Facteurs de risque du cancer du sein

Screening of BRCA1 (c.5177_5180delGAAA rs80357867 and c.4986+6T>C rs80358086) and the BRCA2 (c.6445_6446delAT rs80359592) Genes for Breast Cancer Prevention in Burkina Faso

Background

The objective of this study is to search for mutations in the BRCA1 (c.5177_5180delGAAA and c.4986+6T>C) and BRCA2 genes (c.6445_6446delAT) in a population of women diagnosed with breast cancer.

Methods

This is a case-control study that involved 140 participants, including 70 patients with histologically diagnosed breast cancer and 70 healthy women without breast cancer. Mutations in the BRCA1 (rs80357867, rs80358086) and BRCA2 (rs80359592) genes were tested by real-time PCR. The 95% confidence interval Odds Ratio (OR) was used to estimate the associations between specific genotypes and breast cancer.

Results

The study revealed that no mutations were detected for rs80359592. Similarly, no reference allele (TTTC/TTTC) of rs80357867 was found in this study. However, the homozygous double mutant (-/) genotype of this rs80357867 was observed in 11.43% and 1.43% of patients and controls respectively, while 88.57% of patients and 98.57% of controls had a heterozygous deletion (TTTC/-). Concerning rs80358086, 8.57% of the patients had a heterozygous mutation (A/G) with no significantly risk association with occurrence of breast cancer (OR = 6.46; 95% CI: 0.75-55.21; p = 0.11). In addition, this heterozygous mutation was significantly associated with a family history of breast cancer (OR=128; 95% CI: 9.46-1730.93) and breast cancer risk in nonmultiparous women (OR=6; 95% CI: 1-35.90; p= 0.05) but no association with overweight/obesity (OR=1.66; 95% CI: 0.18-15.35; p=1).

Conclusion

This study shows high frequencies of heterozygous mutation of rs80357867 and rs80358086 from patients. In Burkina Faso, these results could help with early diagnosis of breast cancer in patients.

A 23-gene prognostic classifier for prediction of recurrence and survival for Asian breast cancer patients

We report a 23- gene-classifier profiled from Asian women, with the primary purpose of assessing its clinical utility towards improved risk stratification for relapse for breast cancer patients from Asian cohorts within 10 years’ following mastectomy. Four hundred and twenty-two breast cancer patients underwent mastectomy and were used to train the classifier on a logistic regression model. A subset of 197 patients were chosen to be entered into the follow-up studies post mastectomy who were examined to determine the patterns of recurrence and survival analysis based on gene expression of the gene classifier, age at diagnosis, tumor stage and lymph node status, over a 5 and 10 years follow-up period. Metastasis to lymph node (N2-N3) with N0 as the reference (N2 vs. N0 hazard ratio: 2.02 (1.05–8.70), N3 vs. N0 hazard ratio: 4.32 (1.41–13.22) for 5 years) and gene expression of the 23-gene panel (P=0.06, 5 years and 0.02, 10 years, log-rank test) were found to have significant discriminatory effects on the risk of relapse (HR (95%CI):2.50 (0.95–6.50)). Furthermore, survival curves for subgroup analysis with N0-N1 and T1-T2 predicted patients with higher risk scores. The study provides robust evidence of the effectiveness of the 23-gene-classifier and could be used to determine the risk of relapse event (locoregional and distant recurrence) in Asian patients, leading to a meaningful reduction in chemotherapy recommendations.

