Performance of BOADICEA and BRCAPRO genetic models and of empirical criteria based on cancer family history for predicting BRCA mutation carrier probabilities: a retrospective study in a sample of Italian cancer genetics clinics

Validation of the BOADICEA model for predicting the likelihood of carrying pathogenic variants in eight breast and ovarian cancer susceptibility genes

BOADICEA is a comprehensive risk prediction model for breast and/or ovarian cancer (BC/OC) and for carrying pathogenic variants (PVs) in cancer susceptibility genes. In addition to BRCA1 and BRCA2, BOADICEA version 6 includes PALB2, CHEK2, ATM, BARD1, RAD51C and RAD51D. To validate its predictions for these genes, we conducted a retrospective study including 2033 individuals counselled at clinical genetics departments in Denmark. All counselees underwent comprehensive genetic testing by next generation sequencing on suspicion of hereditary susceptibility to BC/OC. Likelihoods of PVs were predicted from information about diagnosis, family history and tumour pathology. Calibration was examined using the observed-to-expected ratio (O/E) and discrimination using the area under the receiver operating characteristics curve (AUC). The O/E was 1.11 (95% CI 0.97-1.26) for all genes combined. At sub-categories of predicted likelihood, the model performed well with limited misestimation at the extremes of predicted likelihood. Discrimination was acceptable with an AUC of 0.70 (95% CI 0.66-0.74), although discrimination was better for BRCA1 and BRCA2 than for the other genes in the model. This suggests that BOADICEA remains a valid decision-making aid for determining which individuals to offer comprehensive genetic testing for hereditary susceptibility to BC/OC despite suboptimal calibration for individual genes in this population.

Identification of women at risk of hereditary breast-ovarian cancer among participants in a population-based breast cancer screening

Women attending mammography screening may benefit from family history (FH) assessment for the identification of Hereditary Breast Ovarian Cancer (HBOC). Few studies explored the efficacy of tailored educational interventions in driving the attention on FH-associated risk among these women. To compare the efficacy of two educational tools in increasing attention towards FH, 6.802 women with a negative mammography were randomized to receive a note on FH of breast/ovarian cancer (letter A, n = 3.402) or a note with details on possible implication of FH patterns (letter B, n = 3.200). Upon women's request, a brief questionnaire was administered on phone at the Screening Unit (S.U.) to select those eligible for an in-depth FH evaluation at the Genetic Unit (G.U.). Each affected relative was scored 1-3 according to type of cancer, age at diagnosis, gender, position in the family tree. In all, 401 women contacted the S.U.: 244 (6.6%) in group A and 177 (5.2%) in group B (adjOR 1.27; 95%CI 1.03-1.56). FH scored ≥ 3 for 164 women: 177 (47.5%) in group B and 224 (35.7%) in group A, (adjOR 1.59, 95%CI 1.06-2.38). The G.U. traced and interviewed 148 women, 65 (43.9%) were offered an in-person consultation: 38 attended and 30 were eligible for testing. A test was performed for 24 women: no BRCA pathogenic variant was found. Among mammographic screening attendees, educational material with a simple description of FH may improve self-referral of women deserving an in-depth evaluation for HBOC identification. Additional educational efforts are needed to enhance the efficiency of the intervention.

Predicting cancer risk based on family history

A new software package provides more accurate cancer risk prediction profiles and has the ability to integrate more genes and cancer types in the future.

Population frequencies of pathogenic alleles of BRCA1 and BRCA2: analysis of 173 Danish breast cancer pedigrees using the BOADICEA model

The Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) calculates the probability that a woman carries a pathogenic variant in BRCA1 or BRCA2 based on her pedigree and the population frequencies of pathogenic alleles of BRCA1 (0.0006394) and BRCA2 (0.00102) in the United Kingdom (UK). BOADICEA allows the clinician to define the population frequencies of pathogenic alleles of BRCA1 and BRCA2 for other populations but only includes preset values for the Ashkenazy Jewish and Icelandic populations. Among 173 early-onset breast cancer pedigrees in Denmark, BOADICEA discriminated well between carriers and non-carriers of pathogenic variants (area under the receiver operating characteristics curve: 0.81; 95% CI 0.74-0.86) but underestimated the frequency of carriers of pathogenic variants in BRCA1 or BRCA2 as measured by the observed-to-expected ratio (O/E 1.83; 95% CI 1.18-2.84). This reflects findings from older studies of BOADICEA in UK, German, Italian, and Chinese populations, all accounting for the different calibration for different carrier probabilities. To improve the performance of BOADICEA for non-UK populations, we developed a method to derive population frequencies of pathogenic alleles of BRCA1 and BRCA2. Compared to the UK population frequencies, we estimated the Danish population frequencies of pathogenic alleles to be higher for BRCA1 (0.0015; 95% CI 0.00064-0.0034) and lower for BRCA2 (0.00052; 95% CI 0.00018-0.0017) after adjusting for the different calibration of BOADICEA for different carrier probabilities. Incorporating additional population frequencies into BOADICEA could improve its performance for non-UK populations.

