Clinical characterization and risk profile of individuals seeking genetic counseling for hereditary breast cancer in Brazil

Systematic review of the molecular basis of hereditary breast and ovarian cancer syndrome in Brazil: the current scenario

BACKGROUND

A detailed understanding of the genetic basis of cancer is of great interest to public health monitoring programs. Although many studies have been conducted in Brazil, a global view on the molecular profile related to hereditary breast and ovarian cancer (HBOC) in this large and heterogeneous population is lacking.

METHODS

A systematic review following the PRISMA guidelines was conducted in three electronic databases (PubMed, BIREME and SciELO). Brazilian studies covering molecular analysis of genes related to HBOC, published until December 2023, were considered.

RESULTS

We identified 35 original studies that met all the inclusion criteria. A total of 137 distinct mutations were found in the BRCA1 gene, but four of them corresponded to 44.5% of all mutations found in this gene. The c.5266dupC BRCA1 mutation was responsible for 26.8% of all pathogenic mutations found in the BRCA1 gene in patients with clinical criteria for HBOC from the Brazilian population. Considering all studies that track this mutation in the BRCA1 gene, we found a frequency of 2% (120/6008) for this mutation in Brazilian patients. In the BRCA2 gene, the four most frequent mutations corresponded to 29.2% of pathogenic mutations. Even though it was tracked by few studies, the c.156_157insAlu mutation was responsible for 9.6% of all pathogenic mutations reported in the BRCA2 gene. Seventeen studies found pathogenic mutations in other non-BRCA genes, the c.1010G > A mutation in the TP53 gene being the most frequent one. Considering all studies that screened for this specific mutation in patients with the clinical criteria for HBOC, the frequency of c.1010G > A was estimated at 1.83% (61/3336).

CONCLUSIONS

Despite significant molecular heterogeneity among mutations in HBOC patients from Brazil, three mutations deserve to be highlighted, c.5266dupC, c.156_157insAlu and c.1010G > A in the BRCA1, BRCA2 and TP53 genes, respectively. With more than 200 records, these three mutations play a vital role in the pathology of breast and ovarian cancer in Brazil. The data collected shed light on the subject, but there is still not enough data from certain subpopulations.

Inequities in genetic testing for hereditary breast cancer: implications for public health practice

The Ontario Breast Screening Program for women with a genetic predisposition to breast cancer is one of the first international models of a government-funded public health service that offers systematic genetic screening to women at a high risk of breast cancer. However, since the implementation of the program in 2011, enrolment rates have been lower than anticipated. Whilst there may be several reasons for this to happen, it does call into consideration the 'inverse equity law', whereby the more advantaged in society are the first to participate and benefit from universal health services. An outcome of this phenomenon is an increase in the health divide between those that are at a social advantage versus those that are not. Using an intersectionality lens, this paper explores the role of the social determinants of health and social identity in creating possible barriers in the access to genetic screening for hereditary breast cancer, and the implications for public health practice in recognising and ameliorating these differences.

Prevalence of BRCA1/BRCA2 mutations in a Brazilian population sample at-risk for hereditary breast cancer and characterization of its genetic ancestry

Background

There are very few data about the mutational profile of families at-risk for hereditary breast and ovarian cancer (HBOC) from Latin America (LA) and especially from Brazil, the largest and most populated country in LA.

Results

Of the 349 probands analyzed, 21.5% were BRCA1/BRCA2 mutated, 65.3% at BRCA1 and 34.7% at BRCA2 gene. The mutation c.5266dupC (former 5382insC) was the most frequent alteration, representing 36.7% of the BRCA1 mutations and 24.0% of all mutations identified. Together with the BRCA1 c.3331_3334delCAAG mutation, these mutations constitutes about 35% of the identified mutations and more than 50% of the BRCA1 pathogenic mutations. Interestingly, six new mutations were identified. Additionally, 39 out of the 44 pathogenic mutations identified were not previously reported in the Brazilian population. Besides, 36 different variants of unknown significance (VUS) were identified. Regarding ancestry, average ancestry proportions were 70.6% European, 14.5% African, 8.0% Native American and 6.8% East Asian.

Materials and methods

This study characterized 349 Brazilian families at-risk for HBOC regarding their germline BRCA1/BRCA2 status and genetic ancestry.