Relationships between Exercise Modality and Activity Restriction, Quality of Life, and Hematopoietic Profile in Korean Breast Cancer Survivors

This study aimed to examine the relationships between activity restriction, quality of life (QoL), and hematopoietic profile in breast cancer survivors according to exercise modality. The subjects in this study were 187 female breast cancer survivors among a total of 32,631 participants in the Korea National Health and Nutrition Examination Survey, which was conducted from 2016 to 2018. The selected subjects participated in a questionnaire survey and blood analysis. A cross-analysis was conducted to determine the relationship between participation in various modality of exercise (e.g., aerobic exercise, resistance exercise, walking exercise). The phi coefficients or Cramer’s V value for activity restriction and QoL were calculated; an independent t-test was conducted to evaluate the differences between hematopoietic profiles based on the modality of exercise. Statistically significant correlations were seen between obesity and aerobic exercise and walking frequency, as well as between diabetes and aerobic exercise and activity restriction. With respect to QoL, there was a statistically significant correlation between participation in aerobic exercise and exercise ability, participation in aerobic exercise and anxiety/depression, participation in resistance exercise and subjective health status, participation in resistance exercise and exercise ability, and participation in weekly walking exercise and self-care ability. Regarding hemodynamic changes, red blood cells increased significantly in breast cancer survivors who participated in weekly resistance exercise compared to in those who did not. In conclusion, exercise participation had a positive effect on activity restriction, QoL, and hematopoietic profile in breast cancer survivors; in particular, some modalities of aerobic exercise were more effective.

Association of APC and MCC Polymorphisms with Increased Breast Cancer Risk in an Indian Population

The adenomatous polyposis coli (APC) and mutated in colorectal cancer (MCC) genes are key regulatory genes of the Wnt/β-catenin signaling pathway, which are independently involved in maintaining low levels of β-catenin in the cell. In addition to genetic and epigenetic alterations, some genetic polymorphisms in the genes associated with the Wnt signaling pathway have been reported to be associated with an increased risk of cancer, including breast cancer. In the present study we analyzed the association of genotype and haplotype status of two single nucleotide polymorphisms (SNPs), rs2229992 and rs11283943, in the APC and MCC genes, respectively, with an increased risk of breast carcinogenesis in a breast cancer and control population from eastern India. We observed a significant association of the rs11283943 SNP with increased breast cancer risk. Two specific haplotypes involving the minor allele of rs11283943 were found to be associated with an increased breast cancer risk. Kaplan-Meier curves showed a significant association of the 2–2 genotype (genotype homozygous for the rs11283943 minor allele) with decreased survival (p=0.045) of the breast cancer patients in our study, in particular patients with early-onset BC.

No evidence of excessive cancer screening in female noncarriers from BRCA1/2 mutation-positive families

BACKGROUND

In families with a proven BRCA1/2 mutation, women not carrying the familial mutation should follow the cancer screening recommendations applying to women in the general population. In the present study, we evaluated the cancer screening practices of unaffected noncarriers from families with a proven BRCA mutation, and we assessed the role of family history in their screening practices.

METHODS

Self-report data were provided retrospectively by 220 unaffected female noncarriers for periods of up to 10 years (mean: 4.3 years) since disclosure of their BRCA1/2 genetic test result. A ratio for the annual frequency of breast and ovarian cancer screening exams (mammography, breast ultrasonography, breast magnetic resonance imaging, transvaginal or pelvic ultrasound, cancer antigen 125 testing) was calculated as number of screening exams divided by the number of years in the individual observation period.

RESULTS

The annual average for mammography exams was 0.15, 0.4, 0.56, and 0.71 in women 30-39, 40-49, 50-59, and 60-69 years of age respectively. The uptake of other breast and ovarian cancer screening exams was very low. Mammography and breast ultrasonography and magnetic resonance imaging were generally more frequent among participants with at least 1 first-degree relative affected by breast cancer.

CONCLUSIONS

In most noncarriers, screening practices are consistent with the guidelines concerning women in the general population. When noncarriers adopt screening behaviours that are different from those that would be expected for average-risk women, those behaviours are influenced by their familial cancer history.

IMPACT

Decision tools might help female noncarriers to be involved in their follow-up in accordance with their genetic status and their family history, while taking into account the benefits and disadvantages of cancer screening.

Adipokines in hereditary breast cancer patients and healthy relatives

Background

The role of adipocytokines and ghrelin in hereditary breast cancer syndrome (HBCS) has never been tested.

