Apolipoprotein E genetic polymorphism, serum lipoproteins, and breast cancer risk

The Relationship between Cancer and Dementia: An Updated Review

The risk of cancer and dementia increases with age, raising complex questions about whether it is appropriate to continue cancer treatment in older patients. There is emerging research suggesting the association between cancer and dementia. However, the mechanistic underpinnings are still under investigation. Progress has already been made toward understanding the cognitive effects associated with cancer therapy. Such associations raise awareness about the need to establish better prevention methods and early screening in clinical practice. Additionally, recent studies have suggested possible therapeutic strategies for better preserving cognitive function and reducing the risk for dementia before patients start cancer treatment. We review the current literature and summarize the incidence and mechanisms of cognitive impairment in patients with lung cancer, breast cancer, head and neck cancer, gastric cancer, prostate cancer, colorectal cancer, and brain tumor/brain metastasis following different kinds of therapies. Possible risk factors are suggested to identify the early onset of cognitive changes in cancer patients and provide more insight into the pathophysiological process of dementia.

Effects of APOE gene ε4 allele on serum lipid profiles and risk of cardiovascular disease and tumorigenesis in southern Chinese population

Background

Human apolipoprotein E (APOE) polymorphisms are attributable to the presence of three common alleles, namely, ε2, ε3, and ε4, which generate six genotypes, viz, E2/E2, E2/E3, E3/E3, E3/E4, E4/E4, and E2/E4. APOE polymorphisms are associated with all types of tumors and cardiovascular diseases (CVD). However, the relationship between the type of APOE polymorphisms and tumorigenesis remains debatable. Therefore, we aimed to investigate the role of APOE polymorphisms on the tumor with or without CVD in southern China.

Methods

A total of 1438 participants were categorized into 4 groups: 409 patients with tumor, 369 patients with CVD, 338 patients with both tumor and CVD, and 322 controls. APOE polymorphisms were determined by genotyping assay. The factors influencing tumor patients with or without CVD were also analyzed by logistic regression analysis.

Results

The present study involved different types of solid tumors. Lung cancer was the most common cancer (20.2%, 151/747), followed by colorectal (17%, 127/747), esophageal (9.8%, 73/747), and liver (8.7%, 65/747) cancers. E3/E3 was the most frequent genotype, and ɛ3 was the greatest allele frequency in our study population. The frequencies of the E3/E3, E3/E4, E2/E3, E2/E4, E4/E4, and E2/E2 genotypes in tumor patients were 76.97% (575/747), 14.19% (106/747), 6.83% (51/747), 1.2% (9/747), 0.4% (3/747), and 0.4% (3/747), respectively. Tumor patients carrying ε3 with or without CVD showed higher levels of TG, TC, and LDL-C and lower levels of HDL-C compared to the controls carrying ε3. On the other hand, the tumor patients carrying ε4 with or without CVD showed higher levels of TG and LDL-C and lower levels of HDL-C (all P < 0.05). The frequency of APOE ε4 allele and the E3/E4 genotype was relatively greater in tumor or CVD patients (P < 0.001). In addition, ε4 allele acted as an independent risk factor for tumor patients group (P = 0.037, adjusted OR = 1.92, 95% CI 1.04–3.55) and tumor + CVD patients group (P = 0.012, adjusted OR = 2.53, 95% CI 1.22–5.23).

Conclusions

Individuals carrying ε4 are at a higher risk of tumor with or without CVD, and APOE polymorphisms affect the serum lipid profiles.

Glycosylation and its research progress in endometrial cancer

Endometrial cancer (EC) is one of the most common tumors in the female reproductive system, which seriously threatens women's health, particularly in developed countries. 13% of the patients with EC have a poor prognosis due to recurrence and metastasis. Therefore, identifying good predictive biomarkers and therapeutic targets is critical to enable the early detection of metastasis and improve the prognosis. For decades, extensive studies had focused on glycans and glycoproteins in the progression of cancer. The types of glycans that are covalently attached to the polypeptide backbone, usually via nitrogen or oxygen linkages, are known as N‑glycans or O‑glycans, respectively. The degree of protein glycosylation and the aberrant changes in the carbohydrate structures have been implicated in the extent of tumorigenesis and reported to play a critical role in regulating tumor invasion, metabolism, and immunity. This review summarizes the essential biological role of glycosylation in EC, with a focus on the recent advances in glycomics and glycosylation markers, highlighting their implications in the diagnosis and treatment of EC.

Circulating HDL and Non-HDL Associated Apolipoproteins and Breast Cancer Severity

Plasma lipids are carried within lipoproteins with various apolipoprotein content. This study evaluates the interest of measuring the apolipoproteins of circulating lipoproteins in breast cancer. Patients with early-stage breast cancer (n = 140) were included. Tumors differed by the expression of estrogen and progesterone receptor (HR- and HR+ for negative and positive expression) and the proliferation marker Ki-67 (≤20% or ≥30%). Apolipoprotein concentrations were determined in plasma, HDL and non-HDL fractions, and results are given in mg/dL, median (25th-75th). Patients did not differ in their plasma and lipoprotein lipid concentrations. HDL apoC-I and non-HDL apoC-II were reduced (1.34 (1.02-1.80) vs. 1.61 (1.32-2.04), p = 0.04; 0.31 (0.18-0.65) vs. 0.63 (0.39-1.02), p = 0.01; respectively), in RH-/high Ki-67 patients in comparison to RH-/low Ki-67 patients, while plasma apoD and HDL apoD were higher (3.24 (2.99-4.16) vs. 3.07 (2.39-3.51), p = 0.04; 2.74 (2.36-3.35) vs. 2.45 (2.01-2.99), p = 0.04; respectively). When RH+/high Ki-67 patients were compared with RH+/low Ki-67 patients, HDL apoC-I and HDL apoC-III were higher (1.56 (1.20-1.95) vs. 1.35 (1.10-1.62), p = 0.02; 2.80 (2.42-3.64) vs. 2.38 (1.69-2.96), p = 0.02; respectively). The distribution of exchangeable apolipoproteins, such as apoC-I, apoC-II, apoC-III, apoD, between lipoproteins is linked to the severity of breast cancer.

