Association between single-nucleotide polymorphisms in miRNA and breast cancer risk: an updated review

Breast cancer (BC), a heterogeneous, aggressive illness with high mortality, is essentially a genomic disease. While the high-penetrance genes BRCA1 and BRCA2 play important roles in tumorigenesis, moderate- and low-penetrance genes are also involved. Single-nucleotide polymorphisms (SNPs) in microRNA (miRNA) genes have recently been identified as BC risk factors. miRNA genes are currently classified as low-penetrance. SNPs are the most common variations in the human genome. While the role of miRNA SNPs in BC susceptibility has been studied extensively, results have been inconsistent. This review analyzes the results of association studies between miRNA SNPs and BC risk from countries around the world. We conclude that: (a) By continent, the largest proportion of studies to date were conducted in Asia (65.0 %) and the smallest proportion in Africa (1.8 %); (b) Association studies have been completed for 67 different SNPs; (c) 146a, 196a2, 499, 27a, and 423 are the most-studied miRNAs; (d) The SNPs rs2910164 (miRNA-146a), rs11614913 (miRNA-196a2), rs3746444 (miRNA-499) and rs6505162 (miRNA-423) were the most widely associated with increased BC risk; (e) The majority of studies had small samples, which may affect the precision and power of the results; and (f) The effect of an SNP on BC risk depends on the ethnicity of the population. This review also discusses potential explanations for controversial findings.

Nivel de conocimiento sobre los factores de riesgo y las medidas preventivas del cáncer de mama en estudiantes de ciencias de la salud / estudiantes de ciencias de la salud Level Of Knowledge On Risk Factors And Preventive Measures For Breast Cancer In Health Science Students

Introducción: El cáncer de mama es uno de los cánceres más comunes a nivel mundial y en el Perú, por ello es importante que los estudiantes en salud conozcan las medidas preventivas y factores de riesgo. Objetivo: Evaluar el nivel de conocimiento sobre los factores de riesgo y medidas de prevención para el cáncer de mama en estudiantes de la escuela de medicina de una universidad privada, 2019. Métodos: Estudio cuantitativo, descriptivo de corte transversal, se contó con una muestra de 319 estudiantes de la Facultad de Medicina de la Universidad Católica Santo Toribio de Mogrovejo en el año 2019,que hayan estado matriculados en alguna de las escuelas profesionales. Se utilizó un cuestionario que constó de 18 preguntas, 5 ítems que abordaron datos sociodemográficos y 13 midieron el nivel de conocimiento sobre los factores de riesgo y medidas de preventivas del cáncer de mama. Se usó estadística descriptiva. Resultados: Después de la exclusión, se contó con 292 estudiantes, 72% fueron mujeres. La media de edad fue 20,5. 23,6 % fueron de segundo ciclo. Los factores de riesgo menos conocidos fueron beber alcohol, tener más de 45 años, menarquia antes de los 12 años y menopausia después de los 55 años, asimismo, las medidas de prevención menos conocidas fueron: edad correcta para realizar mamografía 71% y frecuencia para realizar autoexamen 63% en mayor porcentaje. Conclusión: El conocimiento sobre factores de riesgo y medidas de prevención de cáncer de mama fue adecuado.

Introduction: breast cancer is one of the most common cancers worldwide and in Peru. Health studentsneed to know preventive measures and risk factors. Objective: to assess the level of knowledge aboutrisk factors and prevention measures for breast cancer in students of the private medical school, 2019.Methods: a quantitative, descriptive cross-sectional study was conducted with a sample of 319 studentsfrom the Faculty of Medicine of the Universidad Católica Santo Toribio de Mogrovejo in 2019, who havebeen enrolled in one of the professional schools. We used a questionnaire consisting of 18 questions, 5items that addressed sociodemographic data, and 13 measured the level of knowledge about risk factorsand preventive measures of breast cancer. Descriptive statistics were used. Results: After exclusion,there were 292 students, 72% were women. The mean age was 20.5, 23.6% were from the second year.The least known risk factors were drinking alcohol, being over 45 years of age, menarche before 12years of age, and menopause after 55 years of age, and the least known prevention measures were:correct age for mammography 71% and frequency for self-examination 63% in a higher percentage.Conclusion: knowledge about risk factors and breast cancer prevention measures was adequate.