Results

No significant differences in leptin, adiponectin and ghrelin plasma levels between cancer patients and healthy subjects was observed. Conversely, an higher level of adiponectin was shown in healthy subjects with BRCA 1/2 gene mutation vs those without (p < 0.03). Logistic regression analysis demonstrated that Adiponectin plasma level (OR 0.26; 95% CI:0.007–0.81; p < 0.02) and age (OR 5.51; 95% CI:1.78–19.71; p < 0.004) were the only factors independently associated with BMI; furthermore, Leptin plasma level (OR 0.23; 95% CI:0.06–0.76; p < 0.01) and age (OR 0.05; 95% CI:0.05–0.61; p < 0.007) resulted the only factors significantly associated with breast cancer.

Materials and Methods

We analyzed blood plasma expression of leptin, adiponectin and ghrelin using Bio-Plex platform in 25 breast cancer patients with HBCS and in 38 healthy relatives. BRCA 1/2 gene status (presence of pathogenic mutations by direct molecular sequencing), clinical-pathological characteristics and Body Mass Index (BMI) of each subject were recorded.

Conclusions

Adiponectin confirms to be associated with BMI also in subjects with HBCS. Leptin plasma level seems a direct and independent biomarker of a breast cancer risk. A validation of Leptin as a circulating biomarker of breast cancer development in larger series of HBCS subjects is needed.

Frequent alterations of homologous recombination repair pathway in primary and chemotolerant breast carcinomas: clinical importance

Aim: To understand the importance of homologous recombination repair pathway in development of breast carcinoma (BC), alterations of some key regulatory genes like BRCA1, BRCA2, FANCC and FANCD2 were analyzed in pretherapeutic/neoadjuvant chemotherapy (NACT)-treated BC samples. Materials & methods: Alterations (deletion/methylation/expression) of the genes were analyzed in 118 pretherapeutic and 41 NACT-treated BC samples. Results: High deletion/methylation (29–68%) and 64–78% overall alterations of the genes were found in the samples. Concordance was evident between alteration and protein expression of the genes. Estrogen/progesterone receptor-negative tumors showed significantly high alterations even in NACT-treated samples having low CD44 and proliferating cell nuclear antigen expression. Pretherapeutic patients with alterations showed poor prognosis. Conclusion: Alterations of homologous recombination repair pathway genes are needed for the development of BC.

Multiparity and Breast Cancer Risk Factor among Women in Burkina Faso

The relative lack of information on breast cancer etiology in Burkina Faso led us to undertake the present work to highlight risk factors. This prospective study was conducted using a questionnaire between January 2015 and February 2016 on women admitted to Yalgado OUEDRAOGO hospital, for consultation or supervision. The characteristics of multiparous breast cancer patients (n = 44) were compared with their non-multiparous counterparts (n = 36). The study found that increased risk of breast cancer among non-multiparous cases was related to body mass index (BMI) (p <0.001), age at menopause (p <0.004) and use of oral contraception (p <0.021) while abortion (p <0.002) was a risk factor among multiparous cases. These results suggest that even if multiparity is associated with a decreased risk in some women, avoidance of abortion during reproductive life should be recommended. The results provide preliminary information, which now need to be supplemented by survey of a larger sample in the national territory.

[Eco-epidemiology: towards epidemiology of complexity]

In order to solve public health problems posed by the epidemiology of risk factors centered on the individual and neglecting the causal processes linking the risk factors with the health outcomes, Mervyn Susser proposed a multilevel epidemiology called eco-epidemiology, addressing the interdependence of individuals and their connection with molecular, individual, societal, environmental levels of organization participating in the causal disease processes. The aim of this epidemiology is to integrate more than a level of organization in design, analysis and interpretation of health problems. After presenting the main criticisms of risk-factor epidemiology focused on the individual, we will try to show how eco-epidemiology and its development could help to understand the need for a broader and integrative epidemiology, in which studies designed to identify risk factors would be balanced by studies designed to answer other questions equally vital to public health.