The Role of ApoE Expression and Variability of Its Glycosylation in Human Reproductive Health in the Light of Current Information

Apolipoprotein E (ApoE), a 34-kDa glycoprotein, as part of the high-density lipoprotein (HDL), has antioxidant, anti-inflammatory and antiatherogenic properties. The variability of ApoE expression in the course of some female fertility disorders (endometriosis, POCS), and other gynecological pathologies such as breast cancer, choriocarcinoma, endometrial adenocarcinoma/hyperplasia and ovarian cancer confirm the multidirectional biological function of ApoE, but the mechanisms of its action are not fully understood. It is also worth taking a closer look at the associations between ApoE expression, the type of its genotype and male fertility disorders. Another important issue is the variability of ApoE glycosylation. It is documented that the profile and degree of ApoE glycosylation varies depending on where it occurs, the type of body fluid and the place of its synthesis in the human body. Alterations in ApoE glycosylation have been observed in the course of diseases such as preeclampsia or breast cancer, but little is known about the characteristics of ApoE glycans analyzed in human seminal and blood serum/plasma in the context of male reproductive health. A deeper analysis of ApoE glycosylation in the context of female and male fertility will both enable us to broaden our knowledge of the biochemical and cellular mechanisms in which glycans participate, having a direct or indirect relationship with the fertilization process, and also give us a chance of contributing to the enrichment of the diagnostic panel in infertile women and men, which is particularly important in procedures involved in assisted reproductive techniques. Moreover, understanding the mechanisms of glycoprotein glycosylation related to the course of various diseases and conditions, including infertility, and the interactions between glycans and their specific ligands may provide us with an opportunity to interfere with their course and thus develop new therapeutic strategies. This brief overview details some of the recent advances, mainly from the last decade, in understanding the associations between ApoE expression and some female and male fertility problems, as well as selected female gynecological diseases and male reproductive tract disorders. We were also interested in how ApoE glycosylation changes influence biological processes in the human body, with special attention to human fertility.

Apolipoproteins, as the carrier proteins for lipids, are involved in the development of breast cancer

Apolipoproteins, the key components of lipoproteins, play vital roles in the combination and transportation of lipids. Numerous research articles have accumulated solid evidence that lipoproteins are closely related to various types of tumorigenesis. In this review, we focused on the associations between several apolipoproteins and breast carcinoma and distinguished the effects and significance of apolipoproteins in different locations to validate their roles in breast carcinoma development. For example, apoD and apoE in serum are viewed as risk factors for breast carcinoma. ApoD, apoE and apoA-I in mammary tissues inhibit tumor growth. Moreover, apoB, apoJ and apoA-I have the potential to function as diagnostic or prognostic markers in the clinic. ApoEdp and apoJ treatment on breast carcinoma could significantly restrict tumor growth. In general, the aim of this review was to further analyze the associations between some members of the apolipoprotein family and breast cancer.

FAK-ERK activation in cell/matrix adhesion induced by the loss of apolipoprotein E stimulates the malignant progression of ovarian cancer

Background

Extracellular matrix (ECM) is a mediator of tumor progression. However, whether the alterations of the intraperitoneal ECM prior to tumor establishment affects the malignant progression of ovarian cancer remains elusive.

Methods

Apolipoprotein (ApoE) knock-out mice was used to analyze the intraperitoneal ECM alterations by quantification of the major components of ECM. ID8 cells were implanted in vivo to generate allografts and human ovarian cancer cell lines were characterized in vitro to assess the effects of ECM alterations on the malignant progression of ovarian cancer. Adhesion assay, immunochemistry, cytokines profile, proliferation assay, transwell invasion assay and western blot were used to determine the malignant phenotype of ovarian cancer cells.

Results

ApoE loss induced increased ECM deposition, which stimulated the adhesions of ovarian cancer cells. The adhesion-mediated focal adhesion kinase (FAK) signaling enhanced the invasive behaviors of ovarian cancer cells through activation of a ERK-MMP linkage. This ECM-induced signaling cascade was further confirmed in human ovarian cancer cell lines in vitro. Furthermore, reversal of the ECM accumulation with BAPN or abrogation of adhesion-induced ERK activation in ovarian cancer cells with MEK inhibitors (MEKi) was found to effectively delay ovarian cancer progression.

Conclusions

These findings identify the FAK-ERK activation in cell/matrix adhesion in the malignant progression of ovarian cancer and the efficiency of BAPN or MEKi for tumor suppression, providing an impetus for further studies to explore the possibility of new anticancer therapeutic combinations.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0696-4) contains supplementary material, which is available to authorized users.

The relationship between apolipoprotein E gene ε2/ε3/ε4 polymorphism and breast cancer risk: a systematic review and meta-analysis

Objective

We conducted a systematic review and meta-analysis aiming to assess the relationship between apolipoprotein E (APOE) gene ε2/ε3/ε4 polymorphism and breast cancer risk.

Methods

Yun-Long Liu and Hao-Min Zhang independently completed literature retrieval and data collection, and statistical analyses were performed by Stata. Individual odds ratio (OR) and 95% confidence interval (CI) were pooled in a random-effects model using the DerSimonian–Laird method. Heterogeneity was evaluated by I² statistic at a significance level of 50%. Publication bias was assessed by Egger’s test.

Results

Eleven articles including 2,074 breast cancer patients and 2,372 controls were summarized. Using the most common allele ε3 as a reference, the ε2 (OR =0.87, 95% CI =0.72–1.05, P=0.154, I²=0.0%) and ε4 (OR =1.07, 95% CI =0.80–1.42, P=0.654, I²=71.8%) alleles were not found to be significantly associated with breast cancer risk in the overall analyses. Subgroup analyses revealed that the comparison of allele ε4 with ε3 was significant in Asians (OR =1.58, 95% CI =1.17–6.32, P=0.003, I²=12.1%) and in studies that used the restriction fragment length polymorphism (RFLP) genotyping method (OR =1.27; 95% CI =1.01–1.61, P=0.045, I²=34.3%), and was marginally significant in hospital-based studies (OR =1.33; 95% CI =0.98–1.79, P=0.065, I²=30.2%), without heterogeneity. Moreover, the presence of the ε2 allele was significantly associated with breast cancer in small studies (total sample size <500) (OR =0.73, 95% CI =0.54–1.00, P=0.052, I²=0.0%) without heterogeneity. The Egger’s test indicated low probabilities of publication bias.

Conclusion

We observed a significant association between APOE gene ε4 allele and breast cancer risk in Asian populations. Moreover, the findings of our subgroup analyses suggest that source of controls, genotyping platform, and sample size might be the potential causes of heterogeneity.

Apolipoprotein E epsilon 2 allele and low serum cholesterol as risk factors for gastric cancer in a Chinese Han population

Apolipoprotein E (apoE) mediates lipid metabolism both in peripheral and in the brain. The human APOE gene has three polymorphic alleles that influence the risk for various types of cancer and neurodegenerative diseases. A potential association between APOE allele and the risk for gastric cancer has been implicated, but the specific allele involved and potential associations with the subtype and the grade of cancer malignancy need further clarification. We screened the APOE genotype in 550 gastric cancer patients and 550 non-cancer control individuals and found that the presence of the APOE ε2 and lower serum total cholesterol are associated with an increased risk for gastric cancer (all P ≤ 0.0005). Interestingly, APOE ε2 is also correlated with increased risk for both intestinal and diffuse histotypes but not with TN classification or stage in gastric cancer patients, suggesting that APOE polymorphic alleles are associated with the risk of development but unlikely the progression of gastric cancer. Since ε2 carriers have lower levels of serum total cholesterol than non-ε2 carriers, our findings suggest that the increased risk for gastric cancer by APOE ε2 allele might be mediated through lowered serum total cholesterol levels.

