Genetic Testing for Brain Cancer

When you have a brain tumour, you may wonder what caused it and whether it’s genetic, or if your genes or DNA play a role.  

DNA is the genetic code that carries instructions for how living things grow and function. It’s sometimes called a ‘blueprint’ of how cells should behave. However, if the DNA and thus the genetic code mutates, the instructions for the cells can change. In the context of cancer, genetic mutations lead to uncontrolled cell growth and cause a disruption in the process of programmed cell death (apoptosis) resulting in the formation of tumours. Tumours can be benign (non-cancerous) or malignant (cancerous). Malignant tumours, or cancers, have the potential to invade nearby tissues and spread to other parts of the body, a process known as metastasis. 

Researchers are studying these genetic mutations to better understand how genes may contribute to the development of a malignant brain tumour.   This emerging research is providing insights into the genetic origin of a brain tumour, and although the mutation in a tumour is always genetic, research has shown that only a very small portion of brain tumours can be attributed to an inherited genetic disorder. 

Genetic testing is now being explored as a tool to tackle the unpredictable nature of brain cancer and to obtain a better understanding and management of the disease. As research continues, the study of genetics and brain cancer could lead to the development of new treatments for brain cancers in the future. 

This blog covers how specialised testing has evolved to be useful in understanding brain cancer at a genetic level, and how it is helping doctors diagnose tumours and to determine which treatments can be provided for specific genetic mutations.   

Is There a Genetic Test for Brain Cancer? 

Genetic testing is a tool used to better understand the origin of a tumour and how a cancer may develop by looking into gene mutations.  

Today, genetic testing is widely used to assess whether people have an increased risk of developing some types of cancer. This is being done for different types of cancer, such as breast cancer, ovarian cancer, colorectal cancer, melanoma, prostate, and pancreatic cancers, among others. For example, in breast cancer, genetic testing can identify mutations in the BRCA1 and BRCA2 (Breast Cancer gene 1 and Breast Cancer gene 2) genes. Testing can show if there are changes in these genes that can lead to an increased risk of developing breast cancer. To note, not everyone with mutations in BRCA1 or BRCA2 will get cancer but they may be at greater risk. 

For brain cancer, there are a few known hereditary genetic conditions, such as Li-Fraumeni, Neurofibromatosis, and Von Hippel-Lindau disease that involve mutations in genes that normally suppress tumour growth. In these conditions, there is an increased risk of developing cancer, including in the brain. 

In contrast to research being done to identify which patients have a higher chance of developing brain cancer due to genetic causes, much of the current research and development in the field of brain cancer genetics is aimed at understanding how these cancers develop and respond to treatments.   

By the time a brain tumour is identified, getting a biopsy or blood draw and studying the DNA changes within the tumour can be helpful in identifying the characteristics of the tumour. This information can help the physician with the final diagnosis of a tumour after initial tests have been done and may help to determine a treatment plan.  

Whole Genome Sequencing 

The approach of identifying which underlying genes are related to your cancer is done by looking into your tumour’s DNA. Think of DNA as an encyclopedia. In the past, when scientists studied cancer, they only read a few pages of it, mainly the parts about family history and certain ‘known’ genes. Now, due to many technological advances, they’re able to read the entire volume in less time. This new approach is called “whole genome sequencing”. The aim is to develop a thorough understanding of human DNA, not just a few pages of it. 

The parts of our DNA that make up our genes are quite small, only about 1-2%. The rest of our DNA was once thought to be “junk” because it doesn’t create genes. This “junk DNA” or “non-coding DNA” is now known to be important – it contains elements that can play a role in regulating “coding DNA” and therefore can play a role in the development of a tumour. Now being able to look at the whole encyclopedia, including coding and non-coding DNA, the benefit of whole genome sequencing has been realised and is a key benefit of new technology to look at all the DNA. 

Considering this, it is important to mention most brain cancers aren’t inherited (about 90-95%).  