General Practitioners and Breast Surgeons in France, Germany, Netherlands and the UK show variable breast cancer risk communication profiles

BACKGROUND

No information is available on the attitudes of General Practitioners (GPs) and Breast Surgeons (BSs) to their delivery of genetic, environmental and lifestyle risk factor information about breast cancer. The aim of this study was to describe the Breast Cancer Risk Communication Behaviours (RCBs) reported by GPs and BSs in four European countries and to determine the relationships between their RCBs and their socio-occupational characteristics.

METHODS

Self-administered questionnaires assessing breast cancer risk communication behaviours using vignettes were mailed to a sample of Breast Surgeons (BS) and General Practitioners (GP) working in France, Germany, the Netherlands, and the UK (N = 7292). Their responses to questions about the risk factors were first ordered and compared by specialty and country after making multivariate adjustments. Rather than defining a standard Risk Presentation Format (RPF) a priori, the various RPFs used by the respondents were analyzed using cluster analysis.

RESULTS

Family history and hormonal replacement therapy were the risk factors most frequently mentioned by the 2094 respondents included in this study. Lifestyle BC risk factors such as obesity and alcohol were rarely/occasionally mentioned, but this point differed (p < 0.001) depending on the country and the specialty of the providers involved. Five distinct RPF profiles including the numerical/verbal presentation of absolute/relative risks were identified. The most frequently encountered RPF (34.2%) was characterized by the fact that it included no negative framing of the risks, i.e., the probability of not developing cancer was not mentioned. Age, specialty and country of practice were all found to be significant determinants of the RPF clusters.

CONCLUSIONS

The increasing trend for GPs and BSs to discuss lifestyle risk factors with their patients suggests that this may be a relevant means of improving breast cancer prevention. Physicians' risk communication skills should be improved during their initial and vocational training.

Subtype-specific alterations of the Wnt signaling pathway in breast cancer: clinical and prognostic significance

The aim of the study is to understand the importance of the Wnt/β-catenin pathway in the development of breast cancer (BC) and its association with different clinicopathological parameters. Alterations (deletion/methylation/expression) of some Wnt/β-catenin pathway antagonists like APC, SFRP1/2, CDH1 and activator β-catenin (CTNNB1) were analyzed in primary BC in Indian patients. High frequencies (65-70%) of overall alterations (deletion/methylation) of the antagonists were seen in the BC samples. Also, 99% (156/158) of the samples showed alterations in any one of the genes, indicating the importance of this pathway in the development of this tumor. Co-alterations of these genes were observed in 30% of samples, with significantly high alterations in late-onset (37%) and estrogen receptor (ER)-/progesterone receptor (PR)- (37%) BC compared with early onset (21%) and ER/PR+ (18%) BC samples, respectively. Significantly high (P-value = 0.001-0.02) alterations of APC and CDH1 genes were seen in ER-/PR- BC compared with ER/PR+ BC. Immunohistochemical analysis showed reduced expression of the Wnt antagonists in BC concordant with their molecular alterations. Nuclear localization of β-catenin showed significant association with alterations in the antagonists and was also significantly high in the ER-/PR- BC samples. Alterations of SFRP2 coupled with a late clinical stage and low/nulliparity predicted the worst prognosis in BC patients. Therefore, the present study suggests that cumulative alterations in more than one Wnt antagonist along with increased nuclear accumulation of β-catenin play an important role in the development of BC and have significant clinical as well as prognostic importance.