Obesity and Diabetes: The Increased Risk of Cancer and Cancer-Related Mortality

Obesity and type 2 diabetes are becoming increasingly prevalent worldwide, and both are associated with an increased incidence and mortality from many cancers. The metabolic abnormalities associated with type 2 diabetes develop many years before the onset of diabetes and, therefore, may be contributing to cancer risk before individuals are aware that they are at risk. Multiple factors potentially contribute to the progression of cancer in obesity and type 2 diabetes, including hyperinsulinemia and insulin-like growth factor I, hyperglycemia, dyslipidemia, adipokines and cytokines, and the gut microbiome. These metabolic changes may contribute directly or indirectly to cancer progression. Intentional weight loss may protect against cancer development, and therapies for diabetes may prove to be effective adjuvant agents in reducing cancer progression. In this review we discuss the current epidemiology, basic science, and clinical data that link obesity, diabetes, and cancer and how treating obesity and type 2 diabetes could also reduce cancer risk and improve outcomes.

Analysis of differentially expressed novel post-translational modifications of plasma apolipoprotein E in Taiwanese females with breast cancer

APOE ε2 or ε4 alleles being used as indicators of breast cancer risk are controversial in Taiwanese females. We provide a concept for relative comparisons of post-translational modifications (PTMs) of plasma apolipoprotein E (ApoE) between normal controls and breast cancer patients to investigate the association of ApoE with breast cancer risk. APOE polymorphisms (ApoE isoforms) were not assessed in this study. The relative modification ratio (%) of 15 targeted and 21 modified peptides were evaluated by 1D SDS-PAGE, in-gel digestion, and label-free nano-LC/MS to compare normal controls with breast cancer patients. Plasma levels of the ApoE protein did not significantly differ between normal controls and breast cancer patients. Eleven sites with novel PTMs were identified from 7 pairs of differentially expressed targeted and modified peptides according to the relative modification ratio including methylation at the E3 (↑1.45-fold), E7 (↑1.45-fold), E11 (↑1.19-fold), E77 (↑2.02-fold), E87 (↑2.02-fold), and Q98 (↑1.62-fold) residues; dimethylation at the Q187 (↑1.44-fold) residue; dihydroxylation at the R92 (↑1.25-fold), K95 (↑1.25-fold), and R103 (↑1.25-fold) residues; and glycosylation at the S129 (↑1.14-fold) residue. The clustered methylation and dihydroxylation of plasma ApoE proteins may play a role in breast cancer.

Causal relevance of circulating high-density lipoprotein cholesterol with cancer: a Mendelian randomization meta-analysis

We summarized published data on the associations of apolipoprotein E (APOE) gene ε2/ε3/ε4 polymorphism with both cancer risk and circulating lipid profiles, aiming to examine the causal relevance between lipids and cancer risk. Article identification and data abstraction were conducted in duplicate and independently by two authors. Data were analyzed by STATA software. Twenty-five articles that examined the associations of APOE gene ε2/ε3/ε4 polymorphism with either cancer risk (n = 22) or circulating lipid changes (n = 4) were eligible. The presence of ε2 and ε4 alleles showed no overall associations with overall cancer risk when compared with ε3 allele. The ε4 allele was significantly associated with 1.40-fold (odds ratio or OR = 1.40; 95% confidence interval or CI: 1.00–1.94; P = 0.047) increased risk of developing cancer in Asian populations, and the presence of heterogeneity was low (I² = 37.6%). Carriers of ε3/ε4 genotype had a significant reduction in circulating HDL-C (WMD = −2.62; 95% CI: −4.19 to −1.04; P = 0.001) without heterogeneity (I² = 16.6%). The predicted odds of having cancer for 1 mg/dL reduction in circulating HDL-C was 1.14 (95% CI: 1.00 to 1.89). The findings of this Mendelian randomization meta-analysis demonstrate that reduced circulating HDL-C might be a potentially causal risk factor for the development of overall cancer in Asians.

A comparitive study to evaluate the role of serum lipid levels in aetiology of carcinoma breast

INTRODUCTION

Breast cancer is the most common occurring cancer in women worldwide. Various factors that have lead to change in lifestyle are thought to be associated with increase in breast cancer incidence in Asian countries. Several clinical studies suggest the prognostic significance of serum lipid levels in breast cancer. Present study was planned to confirm the association of lipids levels with breast cancer.

MATERIALS AND METHODS

Lipid analyses was carried out on serum samples from 100 breast cancer patients and 100 control women, with a age group of 25 y and above. The case & control group included 50 premenopausal women and 50 postmenopausal women.

RESULTS

Patients of study group had high Low density lipoproteins (LDL) (p-value - 0.00), Triglycerides (TG) (p-value -0.001) and Total cholesterol (TC) (p-value -0.00) as compared to control group. There was no association of VLDL (p-value -0.436) and HDL (p-value -0.797) among study group and control group. There was no association of lipid levels in different grades of carcinoma.

CONCLUSION

High levels of LDL, TG and TC were associated with breast cancer. However, no association was there in different grades of carcinoma. So it may be concluded that, LDL, TG and TC may be having some role in aetiology of breast cancer. Therefore, early detection and control of these factors may help in reducing the incidence of breast cancer and ultimately social and economic burden on society.

Apolipoprotein E genetic polymorphism, serum lipoprotein levels and breast cancer risk: A case-control study

The purpose of this study was to evaluate the association between apolipoprotein E (APOE) allelic frequency, serum lipoproteins and breast cancer (BC). We conducted a nested case-control study within a cohort including 47 cases and 165 controls. Polymerase chain reaction-restriction fragment length polymorphism analyses of the APOE polymorphism were performed. In general, participants with the genotype including alleles e2 and e3 tended to have lower serum triglycerides, total cholesterol and low-density lipoprotein cholesterol levels and higher high-density lipoprotein (HDL) cholesterol levels compared to participants homozygous for the e3 allele and participants heterozygous for the e3 and e4 alleles, respectively. BC patients exhibited higher mean levels of total serum cholesterol (P=0.070), dietary fat intake (P=0.020) and dietary cholesterol intake (P=0.017) compared to control subjects. The allelic distribution between the two groups revealed that the presence of the e2 allele was positively associated with the absence of BC, whereas the e4 allele was positively associated with the BC case group (P=0.019). The distribution of the APOE genotypes was not significantly different between cases and controls (P=0.172). The concomitant presence of the e2 and e4 alleles was positively associated with the absence of BC and e4/e4 homozygosity was positively associated with BC (P=0.021). Our findings suggested that APOE polymorphism plays an important role in the development of BC, particularly when associated with higher serum triglyceride levels.