Human Epidermal Growth Factor Receptor-2 gene polymorphism and breast cancer risk in women from the Northeastern region of Brazil

OBJECTIVES: In the Human Epidermal Growth Factor Receptor-2 (HER2) rs1136201 variant, the presence of the G allele may promote cellular alterations and increase breast cancer risk, in addition to enhanced cellular proliferation, tumor aggressiveness, and metastases. The aim of this study was to investigate the presence of the single-nucleotide polymorphism (SNP) variant, rs1136201, within the HER2 gene in women from the Northeastern region of Brazil and breast cancer risk. METHODS: The study included 140 women who were divided into two groups, case (breast cancer) and control (without breast cancer), with 70 women in each group. Peripheral blood of each woman was drawn for the study of genomic Deoxyribonucleic acid (DNA) extracted from leukocytes using the genotyping technique by real-time polymerase chain reaction. RESULTS: The GG genotype occurred in 1 woman in both groups (1.4%) (p=0.32), while the AG genotype occurred in 19 (27.2%) and 13 (18.6%) women in the case and control (p=1.00) groups, respectively. No statistically significant difference in GG and AG genotypes was observed between the case and control groups in premenopausal women (p=1.00). Furthermore, no significant difference in genotypes was observed between the groups, among postmenopausal women (p=0.14). CONCLUSION: In this study, the HER2 rs1136201 polymorphism did not show any statistically significant association with breast cancer, both in premenopausal and postmenopausal women. Nevertheless, further studies with a larger sample size should be performed to assess the association of HER2 polymorphism with breast cancer risk in women from the Northeastern region of Brazil.

RELATIONSHIP BETWEEN OBESITY AND BREAST CANCER / Relação entre obesidade e câncer de mama

Obesity is a growing clinical condition around the world, considered a risk factor for numerous diseases such as hypertension, myocardial infarction, diabetes, and cancer. Among the neoplasms related to overweight, breast cancer stands out. Therefore, the objective of this review is to elucidate the impact of obesity on the most prevalent cancer among women, either as a direct risk factor for its onset or as a determinant of survival

A obesidade aponta como condição clínica em ascensão pelo mundo, considerada fator de risco para inúmeras doenças como hipertensão, infarto, diabetes e câncer. Dentre as neoplasias relacionadas com o excesso de peso, destaca-se o câncer de mama. O objetivo desta revisão é, portanto, elucidar o impacto que a obesidade causa no câncer mais prevalente entre as mulheres, seja como fator de risco direto para seu aparecimento, seja como determinante na sobrevida

Riesgo familiar total en familias con mujeres diagnosticadas con neoplasia de mama / Total family risk in families with women diagnosed with breast cancer / Risco familiar total em famílias com mulheres diagnosticadas com neoplasia da mama

Objetivo: Determinar el riesgo familiar total de las familias con mujeres diagnosticadas con cáncer de mama, que asisten a un centro de salud oncológico en la ciudad de Barranquilla. Materiales y Métodos: El estudio fue de tipo descriptivo, transversal con abordaje cuantitativo. Se utilizó el instrumento Riesgo Familiar Total RFT 5-33. El universo estuvo conformado por familias con mujeres diagnosticadas con cáncer en mama. La muestra fue de 41 familias que integraron a 154 miembros; se abordó el estudio de manera censal, y no por medio de una muestra, porque el acceso a la información de la totalidad de las familia fue viable. Resultados: Los resultados mostraron que las familias, en su mayoría, son de tipo 2. El 68 % de las pacientes categorizan sus familias como amenazadas, el 5 % como familias de alto riesgo y un 27 % de las familias con un bajo riesgo. Conclusiones: Los hallazgos encontrados en esta investigación son importantes para las familias, lo cual permitirá establecer acciones y actividades que logren orientar e implementar procesos de atención específicos con el propósito de cuidar a las familias para que se mantengan sanos en un nivel de bajo riesgo; además, desarrollar controles y seguimiento a aquellas familias que se encuentran en un riesgo alto de amenazas, mediante acciones de promoción y prevención de la enfermedad de una manera amplia. Por lo anterior, se deben emprender programas más agresivos de prevención y promoción, especialmente con las familias que asisten en busca de apoyo médico para este padecimiento; de esta forma, se podrán diagnosticar los casos de forma temprana y proceder al respectivo tratamiento.