[Representations and attitudes toward cancer in the French general population]

Cancer has become a major public health issue. It is thus crucial to measure the general population's behaviours, opinions and perceptions about cancer and its associated risk factors. This article describes some of the main findings of a 2005 French survey (n = 4,046). Cancer is considered by a large majority to be the most serious disease, far before HIV/AIDS and cardiovascular diseases. The carcinogenic risk that is associated to main risk factors, such as sun exposure, tobacco-smoking and alcohol use appears to be well-known. However, many people justify dangerous behaviours with strongly-anchored beliefs, which maintain dangerous behaviours for health on the long-term. What's more, the perception of risk proliferation can also generate risk denial. Because self-exempting beliefs are still widespread within the general opinion, it is essential to continue public health information campaigns dedicated to cancer prevention, so as to induce better prevention practices within the general population and to reduce stigmatisation and isolation experienced by cancer patients. If risk denial is not systematically a consequence of a lack of information, it is generally associated to a cognitive construction that gives coherence to behaviours.

Relation between insulin resistance and breast cancer among Chilean women

PURPOSE

In Chile, diabetes and breast cancer are important public health problems. The association between insulin resistance and breast cancer, however, remains largely unexplored.

METHODS

We conducted a case-control study to assess the relationship of insulin resistance (IR) and breast cancer in Chilean premenopausal and postmenopausal women. We compared 170 women, 33 to 86 years old, with incident breast cancer and 170 normal mammography controls, matched by 5-year age interval. Plasmatic insulin and glucose were measured and IR was calculated by the homeostasis model assessment method. Anthropometric measurements and sociodemographic and behavioral data were also collected. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by multivariable conditional logistic regression.

RESULTS

IR was independently associated with breast cancer in postmenopausal women (OR = 2.70, 95%CI = 1.10-6.63), but not in premenopausal women (OR = 0.84, 95%CI = 0.20-3.52). Obesity was not associated with breast cancer at any age (OR = 0.68, 95%CI = 0.39-1.20).

CONCLUSION

In this sample, IR increased the risk of breast cancer among postmenopausal women.

(Anti)estrogenic effects of phytochemicals on human primary mammary fibroblasts, MCF-7 cells and their co-culture

In the public opinion, phytochemicals (PCs) present in the human diet are often considered beneficial (e.g. by preventing breast cancer). Two possible mechanisms that could modulate tumor growth are via interaction with the estrogen receptor (ER) and inhibition of aromatase (CYP19). Multiple in vitro studies confirmed that these compounds act estrogenic, thus potentially induce tumor growth, as well as aromatase inhibitory, thus potentially reduce tumor growth. It is thought that in the in vivo situation breast epithelial (tumor) cells communicate with surrounding connective tissue by means of cytokines, prostaglandins and estradiol forming a complex feedback mechanism. Recently our laboratory developed an in vitro co-culture model of healthy mammary fibroblasts and MCF-7 cells that (at least partly) simulated this feedback mechanism (M. Heneweer et al., TAAP vol. 202(1): 50-58, 2005). In the present study biochanin A, chrysin, naringenin, apigenin, genistein and quercetin were studied for their estrogenic properties (cell proliferation, pS2 mRNA) and aromatase inhibition in MCF-7 breast tumor cells, healthy mammary fibroblasts and their co-culture. The proliferative potency of these compounds in the MCF-7 cells derived from their EC(50)s decreased in the following order: estadiol (4*10(-3) nM)>biochanin A (9 nM)>genistein (32 nM)>testosterone (46 nM)>naringenin (287 nM)>apigenin (440 nM)>chrysin (4 microM). The potency to inhibit aromatase derived from their IC(50)s decreased in the following order: chrysin (1.5 microM)>naringenin (2.2 microM)>genistein (3.6 microM)>apigenin (4.1 microM)>biochanin A (25 microM)>quercetin (30 microM). The results of these studies show that these PCs can induce cell proliferation or inhibit aromatase in the same concentration range (1-10 microM). Results from co-cultures did not elucidate the dominant effect of these compounds. MCF-7 cell proliferation occurs at concentrations that are not uncommon in blood of individuals using food supplements. Results also indicate that estrogenicity of these PCs is quantitatively more sensitive than aromatase inhibition. It is suggested that perhaps a more cautionary approach should be taken for these PCs before taken as food supplements.