Association between apolipoprotein E genotype and cancer susceptibility: a meta-analysis

BACKGROUND

Apolipoprotein E (ApoE), a protein primarily involved in lipoprotein metabolism, occurs in three isoforms (E2, E3 and E4). Studies evaluating the association between APOE genotype and incidence of malignancies have given inconclusive results.

OBJECTIVE

The objective of the present study was to analyze the association between APOE genotype and incidence of cancer by a meta-analysis.

METHODS

We conducted a literature search in the electronic databases for studies with information on APOE genotype in malignancies. Sixteen studies (14 case-control and 2 cohort; 77,970 controls and 12,010 cases) were included for the present meta-analysis. Pooled odds ratios (OR) with 95 % confidence intervals (CI) were calculated assuming a random-effect model for all the genotypes and alleles. Subgroup analyses based on study design, ethnicity of populations, site of cancer and source of controls were performed as a post hoc measure. Appropriate tests to detect heterogeneity, publication bias and sensitivity were done at all stages. The review protocol is registered with the PROSPERO database vide registration number CRD42013006496.

RESULTS

The pooled effect measure for the comparisons did not reveal an association in primary analyses. In the subgroup analyses, we observed a negative association between APOE4+ genotypes and overall risk of cancer in the cohort study subgroup (pooled OR 0.86; 95 % CI 0.82-0.91; p < 0.00001; I (2) = 0 %). Sensitivity analyses did not alter the overall pooled effect measure, and there were no evidences to suggest a publication bias.

CONCLUSION

Overall, the present meta-analysis did not show any association between APOE alleles and genotypes with incidence of cancer in general.

Tamoxifen therapy in breast cancer: do apolipoprotein E genotype and menopausal state affect plasma lipid changes induced by the drug?

OBJECTIVE

This study examines the lipid profile change produced in response to tamoxifen (TAM) treatment, and its possible relationship with both apolipoprotein E genotype and menopausal state in patients with breast cancer.

METHODS

Blood samples were collected from 86 Spanish women with breast cancer before initiating TAM treatment and in the following 6, 12 and 18 months of treatment. Plasma lipid levels (total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol) were determined using an automatic analyzer. Genotypes for apolipoprotein E (ApoE) were identified by PCR-RFLP using the HhaI enzyme.

RESULTS

In all patients, significant reductions in total cholesterol and LDL-cholesterol concentrations and a significant increase in triglyceride concentrations were observed after 6, 12, and 18 months of TAM treatment compared to baseline (p<0.01 for each time point). In the subset of APOE4-negative patients, triglyceride concentrations also significantly increased after 6, 12, and 18 months of treatment (p=0.019, p=0.045, p=0.001, respectively), while APOE4-positive patients showed no significant lipid changes at 12 and 18 months. However, after 18 months of TAM treatment the overall triglyceride concentrations had risen by 24.75% in APOE4-negative patients vs 29.9% in APOE4-positive patients. In postmenopausal women, significant reductions in total cholesterol, LDL-cholesterol and LDL/HDL ratios were observed at each time point (p<0.020 for each).

CONCLUSIONS

TAM treatment induced similar plasma triglyceride increases in patients with positive or negative APOE genotype. Compared to premenopausal patients, postmenopausal breast cancer patients showed a more beneficial lipid profile change in response to treatment.

Cognitive effects of cancer and its treatments at the intersection of aging: what do we know; what do we need to know?

There is a fairly consistent, albeit non-universal body of research documenting cognitive declines after cancer and its treatments. While few of these studies have included subjects aged 65 years and older, it is logical to expect that older patients are at risk of cognitive decline. Here, we use breast cancer as an exemplar disease for inquiry into the intersection of aging and cognitive effects of cancer and its therapies. There are a striking number of common underlying potential biological risks and pathways for the development of cancer, cancer-related cognitive declines, and aging processes, including the development of a frail phenotype. Candidate shared pathways include changes in hormonal milieu, inflammation, oxidative stress, DNA damage and compromised DNA repair, genetic susceptibility, decreased brain blood flow or disruption of the blood-brain barrier, direct neurotoxicity, decreased telomere length, and cell senescence. There also are similar structure and functional changes seen in brain imaging studies of cancer patients and those seen with "normal" aging and Alzheimer's disease. Disentangling the role of these overlapping processes is difficult since they require aged animal models and large samples of older human subjects. From what we do know, frailty and its low cognitive reserve seem to be a clinically useful marker of risk for cognitive decline after cancer and its treatments. This and other results from this review suggest the value of geriatric assessments to identify older patients at the highest risk of cognitive decline. Further research is needed to understand the interactions between aging, genetic predisposition, lifestyle factors, and frailty phenotypes to best identify the subgroups of older patients at greatest risk for decline and to develop behavioral and pharmacological interventions targeting this group. We recommend that basic science and population trials be developed specifically for older hosts with intermediate endpoints of relevance to this group, including cognitive function and trajectories of frailty. Clinicians and their older patients can advance the field by active encouragement of and participation in research designed to improve the care and outcomes of the growing population of older cancer patients.

Frontal gray matter reduction after breast cancer chemotherapy and association with executive symptoms: a replication and extension study

Cognitive changes related to cancer and its treatment have been intensely studied, and neuroimaging has begun to demonstrate brain correlates. In the first prospective longitudinal neuroimaging study of breast cancer (BC) patients we recently reported decreased gray matter density one month after chemotherapy completion, particularly in frontal regions. These findings helped confirm a neural basis for previously reported cognitive symptoms, which most commonly involve executive and memory processes in which the frontal lobes are a critical component of underlying neural circuitry. Here we present data from an independent, larger, more demographically diverse cohort that is more generalizable to the BC population. BC patients treated with (N=27) and without (N=28) chemotherapy and matched healthy controls (N=24) were scanned at baseline (prior to systemic treatment) and one month following chemotherapy completion (or yoked intervals for non-chemotherapy and control groups) and APOE-genotyped. Voxel-based morphometry (VBM) showed decreased frontal gray matter density after chemotherapy, as observed in the prior cohort, which was accompanied by self-reported difficulties in executive functioning. Gray matter and executive symptom changes were not related to APOE ε4 status, though a somewhat greater percentage of BC patients who received chemotherapy were ε4 allele carriers than patients not treated with chemotherapy or healthy controls. These findings provide confirmatory evidence of frontal morphometric changes that may be a pathophysiological basis for cancer and treatment-related cognitive dysfunction. Further research into individual risk factors for such changes will be critical for development of treatment and prevention strategies.

