Deciphering Genetic Testing for Hereditary Cancer Diagnosis | BGI Insight


What is hereditary cancer?

Hereditary cancer is caused by germline mutations, typically following an inheritance pattern within a family. In contrast, sporadic cancer is caused by somatic mutations interacting with environmental factors and lacks any observable family inheritance pattern.

Clinical and genetic heterogeneity are distinctive characteristics of hereditary cancer. These cancers are generally represented by various tumor syndromes. There are hundreds of tumor-susceptibility genes associated with hereditary cancers.

For instance, BRCA1 and BRCA2 are the most prevalent tumor-susceptibility genes associated with hereditary breast cancer and ovarian cancer, while MLH1 and MSH2 genes are linked to Lynch syndrome and the TP53 gene to Li-Fraumeni syndrome.

Early detection and intervention of hereditary cancer can substantially enhance treatment outcomes and the overall prognosis for the patient.

It is important to note that certain rare genes with pathogenic mutations can be detected in hereditary cancers, such as the CFTR mutation, commonly associated with cystic fibrosis.

BGI Genomics webinar: Advancing Precision Oncology Through Genetic Panels

In a recent webinar titled "Advancing Precision Oncology Through Genetic Panels: Comprehensive Evaluation and Patient-Centric Care," experts Dr. Benjamin García-Bloj and Dr. Ahmet Uludağ shared crucial insights shaping the future of precision oncology, highlighting their exceptional performance.

During the webinar, Dr. García-Bloj introduced the audience to hereditary cancer testing, delved into ongoing clinical projects using NGS panels, and emphasized the significant benefits of hereditary cancer testing in precision oncology through real-world case studies.

Dr. Uludağ centered his discussion on advancing precision oncology in Turkey, highlighting the clinical significance of NGS technology. He clarified why larger panels are preferred for precision medicine recommendations, offering valuable insights into the evolving landscape of precision oncology.  

About the Speakers:  

Dr. Benjamin García-Bloj

Dr. Benjamin García-Bloj, a seasoned physician and Doctor in medical sciences, specializes in precision medicine and Genomics, particularly in oncology. With a decade-long tenure in academia and teaching, he is renowned internationally for his expertise. Dr. García-Bloj is currently working as Medical Director at Centro de Oncología de Precisión, Santiago, Chile.  

Dr. Ahmet Uludağ

Assoc. Dr. Ahmet Uludağ completed his doctoral studies in the Medical Genetics program at Eskişehir Osmangazi University. Until 2016, he served as an academician at Çanakkale Onsekiz Mart University Faculty of Medicine. Since 2018, he has been employed as a Medical Genetics specialist at Next Genetic Center, assuming the role of chairman of the board of directors at the same institution in 2021.

Watch Full Webinar

BGI Genomics: Roundtable on Hereditary Cancer with Experts from Turkey & China

In a recent roundtable discussion conducted by BGI Genomics, Professor Gary Lu and Dr. Ahmet Uludağ discussed their perspectives on the significance of genetic testing for diagnosing hereditary cancer. They emphasized the importance of understanding hereditary versus sporadic cancer, common tumor susceptibility genes, and the impact of genetic testing on treatment management.

Professor Gary Lu highlighted the importance of considering rare genes with pathogenic mutations in hereditary cancer diagnosis. He shared a case where a CFTR mutation was identified through panel testing, confirming hereditary cancer in a family. Lu stressed the necessity of genetic testing in cases of rare cancers to identify germ mutations.

Dr. Ahmet Uludağ underscored the importance of careful patient selection for genetic testing based on medical and family history. He mentioned guidelines recommending testing for certain cancers and predicts an increasing need for testing in the future. Dr. Uludağ also discussed different genetic testing methods and personalized management for patients with positive results.  

For cancer patients, the decision to undergo genetic testing for the diagnosis of hereditary tumors is complex and requires careful consideration of the patient's medical and family history. Identifying germline mutations in tumor-susceptibility genes, achieved through genetic testing using a blood sample, can facilitate the diagnosis of hereditary cancer.    

For patients, particularly those diagnosed at a young age or those facing multiple primary cancers, bilateral occurrences, or rare cancer types, genetic testing can significantly contribute to the diagnosis of hereditary cancer. Genetic testing also aids in guiding treatment decisions and assessing the risk of other cancers developing.

For example, a patient with vaginal melanoma underwent genetic testing and was subsequently diagnosed with hereditary melanoma due to the identification of a CDKN2A mutation.

Genetic testing methods currently available for the diagnosis of hereditary cancer include next-generation sequencing (NGS), polymerase chain reaction (PCR), and PCR amplification restriction endonuclease (REA) for single nucleotide polymorphisms (SNPs), multiplex ligation-dependent probe amplification (MLPA) for deletions and amplifications, and preimplantation genetic testing (PGT-M) for embryos.