Conclusions

This is the largest report of BRCA1/BRCA2 assessment in an at-risk HBOC Brazilian population. We identified 21.5% of patients harboring BRCA1/BRCA2 mutations and characterized the genetic ancestry of a sample group at-risk for hereditary breast cancer showing once again how admixed is the Brazilian population. No association was found between genetic ancestry and mutational status. The knowledge of the mutational profile in a population can contribute to the definition of more cost-effective strategies for the identification of HBOC families.

Identification of hereditary cancer in the general population: development and validation of a screening questionnaire for obtaining the family history of cancer

One of the challenges for Latin American countries is to include in their healthcare systems technologies that can be applied to hereditary cancer detection and management. The aim of the study is to create and validate a questionnaire to identify individuals with possible risk for hereditary cancer predisposition syndromes (HCPS), using different strategies in a Cancer Prevention Service in Brazil. The primary screening questionnaire (PSQ) was developed to identify families at‐risk for HCPS. The PSQ was validated using discrimination measures, and the reproducibility was estimated through kappa coefficient. Patients with at least one affirmative answer had the pedigree drawn using three alternative interview approaches: in‐person, by telephone, or letter. Validation of these approaches was done. Kappa and intraclass correlation coefficients were used to analyze data's reproducibility considering the presence of clinical criteria for HCPS. The PSQ was applied to a convenience sample of 20,000 women of which 3121 (15.6%) answered at least one affirmative question and 1938 had their pedigrees drawn. The PSQ showed sensitivity and specificity scores of 94.4% and 75%, respectively, and a kappa of 0.64. The strategies for pedigree drawing had reproducibility coefficients of 0.976 and 0.850 for the telephone and letter approaches, respectively. Pedigree analysis allowed us to identify 465 individuals (24.0%) fulfilling at least one clinical criterion for HCPS. The PSQ fulfills its function, allowing the identification of HCPS at‐risk families. The use of alternative screening methods may reduce the number of excluded at‐risk individuals/families who live in locations where oncogenetic services are not established.

Clinical Cancer Genetics Disparities among Latinos

The three major hereditary cancer syndromes in Latinos (Hereditary Breast and Ovarian Cancer, Familial Adenomatous Polyposis and Lynch Syndrome) have been shown to exhibit geographic disparities by country of origin suggesting admixture-based disparities. A solid infrastructure of clinical genetics geared towards diagnosis and prevention could aid in reducing the mortality of these cancer syndromes in Latinos. Currently, clinical cancer genetic services in Latin America are scarce. Moreover, limited studies have investigated the mutational spectrum of these cancer syndromes in Latinos resulting in gaps in personalized medicine affecting diagnosis, treatment and prevention. The following commentary discusses available genotype and clinical information on hereditary cancer in Latinos and highlights the limited access for cancer genetic services in Latin America including barriers to genetic testing and alternatives for providing better access to genetic services. In this review, we discuss the status of clinical genetic cancer services for both US Latinos and those Latinos living in Latin America.

Oncogenetics service and the Brazilian public health system: the experience of a reference Cancer Hospital

The identification of families at-risk for hereditary cancer is extremely important due to the prevention potential in those families. However, the number of Brazilian genetic services providing oncogenetic care is extremely low for the continental dimension of the country and its population. Therefore, at-risk patients do not receive appropriate assistance. This report describes the creation, structure and management of a cancer genetics service in a reference center for cancer prevention and treatment, the Barretos Cancer Hospital (BCH). The Oncogenetics Department (OD) of BCH offers, free of charge, to all patients/relatives with clinical criteria, the possibility to perform i) genetic counseling, ii) preventive examinations and iii) genetic testing with the best quality standards. The OD has a multidisciplinary team and is integrated with all specialties. The genetic counseling process consists (mostly) of two visits. In 2014, 614 individuals (371 families) were seen by the OD. To date, over 800 families were referred by the OD for genetic testing. The support provided by the Oncogenetics team is crucial to identify at-risk individuals and to develop preventive and personalized behaviors for each situation, not only to the upper-middle class population, but also to the people whose only possibility is the public health system.