Constitutive BRCA1 Promoter Hypermethylation Can Be a Predisposing Event in Isolated Early-Onset Breast Cancer

Early age at onset of breast cancer (eoBC) is suggestive of an increased genetic risk. Although genetic testing is offered to all eoBC-affected women, in isolated cases the detection rate of pathogenic variants is <10%. This study aimed at assessing the role of constitutive promoter methylation at BC-associated loci as an underlying predisposing event in women with eoBC and negative family history. Promoter methylation at 12 loci was assessed by the MassARRAY technology in blood from 154 BRCA1/2 negative patients with eoBC and negative family history, and 60 healthy controls. Hypermethylation was determined, within each promoter, by comparing the patient’s mean methylation value with thresholds based on one-sided 95% bootstrap confidence interval of the controls’ mean. Three patients had hypermethylated results, two at BRCA1 and one at RAD51C. Analyses on tumor tissue from the patient exceeding the highest threshold at BRCA1 revealed a mean methylation >60% and loss of heterozygosity at chromosome 17q. The patient hypermethylated at RAD51C showed low methylation in the tumor sample, ruling out a role for methylation-induced silencing in tumor development. In isolated eoBC patients, BRCA1 constitutive promoter methylation may be a predisposing event. Further studies are required to define the impact of methylation changes occurring at BC-predisposing genes and their role in tumorigenesis.

Performance of BRCA1/2 mutation prediction models in male breast cancer patients

To establish whether existing mutation prediction models can identify which male breast cancer (MBC) patients should be offered BRCA1 and BRCA2 diagnostic DNA screening, we compared the performance of BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm), BRCAPRO (BRCA probability) and the Myriad prevalence table ("Myriad"). These models were evaluated using the family data of 307 Dutch MBC probands tested for BRCA1/2, 58 (19%) of whom were carriers. We compared the numbers of observed vs predicted carriers and assessed the Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) for each model. BOADICEA predicted the total number of BRCA1/2 mutation carriers quite accurately (observed/predicted ratio: 0.94). When a cut-off of 10% and 20% prior probability was used, BRCAPRO showed a non-significant better performance (observed/predicted ratio BOADICEA: 0.81, 95% confidence interval [CI]: [0.60-1.09] and 0.79, 95% CI: [0.57-1.09], vs.

BRCAPRO

1.02, 95% CI: [0.75-1.38] and 0.94, 95% CI: [0.68-1.31], respectively). Myriad underestimated the number of carriers in up to 69% of the cases. BRCAPRO showed a non-significant, higher AUC than BOADICEA (0.798 vs 0.776). Myriad showed a significantly lower AUC (0.671). BRCAPRO and BOADICEA can efficiently identify MBC patients as BRCA1/2 mutation carriers. Besides their general applicability, these tools will be of particular value in countries with limited healthcare resources.

Comparison between CaGene 5.1 and 6.0 for BRCA1/2 mutation prediction: a retrospective study of 150 BRCA1/2 genetic tests in 517 families with breast/ovarian cancer

During the past years, several empirical and statistical models have been developed to discriminate between carriers and non-carriers of germline BRCA1/BRCA2 (breast cancer 1, early onset/breast cancer 2, early onset) mutations in families with hereditary breast or ovarian cancer. Among these, the BRCAPRO or CaGene model is commonly used during genetic counseling, and plays a central role in the identification of potential carriers of BRCA1/2 mutations. We compared performance and clinical applicability of BRCAPRO version 5.1 vs version 6.0 in order to assess diagnostic accuracy of updated version. The study was carried out on 517 pedigrees of patients with familial history of breast or ovarian cancer, 150 of which were submitted to BRCA1/2 mutation screening, according to BRCAPRO evaluation or to criteria based on familial history. In our study, CaGene 5.1 was more sensitive than CaGene 6.0, although the latter showed a higher specificity. Both BRCAPRO versions better discriminate BRCA1 than BRCA2 mutations. This study evidenced similar performances in the two BRCAPRO versions even if the CaGene 6.0 has underestimated the genetic risk prediction in some BRCA mutation-positive families. Genetic counselors should recognize this limitation and during genetic counseling would be advisable to use a set of criteria in order to improve mutation carrier prediction.