About the Speakers:

Professor Gary Lu

Professor Gary Lu is a seasoned cancer researcher specializing in hereditary cancer. With nine years at MD Anderson Cancer Center, he now focuses on this field in China post-retirement, aiming to make impactful contributions to cancer treatment. Understanding genetic testing for hereditary cancer diagnosis

Dr. Ahmet Uludağ

Assoc. Dr. Ahmet Uludağ completed his doctoral studies in the Medical Genetics program at Eskişehir Osmangazi University. Until 2016, he served as an academician at Çanakkale Onsekiz Mart University Faculty of Medicine. Since 2018, he has been employed as a Medical Genetics specialist at Next Genetic Center, assuming the role of chairman of the board of directors at the same institution in 2021.

Watch Roundtable Part 1

Hereditary cancer risk management

The interpretation of test results is essential in genetic testing for families with a history of hereditary cancer. Positive results provide a straightforward diagnosis, but dealing with variants of uncertain significance (VUS) can be challenging and require careful interpretation. There must be a clear distinction between phenotype and genotype.

In addition to the test results, both the family's cancer history and clinical feature information (such as age, age of cancer occurrence, number of cancers, and whether the cancer is bilateral or rare cancer) are crucial for the management process.

There are three parts of management for hereditary cancer family:

1. Cancer patients: Patients should prioritize personalized treatment and monitor for signs of cancer recurrence (particularly minimal residual disease), the development of new primary cancers, and the occurrence of therapy-related leukemia.

2. Carriers: Education is important for tumor occurrence monitoring. Carriers must know what they need to pay attention to. For example, BRCA gene mutation carriers should know how to discover and manage breast nodes for early breast cancer detection, as well as monitor irregular menstruation for the early detection of ovarian cancer.

3. Non-cancer baby birth: Young carriers or young cancer patients planning to have children should be informed about the necessary tests to ensure the birth of a ‘non-cancer baby.’ PGT-M is available in most reproductive centers and is a good test to prevent the transplantation of fertilized eggs with mutated genes.

Genetic counseling for concerns about hereditary cancer

Individuals with a familial cancer history who wish to evaluate the risk of hereditary cancer should undergo professional cancer genetic counseling, both for the person undergoing testing and their family members.

There are three parts to genetic counseling:

1. Professional counseling: Patients, carriers, and the family must understand the risk of developing cancer throughout their lives and the types of cancer that could occur. They must know how to detect the occurrence of cancer and understand the necessary steps for early detection, diagnosis, and treatment of cancer. They must also engage in health management post-treatment.

2. Psychological counseling: Psychological counseling is important for the entire family, whether supporting the patient during treatment or recovery or helping carriers cope with the potential occurrence of cancer. Maintaining an optimistic mindset is essential for their overall well-being.

3. Ethical counseling: Ethical considerations may vary across systems, but it is crucial to adhere to principles outlined in policies. Patient or family autonomy remains important within any policy.

Diagnosis and treatment: The influence of personalized management in hereditary cancers

Personalized management can affect the diagnosis and treatment of hereditary cancers. For example, the status of homologous recombination deficiency (HRD) is critical in determining the effectiveness of the assessment of PARP inhibitors. This information guides clinicians in deciding whether to administer these drugs, particularly in cases of ovarian cancer. In mainland China, BGI Genomics offers HRD score testing.


BGI Genomics: Comprehensive hereditary cancer panels

BGI Genomics provides comprehensive hereditary cancer panels encompassing 90 genes associated with 25 types of hereditary cancers.

These panels enable a thorough analysis of genetic mutations, providing valuable insights for risk assessment, diagnosis, and treatment planning. This includes the detailed risk management and assessment information provided in BGI Genomics' genetic testing report.

BGI Genomics' expertise in sequencing and data analysis ensures the detection of various genetic mutations, including single nucleotide variants, insertions, deletions, and copy number variants. Notably, BGI Genomics has conducted over 40,000 BRCA1 and BRCA2 tests, with a VUS rate of 4% in ovarian cancer.

BGI Genomics' extensive testing capacity allows for efficiently processing a high volume of samples. The company maintains a strict quality management system to ensure authoritative genetic testing results.

Insights from BGI Genomics

When a family finds out that they have a hereditary cancer risk, how do you manage the entire family's sort of process for testing and the same kind of decision making through that?

Professor Gary Lu: "There are three key aspects to consider when dealing with hereditary cancer within a family.