Peroxisome proliferator activated receptor-α/hypoxia inducible factor-1α interplay sustains carbonic anhydrase IX and apoliprotein E expression in breast cancer stem cells

AIMS

Cancer stem cell biology is tightly connected to the regulation of the pro-inflammatory cytokine network. The concept of cancer stem cells "inflammatory addiction" leads to envisage the potential role of anti-inflammatory molecules as new anti-cancer targets. Here we report on the relationship between nuclear receptors activity and the modulation of the pro-inflammatory phenotype in breast cancer stem cells.

METHODS

Breast cancer stem cells were expanded as mammospheres from normal and tumor human breast tissues and from tumorigenic (MCF7) and non tumorigenic (MCF10) human breast cell lines. Mammospheres were exposed to the supernatant of breast tumor and normal mammary gland tissue fibroblasts.

RESULTS

In mammospheres exposed to the breast tumor fibroblasts supernatant, autocrine tumor necrosis factor-α signalling engenders the functional interplay between peroxisome proliferator activated receptor-α and hypoxia inducible factor-1α (PPARα/HIF1α). The two proteins promote mammospheres formation and enhance each other expression via miRNA130b/miRNA17-5p-dependent mechanism which is antagonized by PPARγ. Further, the PPARα/HIF1α interplay regulates the expression of the pro-inflammatory cytokine interleukin-6, the hypoxia survival factor carbonic anhydrase IX and the plasma lipid carrier apolipoprotein E.

CONCLUSION

Our data demonstrate the importance of exploring the role of nuclear receptors (PPARα/PPARγ) in the regulation of pro-inflammatory pathways, with the aim to thwart breast cancer stem cells functioning.

Apolipoprotein E (APOE) Polymorphisms and Susceptibility to Breast Cancer: A Meta-Analysis

Purpose

Apolipoprotein E (APOE, MIM: 107741) has three functionally distinct isoforms of the protein (E2, E3, and E4), encoded by corresponding alleles ε2, ε3, and ε4, which have been well described. Findings from previous studies investigating association between APOE polymorphisms and breast cancer risk have been inconsistent. The present meta-analysis was conducted in order to investigate association of APOE polymorphisms with risk of breast cancer.

Materials and Methods

Several electronic databases were used for identification of studies containing information on APOE polymorphisms and breast cancer risk published up to January 2012. We identified 10 eligible studies, including 3,835 subjects (2008 patients, and 1,827 healthy controls), that reported on polymorphisms of APOE and risk of breast cancer. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using a fixed and random-effects models.

Results

Among studies reported from Asia, an association of the ε4 allele with increased risk of breast cancer, in comparison with the ε3 allele, was observed (OR, 1.56; 95% CI, 1.19 to 2.04; p=0.001). It should be noted that allele ε2 showed no association with breast cancer risk. Among Caucasians, neither the ε4 (OR, 0.99; 95% CI, 0.83 to 1.17; p=0.917) nor the ε2 (OR, 0.92; 95% CI, 0.72 to 1.17; p=0.514) allele showed an association with susceptibility to breast cancer, when compared with the ε3 allele. Carriers of the ε4 allele (E4E4, E4E3, and E4E2 genotypes), in comparison with the E3E3 genotype, showed an association with elevated risk of breast cancer only among Asians (OR, 1.75; 95% CI, 1.23 to 2.47; p=0.002). No publication bias was detected.

Conclusion

This meta-analysis suggest that the APOEε4 allele is a low-penetrant risk factor for development of breast cancer.

Apolipoprotein E Allelic Frequency Altered in Women with Early-onset Breast Cancer

Among women, the most prevalent type of cancer is breast cancer, affecting 1 out of every 8 women in the United States; in Puerto Rico, 70 out of every 100,000 will develop some type of breast cancer. Therefore, a better understanding of the potential risk factors for breast cancer could lead to the development of early detection tools. A gene that has been proposed as a risk factor in several populations around the world is Apolipoprotein E (apoE). ApoE functions as a mechanism of transport for lipoproteins and cholesterol throughout the body, with 3 main isoforms present in humans (apoE2, apoE3, and apoE4). Whether or not apoE4 is a risk factor for breast cancer remains controversial. Previous studies have either included test subjects of all ages (20–80) or have focused on late-onset (after age 50) breast cancer; none has concentrated specifically on early-onset (aged 50 and younger) breast cancer. The objectives of this study was to examine (in a Puerto Rican population) the differences in the relative frequency of occurrence of apoE4 in non-breast cancer versus breast cancer patients and to examine, as well, the potential differences of same in early- versus late-onset patients. We found an increased frequency of apoE4 (odds ratio 2.15) only in early-onset breast cancer survivors, which is similar to the findings of those studies that combined or adjusted for age as well as for an association between apoE4 and decreased tumor size. ApoE is also a potential risk factor for long-term cognitive effects after chemotherapy and affects response to hormone replacement. Our data supports the theory that knowing the apoE genotype of women who are at risk of developing breast cancer may be beneficial, as such knowledge would aid in the prediction of tumor size and the development of treatment regimens.

Serum lipid profile of breast cancer patients

The purpose of this study was to carry out a comparative study to investigate the effect of lipid profile, oestradiol and obesity on the risk of a woman developing breast cancer. This study was carried out at the Komfo Anokye Teaching Hospital (KATH), Peace and Love Hospital, Oduom, Kumasi and Redeemed Clinic, Nima, Accra between May 2002 and March 2003. In this study, 200 consented women comprising 100 breast cancer patients (43 pre- and 57 post-menopausal) and 100 controls (45 pre- and 55 post-menopausal) with similar age range (25 to 80 years) were assessed for lipid profile, oestradiol and BMI. There was a significant increase in Body Mass Index (BMI) (p = 0.011), Total Cholesterol (TC) (p < 0.001), triglyceride (p = 0.026) and low density lipoprotein (LDL-cholesterol) (p = 0.001) of the breast cancer patients compared to the controls. With the exception of oestradiol (EST) that decreased, the lipid profile generally increased with age in both subjects and controls with the subjects having a much higher value than the corresponding control. There was also a significant positive correlation between BMI and TC (r2 = 0.022; p = 0.002) and also between BMI and LDL-cholesterol (r2 = 0.031; p = 0.0003). Apart from EST and LDL-cholesterol that were increased significantly only in the postmenopausal phase in comparison to the controls, BMI, TC and TG were increased in both pre-menopausal and post menopausal phases with HDL-cholesterol remaining unchanged. This study confirms the association between dyslipidaemia, BMI and increased breast cancer risk.