Screening for germline BRCA1, BRCA2, TP53 and CHEK2 mutations in families at-risk for hereditary breast cancer identified in a population-based study from Southern Brazil

In Brazil, breast cancer is a public health care problem due to its high incidence and mortality rates. In this study, we investigated the prevalence of hereditary breast cancer syndromes (HBCS) in a population-based cohort in Brazils southernmost capital, Porto Alegre. All participants answered a questionnaire about family history (FH) of breast, ovarian and colorectal cancer and those with a positive FH were invited for genetic cancer risk assessment (GCRA). If pedigree analysis was suggestive of HBCS, genetic testing of the BRCA1, BRCA2, TP53, and CHEK2 genes was offered. Of 902 women submitted to GCRA, 214 had pedigrees suggestive of HBCS. Fifty of them underwent genetic testing: 18 and 40 for BRCA1/BRCA2 and TP53 mutation screening, respectively, and 7 for CHEK2 1100delC testing. A deleterious BRCA2 mutation was identified in one of the HBOC probands and the CHEK2 1100delC mutation occurred in one of the HBCC families. No deleterious germline alterations were identified in BRCA1 or TP53. Although strict inclusion criteria and a comprehensive testing approach were used, the suspected genetic risk in these families remains unexplained. Further studies in a larger cohort are necessary to better understand the genetic component of hereditary breast cancer in Southern Brazil.

Knowledge about hereditary cancer of women with family histories of breast, colorectal, or both types of cancer

Usually, the mass media do not address hereditary cancer and their risk factors, nor are these topics discussed at the community level. We used an informative guide on cancer and hereditary cancer, followed by a questionnaire on these topics to investigate the relevant knowledge among women at high risk for hereditary breast and/or colorectal cancer from a population-based cohort. The cohort was composed of 81 Brazilian women with positive family histories of breast and/or colorectal cancer. Strauss and Corbin's Grounded Theory was used for qualitative analysis. The average age of the cohort was 49.9 years old. Three participants (3.9%) were illiterate, 45 (59.2%) had attended elementary school, 14 (18.4%) had secondary school, and 14 (18.4%) held higher education degrees. A total of 47 (54.3%) volunteers were unable to fully understand the information provided in the guide because they did not know the meaning of words such as metastasis, malignant, hereditary, sporadic, or oncogenetics. Notwithstanding, the acceptance of the educational tool utilized was satisfactory, and it enhanced the volunteers' interest in a better understanding of cancer and heredity. Thereby, we concluded that the low knowledge of this important subject and the unawareness about fundamental terms required for the comprehension of this specific type of neoplasm made us believe that the use of the informative guide can provide a great value when used previously to the genetic counseling consultations. Besides, educational tools of easy understanding should be part of everyday clinical practice, from primary to specialized patient care.

A systematic review of factors that act as barriers to patient referral to genetic services

Patients who might benefit from genetic services may be denied access through failure to be referred. To investigate the evidence on barriers to referral to genetic services, we conducted a systematic review of empirical evidence on this topic. Nine studies were included in the review. Barriers related to non-genetic healthcare professionals were: lack of awareness of patient risk factors, failure to obtain adequate family history, lack of knowledge of genetics and genetic conditions, lack of awareness of genetic services, inadequate coordination of referral and lack of genetics workforce. Those related to individuals affected by or at risk of a genetic condition were: lack of awareness of personal risk, lack of knowledge and/or awareness of medical history of family members and lack of knowledge of genetic services. Research on access to genetic services is heterogeneous; stronger empirical evidence is needed on factors that are barriers, and further research is needed to develop 'targeted interventions' for equitable access to genetic services in a range of populations.

Histological profile and age at diagnosis of breast and ovarian tumors: A register-based study in Espirito Santo, Brazil