Objective: To determine the total family risk with women diagnosed with breast cancer, that attend an oncological health center in the city of Barranquilla. Materials and Methods: The study was descriptive, cross-sectional with a quantitative approach. The instrument of Total Family Risk RFT 5-33 was used. The universe was composed by families with women diagnosed with breast cancer. The sample were 41 families integrated by 154 members; the study was approached as a census, and not through samples, because the access to the information in its entirety was viable. Results: The results showed that the families, in their majority are from type 2. 68% of the patients categorize their families as threatened, 5% as families of high risk, and 27% of the families as low risk. Conclusion: The data found in this research, is important for the families, which will allow to establish actions and activities to orientate and implement processes of specific attention, with the purpose of taking care of the families in order to keep them healthy and in a level of low risk; also, to develop controls and monitoring, to those families that have a high risk of threat through actions of promotion and prevention of the disease in a broad manner. Consequently, more aggressive programs of prevention and promotion must begin, especially with the families that attend in search of medical support for this condition; this way breast cancer cases can be diagnosed early and proceed to the proper treatment.

Objetivo: Determinar o risco familiar total das famílias com mulheres diagnosticadas com câncer de mama, que assistem a um centro de saúde oncológica na cidade de Barranquilla - Colômbia. Materiais e Métodos: O estudo foi de tipo descritivo, transversal com abordagem quantitativa. Utilizou-se o instrumento Risco Familiar Total RFT 5-33. O universo esteve conformado por famílias com mulheres diagnosticadas com câncer de mama. A amostra foi de 41 famílias que integraram a 154 membros; se abordou o estudo utilizando um censo, e não por meio de uma amostra, porque o acesso à informação de todas as famílias foi viável. Resultados: Os resultados mostraram que as famílias em sua maioria são de tipo 2. O 68% das pacientes categorizam suas famílias como ameaçadas, o 5% como famílias de alto risco, e um 27% das famílias com um baixo risco. Conclusões: Os resultados encontrados nesta pesquisa, são importantes para as famílias, já que podem-se estabelecer ações e atividades que logrem orientar e implementar processos de atendimento específicos, com o propósito de cuidar às famílias para que se mantenham saudáveis num nível de baixo risco; assim como também desenvolver controles e seguimentos, sobretudo a aquelas famílias que se encontram num risco alto de ameaças, através de ações de promoção e prevenção da doença de uma maneira ampla. Portanto, se devem empreender programas mais agressivos de prevenção e promoção, especialmente com as famílias que assistem em procura de apoio médico para este padecimento; e desta maneira conseguir diagnosticar os casos de forma precoce e proceder ao respectivo tratamento.

Prevalence of the STK15 F31I polymorphism and its relationship with mammographic density

Several studies have identified the single nucleotide polymorphism STK15 F31I as a low-penetrance risk allele for breast cancer, but its prevalence and risk association in the Brazilian population have not been determined. The goal of this study was to identify the frequency of this polymorphism in the Brazilian setting. Considering the high degree of admixture of our population, it is of fundamental importance to validate the results already reported in the literature and also to verify the relationship between this variant and breast cancer risk. A total of 750 women without breast cancer were genotyped using the TaqMan PCR assay for STK15 F31I polymorphism. Clinical information was obtained from review of the medical records and mammographic density from the images obtained using the BI-RADS System. The estimated risk of developing cancer was calculated according to the Gail model. The genotypic frequencies observed in this study were 4.5, 38.7, and 56.6 percent, respectively, for the STK15 F31I AA, AT and TT genotypes. The AT and AA genotypes were encountered significantly more often in premenopausal women with moderately dense, dense and heterogeneously dense breast tissue (P = 0.023). In addition, the presence of the TT genotype was significantly associated with age at menarche ≥12 years (P = 0.023). High mammographic density, associated with increased breast cancer risk, was encountered more frequently in premenopausal women with the risk genotypes STK15 F31I AA and AT. The genotypic frequencies observed in our Brazilian sample were similar to those described in other predominantly European populations.