Mutation detection rates associated with specific selection criteria for BRCA1/2 testing in 1854 high-risk families: A monocentric Italian study

BACKGROUND

BRCA mutation screening is frequently offered on the basis of the fulfillment of empirical selection criteria, thought to be indicative of a genetic predisposition to breast/ovarian cancer (BrCa/OvCa). This study aimed to evaluate, in a large cohort of BrCa/OvCa families, the mutation detection rate (DR) associated with specific clinical features and the relative performance of the employed selection criteria.

METHODS

BRCA gene analysis was performed on 1854 family probands. The Fisher exact test was used to compare the DRs associated with different clinical features. In a subset of families fulfilling only mutually exclusive criteria, odds ratios and 95% CI were estimated to test the relative effectiveness of each criterion.

RESULTS

The overall DR was 29.3%. Among BrCa-only families, the DRs were significantly higher in the presence of early-onset compared with late-onset cases, and of bilateral compared with unilateral cases. In families with bilateral cases, ages at diagnosis of both the first and second tumour were significantly lower in mutation carriers. In families fulfilling mutually exclusive criteria, OvCa was the best predictor of BRCA mutations, with DRs (range: 31.8%-80.0%) significantly higher compared with the other criteria. Conversely, isolated early-onset BrCa and three or more late-onset BrCa displayed significantly lower predictive values (7.9% and 7.2%, respectively).

CONCLUSIONS

The observed estimates, albeit confirming a DR above 10% for most of the considered criteria, highlighted some relevant differences among them. Such differences should be taken into account in the identification of patients who might benefit from genetic counselling and subsequent testing.

Ovarian Cancer and BRCA1/2 Testing: Opportunities to Improve Clinical Care and Disease Prevention

Without prevention or screening options available, ovarian cancer is the most lethal malignancy of the female reproductive tract. High-grade serous ovarian cancer (HGSOC) is the most common histologic subtype, and the role of germline BRCA1/2 mutation in predisposition and prognosis is established. Given the targeted treatment opportunities with PARP inhibitors, a predictive role for BRCA1/2 mutation has emerged. Despite recommendations to provide BRCA1/2 testing to all women with histologically confirmed HGSOC, uniform implementation remains challenging. The opportunity to review and revise genetic screening and testing practices will identify opportunities, where universal adoption of BRCA1/2 mutation testing will impact and improve treatment of women with ovarian cancer. Improving education and awareness of genetic testing for women with cancer, as well as the broader general community, will help focus much-needed attention on opportunities to advance prevention and screening programs in ovarian cancer. This is imperative not only for women with cancer and those at risk of developing cancer but also for their first-degree relatives. In addition, BRCA1/2 testing may have direct implications for patients with other types of cancers, many of which are now being found to have BRCA1/2 involvement.

Germline BRCA1/2 testing practices in ovarian cancer: Current state and opportunities for new directions

PURPOSE

Given the implications for clinical care and prevention in identifying a BRCA1/2 mutation, the objective of this study was to determine current BRCA1/2 testing practices in ovarian cancer and to identify future directions.

METHODS

Two parallel complementary web-based surveys were sent by email to representatives of Gynecologic Cancer InterGroup (GCIG) and to referral centers in countries with and without GCIG membership. Questions posed addressed indications of BRCA1/2 testing for ovarian cancer; the implication of genetic counseling; and prevention strategies employed.

RESULTS

Among the GCIG, 22 collaborative groups from 19 countries answered the survey. For the complementary survey, 22 referral centers replied. Findings show criteria to offer germline BRCA1/2 testing are mixed; 55% of GCIG members based testing decisions on histology and, among all respondents the main testing criterion remains family history. Typically, genetic counseling is scheduled prior to the genetic testing; however, if negative, results may not be communicated by the genetic counselor. Time between testing and communicating results varies widely between the groups. Lastly, recommendations to relatives regarding risk reduction surgery are inconsistent.