Breast and ovarian cancers are important public health problems in Brazil. However, in various locations in the Brazilian territory these types of cancer remain poorly characterized. Therefore, this study aimed to compare data collected from the Pathology Services of two Oncology Reference Hospitals in Espirito Santo state (Brazil) with the data in previous Brazilian studies. Histological type frequency and age at diagnosis of breast and ovarian tumors between 2001-2004 and 2009-2010 were analyzed. Tumor size, histological grade, lymph node status, hormone receptor status [estrogen (ER) and progesterone receptors (PR)] as well as HER2 and Ki-67 marker status were obtained for the cases of infiltrating ductal carcinomas of the breast during the period 2009-2010. Categorical variables were described by their absolute and/or relative frequencies, while quantitative variables were expressed as the mean ± standard deviation and median, using 95% confidence intervals. Chi-square tests were performed to examine whether or not the studied variables differed by age at the time of diagnosis. Malignant breast tumors (1,758) and 119 malignant ovarian tumors were examined. Mean ages for malignant breast and ovarian tumors were 53.59 and 52.98 years, respectively. An increased tumor frequency in the age group of ≤35 years was observed for other malignant tumors of the breast during the period of 2009-2010, compared to 2001-2004. When considering only infiltrating ductal carcinomas with immunohistochemistry records available, there were 82.1% (133 cases) of ER⁺/PR⁺ tumors, 1.9% (3 cases) of ER^-/PR^-/HER2 3⁺ and 16.04% (26 cases) of ER^-/PR^-/HER2^- tumors. The findings of this study demonstrated detailed information concerning breast and ovarian tumor behavior in the Espirito Santo state (Brazil), allowing for a precise comparison with other populations (Brazilian or international), which may be helpful in the planning of prevention and treatment strategies.

Effects of a genetic counseling model on mothers of children with down syndrome: a Brazilian pilot study

Down syndrome occurs in approximately 1:600 live births. Genetic counseling is indicated for these families and may be beneficial for adaptation to the challenges that accompany by this diagnosis. Although the basic counseling goals are similar, there are many models of genetic counseling practiced around the world. The aim of this article is to report the results of a pilot study that evaluated the level of satisfaction with a model of service delivery of genetic counseling practiced in Brazil, the knowledge assimilated about Down syndrome and whether this process resulted in a feeling of well-being and psychological support. Thirty mothers of under 6-month-old children with Down syndrome were interviewed after having two sessions of genetic counseling in a public healthcare service within a period of 30 days. A semi-structured questionnaire was developed by the researchers to collect identification, socioeconomic and demographic data and to assess the client's satisfaction with the model of genetic counseling. Data were collected using both open and closed questions. The reported level of satisfaction was high. The knowledge assimilated about Down syndrome after only two sessions was considered technically vague by raters in 44 % of cases. Most mothers (96.7 %) reported that genetic counseling was beneficial and provided psychological support. The model was considered satisfactory, but further research is needed to identify ways to improve knowledge retention by this population. These results highlight the utility of referring families for genetic counseling when there is a suspicion of a diagnosis of Down syndrome.

[Perception of cancer causes and risk, family history and preventive behaviors of users in oncogenetic counseling]

The aims of the present study were to describe cancer causes and risk perception, and to associate behaviors adopted for the prevention of tumors and cancer family history in individuals with suspect of hereditary cancer syndromes. A convenience sample of 51 individuals was selected from an oncogenetic counseling outpatient clinic in a university hospital in the countryside of the state of São Paulo. An instrument adapted to Brazilian culture was used. The respondents considered their own risk as being the same as the population's risk, and family history was not statistically associated with the performing of preventive exams. These findings highlight the need for intervention by health professionals, especially nurses, who may conduct health education activities for this population, which is an essential component of nursing care in oncogenetics.

Genetic counseling for patients and families with hereditary breast and ovarian cancer in a developing Asian country: an observational descriptive study

Genetic counseling (GC) and genetic testing are vital risk management strategies in hereditary breast and ovarian cancer (HBOC) syndromes. Hitherto, cancer genetic testing amongst Asians has been described only in developed and high-income Asian countries. We studied the uptake and acceptance of GC and genetic testing services to Asian BRCA carriers in a middle-income country. A total of 363 patients were tested by full sequencing and large rearrangement analysis of both BRCA1 and BRCA2 genes in the Malaysian Breast Cancer (MyBrCa) Genetic Study. Of these, 49 index patients (13.5%) were found to carry deleterious mutations. GC pre- and post- result disclosures were provided and these groups of patients and their families were studied. GC and genetic testing were accepted by 82% of Malaysian patients at high risk for HBOC syndromes. However, risk assessment was limited by large, geographically dispersed, often polygamous or polyandrous families, and the lack of complete cancer registry. Cultural taboos about cancer diagnoses, social marginalization and lack of regulatory control of genetic discrimination were significant concerns. Only 78% of index patients informed their families of their risks and 11% of relatives came forward when offered free counseling and testing. Even when GC and genetic testing are provided at no cost, there remain significant societal and regulatory barriers to effective cancer genetic services in this underserved Asian population. Families believe there is a need for regulatory protection against genetic discrimination. Further studies are needed in the area of increasing awareness about the potential benefits of GC and genetic testing in Asians.