A longitudinal study of the metabolic syndrome and risk of postmenopausal breast cancer

The metabolic syndrome, characterized by abdominal obesity, high blood glucose levels, impaired glucose tolerance, dyslipidemia, and hypertension, is associated with increased risk of type 2 diabetes and coronary heart disease. Several studies have examined the association of the individual components of the metabolic syndrome with breast cancer; to date, however, no study has assessed the metabolic syndrome per se in relation to breast cancer risk. Furthermore, previous studies have relied only on baseline assessment of components of the syndrome. Therefore, we assessed the association of the metabolic syndrome with the risk of postmenopausal breast cancer among women in the 6% sample of subjects in the Women's Health Initiative clinical trial and the 1% sample of women in the observational study who had repeated measurements of the components of the syndrome during follow-up. We used Cox proportional hazards models to estimate hazard ratios and 95% confidence intervals for the association of breast cancer risk with the presence of the metabolic syndrome, as well as its components, at baseline and in time-dependent analyses. After exclusion of women with diabetes, among 4,888 women with baseline measurements, 165 incident cases of breast cancer were ascertained over a median of 8 years of follow-up. The presence of the metabolic syndrome at baseline was not associated with altered risk. Of the individual components measured at baseline, diastolic blood pressure showed a borderline positive association with breast cancer. In time-dependent covariate analyses, however, certain scenarios indicated a positive association between the metabolic syndrome and breast cancer, due primarily to positive associations with serum glucose, serum triglycerides, and diastolic blood pressure.

Apolipoprotein E4 allele influences the response of plasma triglyceride levels to tamoxifen in breast cancer patients

BACKGROUND

Apolipoprotein E4 (APOE4) allele is an important risk factor for breast cancer and affects clearance of chylomicron remnants. Tamoxifen therapy increases serum triglyceride levels and sometimes inducing severe hypertriglyceridemia in breast cancer patients.

METHODS

Thirty-three women with breast cancer were recruited to examine the APOE polymorphism and fasting plasma lipid profiles before and after tamoxifen treatment for 6 months.

RESULTS

We found that plasma lipid profiles changed in accordance with the APOE4 allele after tamoxifen treatment for 6 months. Especially plasma triglyceride levels significantly decreased in the APOE4-positive patients (p=0.025), while there was no change in APOE4-negative patients (p=0.189). The total plasma cholesterol levels were reduced in APOE-4 positive patients after 6-month tamoxifen treatment (p=0.014). The levels of plasma low density lipoprotein cholesterol and high density lipoprotein cholesterol significantly decreased in both APOE4-negative and APOE4-positive patients.

CONCLUSIONS

These findings indicate that the effects of tamoxifen on plasma triglyceride levels are modified by APOE polymorphism. Breast cancer patients with APOE4 allele have low plasma triglyceride levels when receiving tamoxifen therapy. Therefore, we suggest that APOE gene polymorphism is a critical validation before tamoxifen treatment in breast cancer patients.

Association between the apolipoprotein E genotypes and breast cancer patients in Taiwanese

To display the association between the apolipoprotein E (APOE) genotypes and breast cancer patients, a cross sectional study including 291 patients and 148 controls was performed. The APOE genotypes were measured in all participants, and the pathological diagnosis, estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 (HER-2) among breast cancer patients were collected. The results showed the APOE allele frequency in breast cancer patients was 11.7% epsilon2 carriers, 74.6% epsilon3 carriers and 13.7% epsilon4 carriers, and there was no significant difference when they were compared with those of the control group (15.5% epsilon2 carriers, 74.3% epsilon3 carriers and 10.1% epsilon4 carriers; p=0.342). Among the patients in pre-menopause, showed a higher frequency of epsilon2 carriers had the cancer site on the left than that of the epsilon3 carriers (78.6% versus 40.3%; p=0.019). Among breast cancer patients, there was no significant association between the APOE genotypes and menopausal status, pathological diagnosis, estrogen receptor, progesterone receptor, and HER-2. Our findings demonstrated that the APOE genotypes were not associated with breast cancer patients, and epsilon2 allele tended to induce breast cancer on the left site among those patients in pre-menopause.

Influences of apolipoprotein E polymorphism on the risk for breast cancer and HER2/neu status in Taiwan

Apolipoprotein E (APOE) polymorphism plays an important role in lipid metabolism. Preliminary evidence suggests that APOE genotype appears to be a risk factor for not only cardiovascular disease, but also Alzheimer's disease and cancer. We screened the APOE genotype in 290 breast cancer patients and 232 non-cancer controls and determined the relationship between APOE gene polymorphism and breast cancer in Taiwan. We found risk for breast cancer was associated with the APOE genotype (xi(2) = 8.652, p = 0.013). Carriers of the epsilon4 allele were more common in breast cancer cases than carriers of epsilon3 allele (p = 0.004, OR = 1.786, 95% CI: 1.197-2.664). In addition, the epsilon4 allele is also associated with HER2/neu negative status in breast cancer patients (p = 0.006, OR = 0.277, 95% CI: 0.111-0.693). No significant associations between APOE genotype and tumor grade, TN classification, progesterone receptor, estrogen receptor, lymphatic invasion, or recurrence of breast cancer were in evidence. These results suggest that the APOE epsilon4 allele may be a risk factor for breast cancer and correlates with HER2/neu negative status.

Associations between apoE genotype and colon and rectal cancer

Apolipoprotein E (apoE) plays a major role in the metabolism of bile acids, cholesterol and triglycerides, and has recently been proposed as being involved in the carcinogenic process. Given the potential role of bile acids in colorectal cancer etiology, it is reasonable that colorectal cancer risk might be modified by apoE genotype. We used data collected from a case-control study of colon cancer (n=1556 cases and 1948 controls) and rectal cancer (n=777 cases and 988 controls). The absence of an e3 apoE allele significantly increased the risk of colon cancer (OR=1.37 95% CI 1.00-1.87), particularly among those diagnosed when older than 64 years (OR=1.88 95% CI 1.17-3.04; P interaction between age and apoE genotype equal to 0.05). A significant three-way interaction was detected for family history of colorectal cancer, age at diagnosis and apoE genotype (P = 0.05), in those diagnosed when older, not having an e3 allele and having a significantly increased risk of colon cancer with family history of colorectal cancer (OR=3.93 95% CI 1.23-12.6). This was compared with the risk associated with family history of colorectal cancer among those diagnosed when older, with an e3 allele of 1.61 (95% CI 1.17-2.23) or those diagnosed when younger without an e3 allele (OR=2.40 95% CI 0.56-10.3). Among those diagnosed when older than 64 years, associations of BMI and prudent diet with colon cancer were stronger among individuals without an e3 allele, although the P for interaction was not significant. We did not detect any significant associations between apoE genotype and rectal cancer, survival after diagnosis with colorectal cancer, stage of disease at diagnosis or type of tumor mutation. These findings suggest those apoE genotypes that do not include the e3 allele, the same genotypes that are associated with increased risk of coronary heart disease, may influence development of colon cancer among those who are older at diagnosis.