Conocimientos y comportamientos sobre factores de riesgo de cáncer de mama en un grupo de mujeres / Knowledge and behaviors on breast cancer risk factors among a group of women

Introducción: En México cada 2 horas muere una mujer por cáncer de mama (CaMa), enfermería debe asumir un rol protagónico en promover la salud de la mama. Objetivo: Explorar la relación que existe entre conocimientos y comportamientos sobre factores de riesgo y detección oportuna del cáncer de mama en un grupo de mujeres. Material y métodos: Estudio piloto observacional, descriptivo y transversal, incluyó 52 mujeres mayores de 25 años de una institución educativa. Las variables fueron: factores de riesgo para CaMa, antecedentes personales, conductas protectoras o de riesgo, conocimientos y screening, Resultados: con una K Richardson 0.73. La media de edad 38±8, las mujeres de 47-57 años tienen menor nivel de escolaridad (Z= - 2.87, p=0.004), y menos conocimientos (Anova p=0.02). Las mujeres que no reportaron datos de enfermedad crónica tienen un promedio mayor de conductas de riesgo (3±1) que aquellas que si lo presentan (2±1, t= 2.944, gl=50, p < 0.005). Discusión: Los resultados concuerdan con lo reportado en la literatura, los conocimientos son deficientes y no se relacionan con conductas saludables ni garantizan que las mujeres realicen detección oportuna. Conclusiones:En el espacio universitario se deben implementar estrategias que incrementen los conocimientos y la detección oportuna de CaMa.

Introduction: In Mexico, every two hours a woman dies of breast cancer (BrCa); thus Nursing should assume a principal roll in the promotion of women's health. Objective: explore the relationship between knowledge and behavior related to risk factors and BrCa early detection. Materials and methods: basic, descriptive, and observational study pilot, which included 52 women older than 25 working in an education institution. The variables were BrCa risk factors, personal background, protecting or risk conducts, knowledge and screening. Results: K Richardson was .73. Average age was 38 +- 8. Women between 47-57 reported a lower level of education (Z = -2.87, p = .004), and less knowledge (ANOVA p = .02). Women who did not report chronic illness data reported greater average number of risk conducts (3+-1) than those who did (2+-1, t = 2.944, gl = 50, p < .005). Discussion: our results are consistent with those of the literature: when knowledge is insufficient women do not behave healthy and do not perform early detection practices. Conclusion: it is necessary to implement strategies to enhance knowledge and frequency of BrCa early detection practices.

Risk factors of breast cancer in Asian women: a Meta-analysis / 中华流行病学杂志

Objective To evaluate the risk factors of breast cancer in Asian women and to provide evidences for establishing a risk assessment model. Methods Published studies concerning risk factors of breast cancer in Asian women were searched systemically and assessed by NOS (Newcastle-Ottawa Scale) items between 1995 and 2010. RevMan 4.2 software was used for data analysis and for calculating OR and its 95%CI on every risk factor. Results 27 studies including 403170 women were selected for Meta-analysis. According to NOS items, 20 studies were classified as A degree and 7 studies were evaluated as B degree. The risk factors of breast cancer and its pooled odds ratio values with statistical significance were as follows: 3.00 (95%CI: 1.68-5.36) when number of abortions≥3; 2.39 (95%CI: 1.78-3.21 ) when with family history of breast cancer; 1.54(95%CI: 1.30-1.82) when age at first live birth ≥30 (year); smoking was 1.50(95%CI: 1.03-2.20); 1.48(95%CI:1.20-1.83) with no live births; 1.29 (95%CI: 1.12-1.47) with no breast feeding; 1.26 (1.07-1.49)with age at menarche ≤12 (year) and 1.16(95%CI: 1.01-1.32) with alcohol drinking. Conclusion Number of abortions≥3, family history of breast cancer, age at first live birth ≥30 (year) ,smoking, no live births, no breast feeding, age at menarche ≤ 12 (year), and alcohol drinking were among the priorities in the establishment of breast cancer risk assessment model for Asian women.