Epigenetic transgenerational actions of endocrine disruptors

Environmental factors have a significant impact on biology. Therefore, environmental toxicants through similar mechanisms can modulate biological systems to influence physiology and promote disease states. The majority of environmental toxicants do not have the capacity to modulate DNA sequence, but can alter the epigenome. In the event an environmental toxicant such as an endocrine disruptor modifies the epigenome of a somatic cell, this may promote disease in the individual exposed, but not be transmitted to the next generation. In the event a toxicant modifies the epigenome of the germ line permanently, then the disease promoted can become transgenerationaly transmitted to subsequent progeny. The current review focuses on the ability of environmental factors such as endocrine disruptors to promote transgenerational phenotypes.

Development and validation of a simple questionnaire for the identification of hereditary breast cancer in primary care

Background

Breast cancer is a significant public health problem worldwide and the development of tools to identify individuals at-risk for hereditary breast cancer syndromes, where specific interventions can be proposed to reduce risk, has become increasingly relevant. A previous study in Southern Brazil has shown that a family history suggestive of these syndromes may be prevalent at the primary care level. Development of a simple and sensitive instrument, easily applicable in primary care units, would be particularly helpful in underserved communities in which identification and referral of high-risk individuals is difficult.

Methods

A simple 7-question instrument about family history of breast, ovarian and colorectal cancer, FHS-7, was developed to screen for individuals with an increased risk for hereditary breast cancer syndromes. FHS-7 was applied to 9218 women during routine visits to primary care units in Southern Brazil. Two consecutive samples of 885 women and 910 women who answered positively to at least one question and negatively to all questions were included, respectively. The sensitivity, specificity and positive and negative predictive values were determined.

Results

Of the 885 women reporting a positive family history, 211 (23.8%; CI95%: 21.5–26.2) had a pedigree suggestive of a hereditary breast and/or breast and colorectal cancer syndrome. Using as cut point one positive answer, the sensitivity and specificity of the instrument were 87.6% and 56.4%, respectively. Concordance between answers in two different applications was given by a intra-class correlation (ICC) of 0.84 for at least one positive answer. Temporal stability of the instrument was adequate (ICC = 0.65).

Conclusion

A simple instrument for the identification of the most common hereditary breast cancer syndrome phenotypes, showing good specificity and temporal stability was developed and could be used as a screening tool in primary care to refer at-risk individuals for genetic evaluations.

Population prevalence of hereditary breast cancer phenotypes and implementation of a genetic cancer risk assessment program in southern Brazil

In 2004, a population-based cohort (the Núcleo Mama Porto Alegre - NMPOA Cohort) was started in Porto Alegre, southern Brazil and within that cohort, a hereditary breast cancer study was initiated, aiming to determine the prevalence of hereditary breast cancer phenotypes and evaluate acceptance of a genetic cancer risk assessment (GCRA) program. Women from that cohort who reported a positive family history of cancer were referred to GCRA. Of the 9218 women enrolled, 1286 (13.9%) reported a family history of cancer. Of the 902 women who attended GCRA, 55 (8%) had an estimated lifetime risk of breast cancer ≥ 20% and 214 (23.7%) had pedigrees suggestive of a breast cancer predisposition syndrome; an unexpectedly high number of these fulfilled criteria for Li-Fraumeni-like syndrome (122 families, 66.7%). The overall prevalence of a hereditary breast cancer phenotype was 6.2% (95%CI: 5.67-6.65). These findings identified a problem of significant magnitude in the region and indicate that genetic cancer risk evaluation should be undertaken in a considerable proportion of the women from this community. The large proportion of women who attended GCRA (72.3%) indicates that the program was well-accepted by the community, regardless of the potential cultural, economic and social barriers.