherapy non-response and abnormal hematocrit (OR = 2.4, 95%CI = 1.2-4.8, P = 0.015), 5) body mass index and Her-2 neu and III-IV tumor stage (OR = 2.8, 95%CI = 1.2- 6.6, P = 0.016), and 6) nodule metastasis and K-I67 (OR = 4.0, 95%CI = 1.01-15.7, P = 0.038). We concluded that the genotypes AA-GA of the -308G>A polymorphism in TNF-α significantly contribute to breast cancer susceptibility in the analyzed sample from the Mexican population.

Intron 4 VNTR (4a/b) Polymorphism of the Endothelial Nitric Oxide Synthase Gene Is Associated with Breast Cancer in Mexican Women

The endothelial nitric oxide synthase (eNOS) gene plays an important role in several biological functions. Polymorphisms of the eNOS gene have been associated with cancer. It has been suggested that the VNTR 4 a/b polymorphism may affect the expression of eNOS and contributes to tumor promotion in the mammary gland. We examined the role of the eNOS4 a/b polymorphism by comparing the genotypes of 281 healthy Mexican women with the genotypes of 429 Mexican women with breast cancer (BC). The observed genotype frequencies for control and BC patients were 0.6% and 0.7% for a/a (polymorphic); 87% and 77% for a/a (wild type); and 12% and 22% for a/b respectively. We found that the odds ratio (OR) was 1.9, with a 95% confidence interval (95%CI) of 1.29-2.95, P = 0.001 for genotypes a/a-a/b, b/c. The association was also evident when comparing the distribution of the a/a-a/b genotypes in patients with high levels of glutamate-oxaloacetate transaminase (SGOT) (OR, 1.93; 95% CI, 1.14-3.28; P = 0.015); undergoing menopause with high levels of SGOT (OR, 2.0; 95% CI, 1.1-3.84); and with high levels of glutamic-pyruvic transaminase (SGPT) (OR, 3.5; 95% CI, 1.56-8.22). The genotypes a/a-a/b are associated with BC susceptibility in the analyzed samples from the Mexican population.

CYP2W1, CYP4F11 and CYP8A1 Polymorphisms and Interaction of CYP2W1 Genotypes with Risk Factors in Mexican Women with Breast Cancer

Breast cancer (BCa) is the leading type of cancer in Mexican women. Genetic factors, such as single nucleotide polymorphisms (SNP) of P450 system, have been reported in BCa. In this report, and for the first time in the literature, we analyzed the rs3735684 (7021 G>A), rs11553651 (15016 G>T) and rs56195291 (60020 C>G) polymorphisms in the CYP2W1, 4F11 and 8A1 genes in patients with BCa and in healthy Mexican women to identify a potential association between these polymorphisms and BCa risk. Patients and controls were used for polymorphism analysis using an allelic discrimination assay with TaqMan probes and confirmed by DNA sequencing. Links with clinic-pathological characteristics were also analyzed. Statistical analysis was performed using the standard χ2 or Fisher exact test statistic. No significant differences were observed in the distributions of CYP2W1 (OR 8.6, 95%CI 0.43-172.5 P>0.05; OR 2.0, 95%CI 0.76-5.4, P>0.05) and CYP4F11 (OR 0.3, 95%CI 0.01-8.4 P>0.05) genotypes between the patients and controls. Only the CYP8A1 CC genotype was detected in patients with BCa and the controls. All polymorphism frequencies were in Hardy-Weinberg Equilibrium (HWE) in the controls (P>0.05). We found a significant association between BCa risk and smoking, use of oral contraceptives or hormonal replacement therapy (HRT), obesity, hyperglycemia, chronic diseases, family history of cancer and menopausal status in the population studied (P<0.05). Tobacco, oral contraceptive or HRT, chronic diseases and obesity or overweight were strongly associated with almost eight, thirty-five, nine and five-fold increased risk for BCa. Tobaco, obesity and hyperglycemia significantly increased the risk of BCa in the patients carrying variant genotypes of CYP2W1 (P<0.05). These results indicate that the CYP2W1 rs3735684, CYP4F11 rs11553651 and CYP8A1 rs56195291 SNPs are not a key risk factor for BCa in Mexican women. This study did not detect an association between the CYP2W1, 4F11 and 8A1 genes polymorphisms and BCa risk in a Mexican population. However, some clinico-pathological risk factors interact with CYP2W1 genotypes and modifies susceptibility to BCa.

