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New research on genetic risk and breast cancer

How a simple saliva test can reveal the risk of breast cancer in the Norwegian population.

A study by the University of Oslo, Oslo University Hospital and OÜ Antegenes looking into Polygenic Risk Scores (PRS) and breast cancer in Norway was recently published in the journal MDPI Cancer. PRS technology is a type of genetic test that can reveal an individual’s risk of developing cancer.

“The study was initiated to assess the possibility of using a combination of genetic markers for a given woman here in Norway to predict the risk of developing breast cancer over her life,” said Eivind Hovig, Professor at the Department of Bioinformatics at the University of Oslo, and one of the co-authors to the article.

Early detection

Every year, there are close to 4 200 new breast cancer cases and almost 600 deaths from breast cancer in Norway, according to reports from the Norwegian Cancer Registry. Early detection is crucial for survival, but almost 40 per cent of breast cancer cases are not diagnosed at an early stage.

“The results indeed indicate that it is entirely feasible to apply such a predictor meaningfully in a Norwegian context,” said Hovig.

Personalised screening

Current breast cancer screening in Norway is implemented for women at age 50-69, but approximately 20 per cent of breast cancer cases are diagnosed in younger women. These tests can potentially be used to identify younger women with a higher risk and lead to a more personalised screening approach.

“As the application of such a predictor may have implications for management of patients with high risk scores, it may lead to different screening strategies and a better understanding of the risk profiles of these patients,” added Hovig.

The PRS test used in the study was developed by the Estonian company Antegenes. The study was conducted as a part of AnteNOR, a project that investigates how PRS can be implemented for prevention and early detection of breast cancer in Norway.

Polygenic risk scores: a European cancer priority 

The EU is looking to polygenic risk scores to improve prevention and early detection of cancer

Polygenic risk scores (PRS) have become one of the focus areas for prevention and early detection of cancer in the European Union’s Mission on Cancer. 

“PRS tests can provide a measure of your personal risk of developing a specific disease due to your genes,” explained Krista Kruuv-Käo, project manager of AnteNOR, a project that investigates how PRS can be implemented for prevention and early detection of breast cancer in Norway. 

Europe’s Beating Cancer Plan outlines 10 flagship initiatives and number 7 focuses on how cancers develop: 

“Alongside the ‘Genomic for Public Health’ project, the European Initiative to Understand Cancer (UNCAN.eu), planned to be launched under the foreseen Mission on Cancer to increase the understanding of how cancers develop, will also help identify individuals at high risk from common cancers using the polygenic risk scores technique. This should facilitate personalised approaches to cancer prevention and care, allowing for actions to be taken to decrease risk or to detect cancer as early as possible.”

What about Norway?

There are about 4 200 new cases and almost 600 deaths due to breast cancer in Norway each year, according to reports from the Norwegian Cancer Registry.  

“Early detection of breast cancer can save lives, but approximately 40 per cent of breast cancer cases in Norway are not detected at an early stage. For breast cancer, 31 per cent of all diagnoses are due to genetic predisposition and many women develop cancer before they reach the screening age of 50,” Kruuv-Käo commented. 

There are already genetic tests in the Norwegian specialist healthcare service for monogenic pathogenic variants, such as BRCA1 and BRCA2, but not on a population-wide basis. PRS tests have not been implemented yet, although they are both cheaper and can identify more women with a moderate to high risk of developing breast cancer. 

Improving cancer screening

The results of the AnteNOR project were recently presented at a meeting organized by the Norwegian Cancer Mission Hub. 

“The project shows that PRS tests can be used for effective risk stratification for population-wide breast screening. By introducing genetic risk testing with PRS tests and monogenic testing, the women with moderate to high risk of developing breast cancer can be identified before the screening age of 50 years. With a personalised screening programme, some women may need to screen earlier and more often, while others can go to screenings less frequently in the future,” Kruuv-Käo explained. 

Estonia is already preparing for the introduction of a personalized breast cancer screening program, and the plan is to launch it this year. Will Norway follow? 

Guidance on polygenic risk scores

The Estonian provider of PRS tests Antegenes supports the recent guidance from the American College of Medical Genetics and Genomics.

Polygenic risk scores (PRS) have recently been the subject of statements by the American College of Medical Genetics and Genomics (ACMG). These scores are used in the clinical assessment of an individual’s genetic risk for certain diseases. In simple terms, PRS tests provide a statistical prediction of an individual’s increased clinical risk for a specific condition, such as cancer.

Antegenes, an Estonian provider of PRS tests, welcomes ACMG’s initiative and considers it a crucial step towards establishing best practices and guidelines for the widespread use of PRS technology.

Dr Peeter Padrik, CEO of Antegenes, explains: “The considerations by ACMG align with our guiding principles at Antegenes for the development and use of our polygenic risk score tests. Our clinical grade genetic tests are in use in several European countries, and we have already applied these principles in their development and in providing cancer prevention services.”