CONCLUSION

Our study highlights the need for collaborative efforts to devise international guidelines around BRCA1/2 testing in ovarian cancer to ensure consistent BRCA1/2 screening practices are adopted. Clinical practice is evolving rapidly and as BRCA1/2 testing is expected to become more widespread, new approaches are required. Coordinating BRCA1/2 testing practices is crucial in terms of care for the patient diagnosed with ovarian cancer but also towards cancer prevention for affected family members.

A targeted approach to genetic counseling in breast cancer patients: the experience of an Italian local project

AIMS AND BACKGROUND

Patients with hereditary breast cancer (BC) may benefit from genetic counseling and testing for detection of causative mutations, definition of therapeutic and preventive strategies, and identification of at-risk relatives. Italy has few oncogenetic centers and genetic evaluation of all patients with BC is not feasible. Moreover, lack of uniformity in the selection of patients generates inappropriate referral to the geneticist. We designed a model that may represent a reproducible way to select patients at risk for hereditary BC, with the aims of rationalizing access to genetic centers and improving clinical management and surveillance.

METHODS

The genetic unit of a Cancer Center and the Departments of Oncology from 2 public Hospitals in Milan were involved in the project. After training sessions at the genetic unit, operators from the 2 hospitals evaluated all patients with BC attending a first oncologic visit, through a specific interview. Patients considered at risk of hereditary BC attended counseling at the genetic unit.

RESULTS

Of 419 patients, 61 (14.5%) were eligible for genetic counseling after the interview. Of these, 46 (10.9%) strictly met testing criteria. Overall, 52 (12.4%) patients underwent genetic counseling and 47 were tested for BRCA1/BRCA2 mutation. After genetic test results, the available options for treatment/surveillance were discussed by a multidisciplinary team, according to the level of genetic risk.

CONCLUSIONS

It is possible to improve the process of referring patients with suspected hereditary BC for genetic risk assessment. The application of clinical screening reduced the genetics unit's workload and enabled optimization of time and resources.

BRCA1 gene variant p.P142H associated with male breast cancer: a two-generation genealogic study and literature review

Breast cancer occurs rarely in male patient. BRCA1 gene mutation seems to be related to male breast cancer, but its role is not clearly defined. We have identified in a male patient affected by breast cancer the BRCA1 gene variant p.P142H. We performed a literature research using the keywords "male breast cancer", "male breast cancer mutations" and "BRCA" and we reviewed the cases. We found ew other studies regarding BRCA1 variant p.P142H, about female subjects. At the moment, BRCA1 gene variant p.P142H is not certainly classified as neutral or deleterious. Genetic testing for BRCA1 and BRCA2 and PALB2 mutation gene has been performed on our patient. Segregation analysis for this p.P142H BRCA1 variant has been extended to the second generation of the family. Genetic tests revealed a clear inheritance regarding the BRCA1 gene p. P142H variant. Of the eight patients with this specific genetic mutation, four presented breast cancer (bilateral in one case), two female and two male. None of the subjects in the family without the BRCA1 gene variant p. P142H presented breast cancer or other BRCA1 gene mutation-related cancers. Our analysis suggests that the BRCA1 gene variant p.P142H mutation is related with male breast cancer. Starting from these data, it can be inferred that more studies on MBC and its relation with the BRCA1 gene mutation P142H variant must be undertaken to improve prognostic and therapeutic strategies.

Genetic risk assessment for breast and gynecological malignancies

PURPOSE OF REVIEW

Breast cancer and gynecological cancers impact a significant portion of women each year. Identifying women at high risk is essential for implementation of screening and risk reduction recommendations. Risk assessment for these cancers involves an evaluation of many factors. This review discusses an overview of hereditary breast and gynecological cancers and the process of a cancer genetic risk assessment.

RECENT FINDINGS

Risk assessment models for breast cancer should be used with caution, especially in populations in which they are not validated. Additionally, the BRCAPRO model may underestimate the likelihood of BRCA mutations in certain populations.The utilization of next-generation sequencing panels is increasing. Benefits and limitations of panel testing are described in the literature. There are currently no guidelines for the use of panel testing; however, some reports of institutional experiences and recommendations are available.

SUMMARY

Cancer genetic risk assessment is complex, and models developed to estimate risk may not apply to all populations. Identifying genetic factors related to cancer risk is also becoming increasingly complex with the clinical implementation of panel testing. This testing approach should be critically evaluated by healthcare providers. Further research is needed to create evidence-based guidelines for panel testing and management recommendations for moderately penetrant genes.