Actividad física y riesgo de cáncer de mama en mujeres mexicanas / Physical activity and breast cancer risk in Mexican women

OBJETIVO: Evaluar el efecto de la actividad física moderada (en horas por semana y METs-hora por semana) sobre el riesgo de cáncer de mama (CM). MATERIAL Y MÉTODOS: Se trata de la primera fase de un estudio multicéntrico de casos y controles con base poblacional que se desarrolló en el Distrito Federal, Monterrey y Veracruz, México, en el año 2004. Se analizaron 58 casos y 58 controles pareados a los casos por quinquenio de edad, y pertenencia al sistema de salud; participaron tres hospitales del Instituto Mexicano del Seguro Social, tres del Instituto de Seguridad Social al Servicio de los Trabajadores del Estado y tres de la Secretaría de Salud. RESULTADOS: En mujeres posmenopáusicas se observó una reducción del riesgo de CM por cada hora semanal adicional de actividad física moderada (RM= 0.91; IC95 por ciento 0.85-0.97); en mujeres premenopáusicas, la disminución del riesgo no tuvo significancia estadística (RM= 0.99; IC95 por ciento 0.94-1.05) (p= 0.048, modificación de efecto). CONCLUSIONES: La actividad física reduce el riesgo de CM en mujeres mexicanas posmenopáusicas.

OBJECTIVE: To evaluate the effect of moderate physical activity (hours per week and METs hours per week) on the risk of breast cancer (BC) in Mexican women. MATERIAL AND METHODS: This is the initial stage of a case control multicentric study based in the Federal District, Monterrey and Veracruz, Mexico, during 2004. Fifty eight cases paired to 58 control cases on quinquennium of age, and belonging to the health system were analyzed: three hospitals from the IMSS, three from ISSSTE and three from SS participated. RESULTS: In postmenopausal women, there was a reduction of the risk in BC by every additional hour per week of moderate physical activity (RM= 0.91; IC95 percent 0.85-0.97); in premenopausal women, the reduction of the risk was not statistically significant (RM= 0.99; IC95 percent 0.94-1.05) (p= 0.048, effect modification). CONCLUSIONS: Moderate physical activity reduces the risk of BC in postmenopausal Mexican women.

Reproductive Factor and Food Intake Pattern Influencing on the Breast Cancer Risk in Daegu Gyungbuk Area, Korea

The present study examined the reproductive factors and food intake pattern which influence on the breast cancer risk in Daegu Gyungbuk area. The case subjects were 103 patients newly diagnosed as breast cancer at Kyungpook National University Hospital. The control subjects were 159 healthy women selected by frequency matching of age and menopausal status in the same community. The survey was conducted by individual interviews using questionnaires which include general and reproductive characteristics, dietary habits, and food frequency. The odds ratios were calculated by using unconditional logistic regression after adjusting for confounding variables. The mean age of the subjects was 50 yrs, and mean body mass index was significantly high in the patient group than in the control. The patient group had a significantly higher familial history of breast cancer and a significantly shorter breast-feeding period compared to the control group. It has been found no significant relationship between extrinsic hormone use such as oral contraceptives or estrogen replacement therapy and breast cancer risk. In regard of food habits, a high preference for the cooking method of steaming rather than frying, panbroiling or roasting was significantly associated with lower relative risk of breast cancer. The higher intake frequencies of fruits for all subjects, and seaweeds only for postmenopausal subjects were related with a significantly lower relative risk of breast cancer. The results of the study suggest that the possible risk factors for the breast cancer occurrence include high BMI, family history, less breast feeding experience, preference for the cooking method of frying, and less consumption of fruits and seaweeds. This study provides an useful data for nutrition education to prevent breast cancer for the residents in Daegu Gyungbuk area.