Improvement of metabolism among obese breast cancer survivors in differing weight loss regimens

OBJECTIVE

To compare the efficacy of different weight loss regimens on body weight loss and metabolic improvement in breast cancer survivors.

RESEARCH METHODS AND PROCEDURES

Forty-eight obese breast cancer survivors were randomly divided into four groups and were followed for 1 year: 1) the Control group (subjects did not receive specific nutrition counseling); 2) the Weight Watchers group (subjects were given free coupons to attend weekly Weight Watchers meetings); 3) the Individualized group (a registered dietitian provided one-on-one nutritional counseling); and 4) the Comprehensive group (subjects received individualized dietary counseling and free coupons for the weekly Weight Watchers meetings). At baseline and 3-, 6-, and 12-month data collection visits, a fasting blood sample was obtained for assays. A three-day dietary record was kept during the week before these visits and dietary intake was analyzed.

RESULTS

Subjects in the three intervention groups lost weight (Control: 1.1 +/- 1.7 kg; Weight Watchers: -2.7 +/- 2.1 kg; Individualized: -8.0 +/- 1.9 kg; Comprehensive: -9.5 +/- 2.7 kg) and percentage body fat, but only the Individualized and Comprehensive groups had significant losses. Subjects in the Comprehensive group showed the most improvement in cholesterol levels and had reductions in blood leptin levels.

DISCUSSION

Because insulin resistance and high blood leptin levels are associated with breast cancer, losing weight to improve these parameters may reduce the risk of recurrence. Only subjects in the Comprehensive group showed significant reductions in body weight and fat, energy intake, and leptin levels. For breast cancer survivors, different weight loss strategies should be considered to assist them in losing weight.

Association of NQO1 polymorphism with spontaneous breast cancer in two independent populations

Eight different single-nucleotide polymorphisms (SNPs) in six different genes were investigated for possible association with breast cancer. We used a case–control study design in two Caucasian populations, one from Tyrol, Austria, and the other from Prague, Czech Republic. Two SNPs showed an association with breast cancer: R72P inTP53 and P187S in NQO1. Six SNPs, Q356R and P871L in BRCA1, N372H in BRCA2, C112R (E4) and R158C (E2) in ApoE and C825T in GNB3, did not show any sign of association. The P187S polymorphism in NQO1 was associated with breast cancer in both populations from Tyrol and Prague with a higher risk for carriers of the 187S allele. Combining the results of the two populations, we observed a highly significant difference (P=0.0004) of genotype and allele frequencies (odds ratio (OR)=1.46; 95% confidence interval (CI) 1.16–1.85; P=0.001) and of the homozygote ratio (OR=3.8; 95% CI 1.73–8.34; P=0.0001). Combining the two ‘candidate’ SNPs (P187S and R72P) revealed an increased risk for breast cancer of double heterozygotes (P187S/R72P) of the NQO1 and TP53 genes (OR=1.88; 95% CI 1.13–3.15; P=0.011), suggesting a possible interaction of these two loci.

Involvement of apolipoprotein E in glioblastoma: immunohistochemistry and clinical outcome

We hypothesised that apolipoprotein E (apoE) influences brain tumours by delivery of lipids to tumour cells and by analogy with other brain insults. APOE gene analysis was performed for 126 glioblastomas, the commonest primary brain tumour. Neither APOE epsilon2 nor epsilon4 alleles were significantly associated with differences in post-operative survival. However, there was apoE immunoreactivity of tumour cells, macrophages in areas of necrosis and astrocytes nearby. The immunohistochemistry findings support the hypothesis that apoE is involved in the delivery of lipids to tumour cells and in the recycling of lipids by macrophages in necrotic areas, raising the possibility that apoE-mediated lipid transport may represent a new therapeutic target in brain tumours.

Common gene polymorphisms and nutrition: emerging links with pathogenesis of multifactorial chronic diseases (review)

Rapid progress in human genome decoding has accelerated search for the role of gene polymorphisms in the pathogenesis of complex multifactorial diseases. This review summarizes the results of recent studies on the associations of common gene variants with multifactorial chronic conditions strongly affected by nutritional factors. Three main individual sections discuss genes related to energy homeostasis regulation and obesity, cardiovascular disease (CVD), and cancer. It is evident that several major chronic diseases are closely related (often through obesity) to deregulation of energy homeostasis. Multiple polymorphic genes encoding central and peripheral determinants of energy intake and expenditure have been revealed over the past decade. Food intake control may be affected by polymorphisms in the genes encoding taste receptors and a number of peripheral signaling peptides such as insulin, leptin, ghrelin, cholecystokinin, and corresponding receptors. Polymorphic central regulators of energy intake include hypothalamic neuropeptide Y, agouti-related protein, melanocortin pathway factors, CART (cocaine- and amphetamine-regulated transcript), some other neuropeptides, and receptors for these molecules. Potentially important polymorphisms in the genes encoding energy expenditure modulators (alpha- and beta- adrenoceptors, uncoupling proteins, and regulators of adipocyte growth and differentiation) are also discussed. CVD-related gene polymorphisms comprising those involved in the pathogenesis of atherosclerosis, blood pressure regulation, hemostasis control, and homocysteine metabolism are considered in a separate section with emphasis on multiple polymorphisms affecting lipid transport and metabolism and their interactions with diet. Cancer-associated polymorphisms are discussed for groups of genes encoding enzymes of xenobiotic metabolism, DNA repair enzymes, factors involved in the cell cycle control, hormonal regulation-associated proteins, enzymes related to DNA methylation through folate metabolism, and angiogenesis-related factors. There is an apparent progress in the field with hundreds of new gene polymorphisms discovered and characterized, however firm evidence consistently linking them with pathogenesis of complex chronic diseases is still limited. Ways of improving the efficiency of candidate gene approach-based studies are discussed in a short separate section. Successful unraveling of interaction between dietary factors, polymorphisms, and pathogenesis of several multifactorial diseases is exemplified by studies of folate metabolism in relation to CVD and cancer. It appears that several new directions emerge as targets of research on the role of genetic variation in relation to diet and complex chronic diseases. Regulation of energy homeostasis is a fundamental problem insufficiently investigated in this context so far. Impacts of genetic variation on systems controlling angiogenesis, inflammatory reactions, and cell growth and differentiation (comprising regulation of the cell cycle, DNA repair, and DNA methylation) are also largely unknown and need thorough analysis. These goals can be achieved by complex simultaneous analysis of multiple polymorphic genes controlling carefully defined and selected elements of relevant metabolic and regulatory pathways in meticulously designed large-scale studies.