Understanding polygenic risk scores

ACMG’s statements emphasize several important points related to PRS testing. First, it is crucial to understand that PRS test results do not provide a definitive diagnosis of a disease, such as cancer. Instead, they offer a statistical prediction of an increased clinical risk. Antegenes ensures clarity on this matter by providing explicit information in their test materials.

Furthermore, a low PRS does not exclude the possibility of significant risk for the disease in question. PRS represents only one aspect of an individual’s hereditary risk, and there are other factors that can influence the development of tumors. Antegenes emphasizes the importance of considering PRS results within the context of other relevant clinical data.

Considerations for effective implementation

Another factor to consider is that PRS predictions may vary based on the population used as reference. Ethnic background plays a role in this variation. Antegenes addresses this by analyzing PRS performance using data from different ethnic groups and making necessary adjustments to the test results. They always include information about an individual’s ethnic group in their genetic testing process.

ACMG also highlights the importance of complementing PRS testing with monogenic testing in certain clinical scenarios where the underlying genetic cause is known or suspected. Antegenes fully supports this approach and recommends considering both PRS testing and monogenic pathogenic variant testing, aligning with established clinical guidelines.

Promoting evidence-based medical management

Antegenes agrees with ACMG’s stance that patients and healthcare providers should have informed discussions about the indications for PRS testing and how the results will be used in guiding medical management. They emphasize the importance of evidence-based PRS-based medical management and have developed clinical recommendations based on PRS risk levels and existing professional guidelines.

In summary, Antegenes fully supports ACMG’s statements and has taken into account the described limitations of PRS testing. They have implemented solutions, provided relevant information, and developed clinical recommendations based on available evidence for the prevention and screening of specific tumor types.

About

Antegenes is a member of Oslo Cancer Cluster. The Antenor implementational research project, focused on preventing breast cancer based on genetic risks, is currently underway in collaboration with Norwegian scientific and clinical partners and is scheduled to conclude by the end of 2023. The project partners are Oslo University Hospital, the University of Oslo, Vestre Viken Hospital Trust, Oslo Cancer Cluster and Antegenes.

More personalised breast cancer screening

A new clinical pilot offers personalised breast cancer screening to Norwegian women.

A new clinical pilot will investigate how women can receive more personalised breast cancer screening. Currently, women in the age group 50-69 are invited to mammogram screenings every second year in Norway, but 20 percent of breast cancer cases are diagnosed among younger women.

“This ‘one size fits all’ approach does not take into account the different breast cancer risks of individual women. A more personalised screening program might be beneficial for both women and society, both in terms of increased surveillance of persons at higher risk for breast cancer, as well as more targeted use of resources. My motivation as a breast radiologist is to work for a high-quality, evidence-based screening program for breast cancer, and this study is an exciting contribution in that respect,” said Tone Hovda, senior radiologist at Vestre Viken Hospital Trust, where the study is running.

Tone Hovda, senior radiologist, Vestre Viken Hospital Trust

Using innovative DNA analysis

Participants of the study will submit a saliva sample, which is sent to Estonia for a genetic data analysis done by the Estonian medical technology company and healthcare service provider Antegenes that has developed the genetic test AnteBC. The AnteBC test is a CE-certified medical device.

The test is used to map a range of gene variants that individually don’t give increased risk for breast cancer, but where the combination of several genes can result in an increased risk. This is called polygenic risk score (PRS) and has never been used in screening programmes in Norway before.

Saliva shows risk of breast cancer

The results from the test will show if the participant has an elevated genetic risk for breast cancer. If it doesn’t, the participant will be recommended to follow the ordinary screening programme for breast cancer in Norway.

If the test shows an elevated risk for breast cancer, the participant will be offered a control scheme, which may include a recommendation of starting regular mammography before they turn 50 years old and/or go to mammography more often than every two years.

“The study analyses a woman’s genetic predisposition to the development of breast cancer, and based on that, provides personalized clinical recommendations for the prevention and early detection of disease. In the pilot study, both a woman’s polygenic risk and, if necessary, the presence of rare single genes that increase the risk of breast cancer will be evaluated,” commented Peeter Padrik, CEO, Antegenes.

Participants will also answer a questionnaire to give background information, such as family history. If there is suspicion of elevated risk of hereditary familial disease, the participant may be offered genetic counselling and extended genetic testing according to current clinical practice.

Towards personalised screening

This initiative is part of the implementation research project AnteNOR, which aims to investigate how it will be possible to implement a more personalised screening programme for breast cancer in Norway, based on the individual’s genetic risk for disease.

The project partners are Oslo University Hospital, the University of Oslo, Vestre Viken Hospital Trust, Oslo Cancer Cluster and Antegenes. It has received funding from The Norway Grants Green ICT programme and runs between 2021-2024.

The clinical trial has received approval from the regional ethics committee and is registered in the database clinicaltrial.gov.

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