ω-3 and ω-6 Polyunsaturated Fatty Acid Intakes and the Risk of Breast Cancer in Mexican Women: Impact of Obesity Status

ω-3 polyunsaturated fatty acids (PUFA) could play a protective role on the risk of breast cancer; however, little is known about this relation among Mexican women. We evaluated the association between ω-3 and ω-6 PUFA intake and breast cancer risk by obesity status in Mexican women. A population-based case-control study was conducted in Mexico, including 1,000 incident breast cancer cases and 1,074 controls matched to cases by age, health care system, and region. Women provided information on health and diet by in-person interview. Body mass index (BMI) measures were used to define overall obesity. Obesity status was categorized as normal weight (18.5 < BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30). A conditional logistic regression model was used to assess the association between PUFA and breast cancer risk. Overall, there was no significant association between ω-3 PUFA intake and breast cancer risk (P = 0.31). An increased risk of breast cancer was associated with increasing ω-6 PUFA intake in premenopausal women [OR = 1.92, 95% confidence interval (CI) = 1.13-3.26; P = 0.04]. A decreased risk of breast cancer was significantly associated with increasing ω-3 PUFA intake in obese women (OR = 0.58, 95% CI = 0.39-0.87; P = 0.008) but not in normal weight nor in overweight women (P(heterogeneity) = 0.017). Obesity status may affect the association between ω-3 PUFA intake and breast cancer risk. The underlying mechanisms may be related to decreased inflammation and improved adipokin and estrogen levels induced by ω-3 PUFA in adipose tissue in obese women. Increased intake of ω-3 PUFA should be recommended among Mexican women in particular in obese women.

Abstract P6-09-05: Insulin Resistance, Diabetes Mellitus and Breast Cancer Risk in Pre-and Postmenopausal Women: Modification Effect by Moderate Physical Activity

Abstract Background It has been hypothesized that diabetes may influence the risk of breast cancer (BC) by impaired regulation of the insulin and insulin-like growth factors (IGF) pathways. Current evidence supports a reduction in BC risk by doing regular physical activity due, in part, by reducing insulin resistance and improving glucose control. Material and Methods A population based case control study was conducted to evaluate the association between insulin resistance and diabetes mellitus on the risk of BC in Mexican women. A total of 1000 incident cases and 1074 matched controls to cases by five years of age, site and health institution were analyzed. Women provided information on health, diet and physical activity by means of a face to face interview; information about the family history of diabetes mellitus and whether or not women were diagnosed with this disease. Anthropometric measurements and blood samples were obtained from all women. A conditional logistic regression model was used to assess this association. Results In postmenopausal women, there was an interaction between physical activity and diabetes mellitus on the risk of BC. The effect of diabetes mellitus type 2 decreased with increasing moderate physical activity (OR = 3.67, 95% CI 1.78 — 7.58; OR = 2.86, 95% CI 1.37 — 5.96; OR = 0.82, 95% CI 0.19 — 3.59, by increasing tertiles of daily hours of moderate physical activity respectively); in premenopausal women, this association was not statistically significant (OR = 1.55, 95% CI 0.86-2.79), however in a subsample of premenopausal women, an increase was observed in the risk of BC per unit change in the increase of C-peptide, an indirect marker of insulin resistance (OR = 1.98, 95% CI 1.41 - 2.76). Discussion The results of this study are consistent with numerous mechanisms linking physical activity directly to reduce BC risk probably, in part, through reducing insulin resistance and improving glucose control. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-09-05.

Global DNA methylation and risk of breast cancer in Mexican women

Global DNA methylation and risk of breast cancer in Mexican women

Alcohol and risk of breast cancer in Mexican women

Little is known about the relationship between alcohol intake and breast cancer risk among Mexican women. This association may be modified by folate and Vitamin B12. A population-based case-control study conducted in Mexico recruited 1,000 incident breast cancer cases aged 35-69 and 1,074 controls matched on age, region, and health care system. In-person interviews were conducted to assess breast cancer risk factors and recent diet using a food frequency questionnaire. Conditional logistic regression models estimated adjusted odds ratios and 95% confidence intervals. Over one-half (57%) of cases and less than one-half of controls (45%) reported any lifetime alcohol consumption. Compared with never drinkers, women reporting ever drinking (Adjusted OR = 1.25, 95% CI = 0.99-1.58) had a greater odds of breast cancer. There was evidence for interaction in the association between ever consuming any alcohol and breast cancer by folate (p for interaction = 0.04) suggesting women with lower folate intake had a higher odds of breast cancer (Adjusted OR = 1.99, 95% CI = 1.26-3.16) compared to women with higher folate intake (OR = 1.12, 95% CI = 0.69-1.83). Our findings support evidence that any alcohol intake increases risk of breast cancer. Insufficient intake of folate may further elevate risk for developing breast cancer among women who consume alcohol.