The first aspect centers around the cancer patient. For individuals already diagnosed with cancer, personalized treatment is of utmost importance. After treatment, ongoing monitoring through tools like Minimal Residual Disease (MRD) assessments is critical to detect any potential recurrences.

Furthermore, vigilance is required to identify any new primary cancers, allowing for early diagnosis and swift intervention. This concern extends to sporadic cancer cases, with particular attention to therapy-related leukemia, which presents unique treatment challenges.

The second aspect that must be considered is the mutated gene carriers, who may not have developed cancer themselves. These carriers serve as a sort of "minister" guiding others in their family toward understanding and managing the hereditary cancer syndrome associated with the genetic mutation.

For instance, I had a patient with a specific genetic mutation related to breast and ovarian cancers. After genetic counseling, I advised her on how to monitor her health and when to take special precautions. A few months later, she reported feeling unwell despite no visible changes in her breast. However, irregular menstrual cycles, altered blood color, and abdominal pain raised concerns. I recommended a CA125 test, which revealed a ninefold increase over normal levels. Subsequent MRI scans detected an ovarian mass, prompting swift action. Detecting primary cancers in carriers is crucial, underscoring the importance of education and early intervention.

The third group encompasses young carriers who want to have children. In this scenario, our objective is to guide them through Preimplantation Genetic Testing (PGT) to ensure that their offspring are not born with cancer-related genetic mutations. PGT prevents the transfer of these mutations to the next generation, offering hope for cancer-free births."

Ahmet Uludağ: "Our approach involves several important steps in our clinic when we encounter families with a hereditary cancer history.

First and foremost, we provide genetic counseling to the family, offering genetic testing if deemed necessary. This initial step helps identify individuals who might be at risk for hereditary cancer and provides valuable information regarding screening and preventive measures.

Following genetic counseling and testing, we establish a plan for regular screenings. Those with a family history of hereditary cancer often require routine screenings, such as mammograms or colonoscopies, among others, to detect any potential issues at an early stage.

Additionally, we emphasize the significance of lifestyle modifications. Encouraging healthy choices, including maintaining a healthy weight, regular exercise, and abstaining from tobacco and alcohol, plays a pivotal role in reducing the risk of cancer development.

Finally, we place great emphasis on providing support and education to families dealing with hereditary cancer. Access to resources that offer guidance on coping with the emotional and psychological impact of a cancer diagnosis is crucial for these individuals and their loved ones. Comprehensive support and education are integral components of our approach to managing hereditary cancer in families."

BGI Genomics was chosen as the central laboratory for a pivotal cancer study in collaboration with AstraZeneca, and the data generated from this partnership played a significant role in obtaining FDA approval for Olaparib in January 2018. Could you shed some light on the unique strengths and capabilities of BGI Genomics that made it an ideal choice for conducting these crucial tests?

Professor Gary Lu: "BGI Genomics offers comprehensive hereditary cancer panels encompassing 90 genes associated with 20 different types of hereditary cancers. These panels facilitate a thorough examination of genetic mutations, providing valuable insights for risk assessment, diagnosis, and treatment planning.

The expertise of BGI Genomics sequencing and data analysis specialists ensures the detection of various types of genetic mutations, including single nucleotide variants, insertions, deletions, and copy number variations, which are paramount in cancer research and diagnosis.

One of BGI Genomics' remarkable strengths lies in its extensive experience, having conducted over 40,000 BRCA1 and BRCA2 tests. This experience extends to ovarian cancer, where BRCA1 and BRCA2 mutations play a significant role, with a notable reduction in the rate of BRCA1 and BRCA2 mutations detected, particularly in ovarian cancer cases, dropping to as low as 4%. Ovarian and breast cancers are prevalent among women and often have hereditary components.

Moreover, BGI Genomics upholds rigorous quality management standards, ensuring the delivery of reliable and authorized genetic testing results. Personally, I have had a close and successful collaboration with BGI Genomics, recommending many of my patients utilize their genetic testing services for hereditary cancer."

Watch Roundtable Part 2

About BGI SENTIS™ Comprehensive Hereditary Cancer Panel

BGI SENTIS™ Comprehensive Hereditary Cancer Panels provides information on 79 genes associated with 24 different types of hereditary cancer, including some of the most commonly occurring cancers such as hereditary breast, ovarian, colorectal, pancreatic, prostate, and stomach cancer. Click here to learn more.

About BGI Genomics:

BGI Genomics, headquartered in Shenzhen, China, is the world's leading integrated solutions provider of precision medicine. Our services cover more than 100 countries and regions, involving more than 2,300 medical institutions. In July 2017, as a subsidiary of BGI Group, BGI Genomics (300676.SZ) was officially listed on the Shenzhen Stock Exchange.

First Published: News Medical