Personalised Cancer Care   

Whole genome sequencing can also be performed on brain cancer cells (although it is worth noting it is currently not always done and is not standard of care). This helps in identifying specific gene mutations in the cancer cells, creating a detailed profile of the tumour. This profile, created by comparing the tumour DNA to your DNA, allows the physician to identify mutations that are present in your tumour cells, that are not in your normal DNA. Much like a fingerprint is unique to an individual, this profiling can determine what is unique in your tumour cell and may help guide doctors in selecting treatments that specifically attack your tumour’s unique characteristics. 

Previously, a cancer diagnosis often involved examining tumour samples under a microscope, a process that relied on a doctor’s skill and the quality of the tumour sample taken during surgery. Advanced genetic testing enables doctors to pinpoint what made each tumour grow, in a more structured way, not only have to rely on a doctor’s skill and interpretation under the microscope. Take, for example, low-grade glioma, a type of brain cancer. Patients with seemingly identical tumours were known to have very different experiences and physicians weren’t sure why. Genetic testing revealed that these tumours looked similar on the outside but weren’t from the inside. Some of the tumours had genetic characteristics which made them resist treatment better. This explained why some patients had not been responding well to treatment. This insight allowed doctors to tailor treatment more effectively, by identifying which patients benefitted from which treatment better. 

Clinical Trial Research for Genetic Factors Related to Brain Cancer  

Clinical trial research using whole genome sequencing is a new approach to brain cancer treatment development. This approach focuses on finding specific genetic changes in the cancer cells, which could support determining a diagnosis and subsequent targeted treatments. Targeted treatments are designed to handle a specific problem. In cancer research, including brain cancer research, scientists conduct studies on specific tumour mutations to see how well a targeted treatment can correct or fight against one particular error. There are also studies that look at treatments which can tackle multiple errors at once. 

This strategy, known as precision oncology, represents a shift from a more generalised approach in cancer treatment, such as traditional chemotherapy. Standard chemotherapy affects both cancerous and healthy cells, leading to numerous side effects that can significantly impact a patient’s well-being. Precision oncology is designed to specifically targets cancer cells. This focused approach aims to minimise the harm to healthy cells and allow oncologists to tailor treatments, known as targeted therapies, based on the unique genetic characteristics of each patient’s cancer, hoping to improve treatment efficacy, reducing side effects, and ultimately enhancing patient outcomes. 

Challenges for Targeted Therapies in Brain Cancer Treatment 

Researchers are developing strategies to improve both the diagnosis and treatment of brain cancer. However, this isn’t as easy as it sounds. Access to genomic testing can be limited, whole genome sequencing and targeted therapies can be expensive and may not be readily available or affordable for all patients. These factors may slow down access to possible treatments. 

Just because new genetic mutations are identified does not automatically mean medicines or therapies already exist to address them. And when they do exist, not all medicines are known to work on actionable mutations in different cancer types. Determining which mutations are targetable and directly contribute to tumour growth can be challenging, leading to some uncertainty in selecting the most effective treatment. However, ongoing research aims to address these challenges. 

Summary 

Advances in genetic testing are shifting the diagnosis and treatment of brain patients with brain cancer. The evolution of genetic testing technologies has been instrumental to these advancements. Developments in genetic testing also allow for the use of therapies targeting cancer cells more specifically, which could prevent the side effects often associated with traditional chemotherapy and other therapies that affect not only cancer cells but also healthy cells. Even with targeted therapies, precise targeting without harming healthy tissue remains a challenge. It’s worth noting that all the research on genetic mutations and corresponding targeted therapies is very new and therefore many patients receive surgery and chemo/radiotherapy before potentially receiving targeted therapy, as determined by their treating physician. The continued study of precise diagnostics and selection of targeted therapies matched to the individual characteristics of each patient’s cancer can help advance improving patient outcomes. 

myTomorrows is dedicated to helping patients with brain cancer. We can support with finding, and if patients wish so, helping with accessing brain cancer clinical trials. Contact us here to get started and speak with one of our patient navigators. You can also read more about brain tumours and our guide to glioblastoma treatment options.

The information in this blog is not intended as a substitute for a medical consultation. Always consult a doctor before receiving a diagnosis or treatment.  

The myTomorrows team
Anthony Fokkerweg 61-2
1059CP Amsterdam
The Netherlands  

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