Prevalence of Methylenetetrahydrofolate Reductase C677T and A1298C Polymorphisms and Risk of Breast Cancer in Mexican Women: An Interim Report of a Case-Control Study.

Abstract Background: Among other causes, Breast Cancer (BC) appears as a result of genetic and epigenetic changes. Modifications in important pathways, such as the reactions that provide essential cofactors for synthesis of S-adenosylmethionine (one-carbon metabolism), and those involved in DNA synthesis and methylation could be linked to the development of this disease. Research has been conducted about whether MTHFR polymorphisms are related to the development of breast cancer in at least 10 different races, with different outcomes. Two of the most frequently studied MTHFR polymorphisms are C677T and A1298C, and their frequency is unknown among Mexican women. Our objective was to determine the frequency of these two polymorphisms and to ascertain weather their presence increases the risk of developing BC in our population.Materials and methods: 37 blood samples from histopatologically confirmed breast cancer patients were collected from hospitals in Monterrey, Uruapan and Villahermosa, all in Mexico. 115 healthy control samples were obtained from the same cities, and were matched for age in 5-year interval-groups. Cases and controls were third generation Mexican and older than 18 years. Genotyping of every sample was performed by PCR and restriction with enzymes.Results: The C677T Polymorphism was found in 28 cases (75.67%), whereas 76/115 controls (66.08%) showed the polymorphic allele. Case-controls analysis was adjusted to the confounding variable age group, an odds ratio of 1.58 (IC 95% de 0.66 – 3.82) was obtained. We did not find a significant relationship between the presence of the C677T polymorphism and the presence of breast cancer. The A1298C Polymorphism was found in 19/37 cases (51.35%), while only 32/115 (27.82%) of the control samples contained the allele. The odds ratio adjusted for the same confounding variable was 2.72 (IC 95%: 1.26 – 5.87). These results suggest a significant association between the presence of the polymorphism and BC.Discussion: Despite the exhaustive research that has been conducted regarding MTHFR polymorphisms C677T and A1298C, their association to the risk of breast cancer remains unclear. Some research groups even suggest that the presence of the polymorphisms, either individually or combined, confers certain protection against the disease. Up until now there were no data in Mexican population. Differences in the results of different works probably lie in the nature of the populations analyzed and the experimental design. We believe that a bigger sample size will allow us to determine if A1298C polymorphism is indeed, a risk factor for BC in Mexican women. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3064.

The role of obesity, physical activityand dietary factors on the risk for breast cancer: mexican experience

We provide an overview of the role of adiposity, physical activity and diet in the risk for breast cancer in Mexican women. Lack of physical activity, diets high in carbohydrates and in glycemic load and low intake of folate and vitamin B12 have been shown to increase the risk of breast cancer in Mexican women, in particular postmenopausal breast cancer. Other dietary factors that may begin to play a more relevant role in breast cancer incidence in Mexico are alcohol intake and vitamin D status. Recommendations to maintain a healthy weight, practice moderate physical activity, decrease intake of rapidly absorbed carbohydrates and increase consumption of fruits and vegetables could have an important impact on the epidemic of breast cancer in Mexico.

Steroid metabolism gene CYP17, CYP1A1*2B, CYP1A1*2C and risk of breast cancer in mexican women

Steroid metabolism gene CYP17, CYP1A1*2B, CYP1A1*2C and risk of breast cancer in mexican women

Steroid metabolism gene CYP17, CYP1A1*2B, CYP1A1*2C and risk of breast cancer in Mexican women