The common polymorphism of apolipoprotein E: geographical aspects and new pathophysiological relations

Apolipoprotein E (apoE) has important functions in systemic and local lipid transport, but also has other functions. The gene (APOE) shows a common polymorphism with three alleles--APOE*2, APOE*3, and APOE*4. Their frequencies vary substantially around the world, but APOE*3 is the most common almost everywhere and is often considered to be the ancestral or "wild-type" allele for that reason. However, there are several arguments for APOE*4 being the ancestral allele. But then, why has APOE*3 become so frequent? And why has APOE*4 not become extinct? The proportion of APOE*4 carriers increases from only 10-15% in southern Europe to 40-50% in the north. The gradient may be a trace of the demic expansion of agriculture that began about 10,000 years ago, but it may also reflect the possibility that APOE*4 carriers are less likely to develop vitamin D deficiency. The common APOE polymorphism is associated with varying risk of cardiovascular disease and Alzheimer's disease, but other interesting aspects may emerge in the future.

'Mendelian randomization': can genetic epidemiology contribute to understanding environmental determinants of disease?

Associations between modifiable exposures and disease seen in observational epidemiology are sometimes confounded and thus misleading, despite our best efforts to improve the design and analysis of studies. Mendelian randomization-the random assortment of genes from parents to offspring that occurs during gamete formation and conception-provides one method for assessing the causal nature of some environmental exposures. The association between a disease and a polymorphism that mimics the biological link between a proposed exposure and disease is not generally susceptible to the reverse causation or confounding that may distort interpretations of conventional observational studies. Several examples where the phenotypic effects of polymorphisms are well documented provide encouraging evidence of the explanatory power of Mendelian randomization and are described. The limitations of the approach include confounding by polymorphisms in linkage disequilibrium with the polymorphism under study, that polymorphisms may have several phenotypic effects associated with disease, the lack of suitable polymorphisms for studying modifiable exposures of interest, and canalization-the buffering of the effects of genetic variation during development. Nevertheless, Mendelian randomization provides new opportunities to test causality and demonstrates how investment in the human genome project may contribute to understanding and preventing the adverse effects on human health of modifiable exposures.

Distinct Apolipoprotein E Isoform Preference for Inhibition of Smooth Muscle Cell Migration and Proliferation†

The current study compared the effectiveness of the various human apolipoprotein E (apoE) isoforms in inhibiting platelet-derived growth factor- (PDGF-) stimulated smooth muscle cell proliferation and migration. The incubation of primary mouse aortic smooth muscle cells with apoE3 resulted in dose-dependent inhibition of smooth muscle cells stimulated by 10 ng/mL PDGF. Greater than 50% inhibition of smooth muscle cell proliferation was observed at 15 microg/mL of human apoE3. Human apoE2 was less effective, requiring a higher concentration to achieve inhibition comparable to that of apoE3. Human apoE4 was the least effective of the apoE isoforms with no significant inhibition of cell proliferation observed at concentrations up to 15 microg/mL. Interestingly, apoE inhibition of PDGF-directed smooth muscle cell migration did not show preference for any apoE isoforms. Human apoE2, apoE3, and apoE4 were equally effective in inhibiting smooth muscle cell migration toward PDGF. These results are consistent with previous data showing that apoE inhibition of smooth muscle cell proliferation is mediated through its binding to heparan sulfate proteoglycans, whereas its inhibition of cell migration is mediated via binding to the low-density lipoprotein receptor related protein. The low efficiency of apoE4 to inhibit smooth muscle cell proliferation also suggested another mechanism to explain the association between the apolipoprotein epsilon4 allele with increased risk of coronary artery disease.

DNA-adducts and atherosclerosis: a study of accidental and sudden death males in the Czech Republic

Atherosclerosis and carcinogenesis may share some common mechanisms of the genotoxic action of exogenous compounds, such as polycyclic aromatic hydrocarbons (PAHs). The main objective of this study was to test the hypothesis that "bulky" aromatic DNA-adducts in smooth muscle cells (SMCs) of thoracic aortas taken at autopsy from sudden and accidental death male subjects, aged between 30 and 60 years (N=133), are associated with the stage of atherosclerosis. The subjects with severe atherosclerotic damage were treated as "Cases" (N=66). The subjects meeting diagnostic criteria for slight and moderate total atherosclerotic body damage were treated as "Controls" (N=67). An additional objective of the study was to evaluate the effect of known atherogenic risk factors and possible modifiers of atherosclerotic changes, such as age, smoking, plasma lipid and antioxidant vitamin levels and some genetic susceptibility markers, e.g. polymorphisms of GSTM1, GSTT1, NAT2, CYP1A1 or apolipoprotein E (APO E) genes. We found significantly higher DNA-adduct levels in "Cases" as compared with "Controls" (2.11+/-1.07 adducts/10(8) nucleotides versus 1.49+/-0.55 adducts/10(8) nucleotides, P<0.001). "Cases" were significantly older and had elevated heart weight and plasma cholesterol levels and a higher frequency of overweight subjects as compared with "Controls". No significant differences in DNA-adduct levels between smokers and non-smokers within either group were detected. Multivariate logistic regression revealed that the "bulky" aromatic DNA-adducts, which are the most likely related to environmental exposure to genotoxic chemicals, remain a statistically significant predictor of the stage of atherosclerosis (OR=3.76, 95% CI=1.54-9.18, P=0.004) even after adjustment for age, smoking, obesity, heart weight and genetic susceptibility markers (GSTT1 and CYP1A1-MspI polymorphisms) that were also significant predictors. The fact that the "bulky" aromatic DNA-adduct levels predict the progression of atherosclerosis independently of smoking indicates that the formation of atherosclerotic plaques may also be initiated by environmental exposures other than tobacco smoke.

Genes other than BRCA1 and BRCA2 involved in breast cancer susceptibility

This review focuses on genes other than the high penetrance genes BRCA1 and BRCA2 that are involved in breast cancer susceptibility. The goal of this review is the discovery of polymorphisms that are either associated with breast cancer or that are in strong linkage disequilibrium with breast cancer causing variants. An association with breast cancer at a 5% significance level was found for 13 polymorphisms in 10 genes described in more than one breast cancer study. Our data will help focus on the further analysis of genetic polymorphisms in populations of appropriate size, and especially on the combinations of such polymorphisms. This will facilitate determination of population attributable risks, understanding of gene-gene interactions, and improving estimates of genetic cancer risks.