1524 Background: Breast cancer is the 2nd cause of women mortality in Mexico, increasing this rate over the past ten years. Functional polymorphisms in genes encoding steroid metabolizing enzymes may contribute to this understanding by serving as surrogate markers for altered long-term hormone exposure and, thus, as biomarkers of individual breast cancer susceptibility. In order to determine the impact of CYP17 and CYP1A1 genotypes on the risk to develop breast cancer, we realized a case-control study of breast cancer patients and healthy controls among women invited to participate in this study from a Public Hospital in Mexico City. Methods: 90 breast cancer patients and 87 healthy controls, who had given their informed consent were included. All breast cancer patiens had pathologically confirmed as breast carcinoma, all were diagnosed and treated at the “1o de Octubre” hospital. Epidemiological questionnaire and genotyping data were obtained. CYP17 and CYP1A1 were genotyped using PCR/restriction fragment lenght polymorphism. For CYP17 a single nucleotide polymorphism at the 5‘untraslated region of the CYP 17 was done (MspA1 restriction sitie). Two polymorphism for CYP1A1 were analized: 2455 A>G (CYP1A1*2B) and 4889 A >G (CYP1A1 *2C). Results: We found an increased risk of breast cancer in women carrying the allele CYP1A1*2B. The odds ratio was 2.6 (CI95%= 1.08–6.4; p <0.032). In the stratified analysis, this risk was increased when CYP1A1*2B and CYP1A1*2C were presented together. The odds ratio was 3.4 (CI95%= 1.2- 9.3; p<0.017). Regarding the CYP17 genotype, it was not preliminary associated with breast cancer risk. Conclusions: These results suggest that CYP1A1*2B and CYP1A1*2C genotype could be a biomarker for breast cancer risk in our general Mexican population. It‘s necesary to increase the sample size and add others genes encoding steroid metabolizing enzymes. No significant financial relationships to disclose.

Factores pronósticos relacionados con la supervivencia del cáncer de mama

To evaluate prognostic factors for breast cancer in Mexican women. Four hundred and thirty two women with breast cancer, admitted from 1990 to 1999 to the General Hospital of Mexico, were included to evaluate their survival using the Kaplan-Meier technique and Cox proportional hazard method. Overall 5-year survival was 58.9%. The shortest survival rate corresponds to the clinical stage (IIIB, 47.5%; IIIA, 44.2%; and IV, 15%), the haematological metastasis (21.4%) and surgical edges with positive tumor (12.5%). Lymph node-positive (RR, 1.9; IC95%, 1.3-2.8), clinical stage IV (RR, 14.8; IC95%, 5.5-39.7) and surgical edges with positive tumor (RR, 2.4; IC95%, 1.2-4.8) were the central prognostic factors. These results give consistency to diagnostic and therapeutic criteria for women with breast cancer who receive medical attention in Mexico, taking into consideration the characteristics of the tumor -such as extension, clinical stage and status of the lymph nodes- before making a decision as to the initial therapy.

Genetic expression profiles and chromosomal alterations in sporadic breast cancer in Mexican women

Breast cancer is the second-leading cause of death among Mexican women >35 years of age. At the molecular level, changes in many genetic pathways have been reported to be associated with this neoplasm. To analyze these changes, we determined gene expression profiles and chromosomal structural alterations in tumors from Mexican women. We obtained mRNA to identify expression profiles with microarray technology, and DNA to determine amplifications and deletions, in 10 fresh sporadic breast tumor biopsies without treatment, as well as in 10 nonaffected breast tissues. Expression profiles were compared with genetic changes observed by comparative genomic hybridization (CGH). We compared the expression profiles against the structural alterations from the studied genes by means of microarrays; at least 17 of these genes correlated with DNA copy number alterations. We found that the following genes were overexpressed: LAMC1, PCTK3, CCNC, CCND1, FGF3, PCTK2, L1CAM, BGN, and PLXNB3 (alias PLEXR). Underexpressed genes included CASP9, FGR, TP73, HSPG2, and ERCC1; genes turned off included FRAP1, EPHA2 (previously ECK), IL12A, E2F5, TNFRSF10B, TNFRSF10A, EFNB3, and BCL2. The results will allow us, in the near future, to outline genes that could serve as diagnostic, prognostic, or target therapy markers for the Mexican population.

Glycemic Load, Glycemic Index, and the Risk of Breast Cancer Among Mexican Women

The amount and composition of dietary carbohydrates is a major determinant of postprandial blood glucose and insulin, and risk of breast cancer has been positively associated with plasma levels of insulin and insulin-like growth factor 1. We sought to evaluate dietary glycemic load (GL) and overall glycemic index (GI) in relation to breast cancer risk in Mexican women. We examined dietary GL and overall GI and breast cancer risk among 475 women with histologically-confirmed breast cancer and a random sample of 1391 women from Mexico City households. Diet was assessed using a food frequency questionnaire adapted to the Mexican population. The multivariate adjusted or for all women comparing the highest quartile of dietary GL with the lowest quartile was 1.62 (95% CI 1.13-2.32; p-test for trend = 0.02) with a significant trend. In postmenopausal women, the multivariate adjusted or comparing the extreme quartiles was 2.18 (95% CI 1.34-3.55; p-test for trend=0.005). Overall GI was not significantly associated with risk of breast cancer. High intake of rapidly absorbed carbohydrate appears to play an important role in the risk of breast cancer in Mexican women.