Brain Tumors Decoded: A Comprehensive Guide for Patients and Caregivers – Part III

Understanding the Importance of Molecular Profiling in Brain Tumors

Molecular profiling is a critical step in the diagnosis and treatment of brain tumors. This advanced testing analyzes the genetic and molecular characteristics of a tumor to provide a deeper understanding of its behavior, guiding treatment decisions and potentially expanding options for care. For patients with brain tumors, molecular profiling can be a game changer, helping to confirm the diagnosis, identify potential biomarkers, and determine whether targeted therapies or immunotherapies may be effective.

What Is Molecular Profiling?

Molecular profiling involves testing a tumor’s genetic material to identify specific mutations, biomarkers, or other molecular characteristics.¹⁶ This information can:

• Confirm diagnosis: Provide greater precision in distinguishing tumor types and subtypes
• Guide treatment decisions: Reveal mutations or biomarkers that may respond to targeted therapies, such as EGFR inhibitors or BRAF targeted treatments
• Inform clinical trial eligibility: Help determine whether a patient qualifies for cutting-edge therapies being studied in clinical trials

Biomarker testing, a key component of molecular profiling, identifies specific genetic or protein markers in the tumor that can indicate its sensitivity to certain treatments.

Why Molecular Profiling Matters

For brain tumors, treatment options are often limited, and molecular profiling can offer a roadmap for more personalized care. Key reasons to pursue molecular testing include:

• Expanding treatment options: Identifying actionable biomarkers or mutations can open the door to therapies that may not otherwise have been considered, such as targeted therapy or immunotherapy
• Improving precision in treatment: Understanding the tumor’s molecular makeup provides insights into its potential sensitivity or resistance to treatments, enabling more informed decisions
• Advancing immunotherapy: Immunotherapy, a growing area of brain tumor treatment, leverages the body’s immune system to fight cancer. Molecular profiling can help determine whether a tumor is likely to respond to therapies such as immune checkpoint inhibitors

How Molecular Profiling Is Performed

Molecular profiling is typically conducted using a sample of the tumor obtained through a biopsy or surgery. Tests may include:

• Genetic sequencing: Examines the DNA and RNA of the tumor for mutations
• Biomarker testing: Identifies specific proteins or genetic markers associated with treatment sensitivity
• Next-generation sequencing: Evaluates multiple genetic mutations simultaneously using a comprehensive technology

Making Informed Decisions About Tumor Tissue Use

Following surgery, a sample of tumor tissue will usually be sent for molecular profiling, while the remaining portion may be frozen and banked for future testing. This stored tissue can play a vital role in:

• Clinical trial enrollment: Many research studies require molecular testing to determine eligibility. Having preserved tissue available can help assess whether a patient qualifies for an emerging therapy without needing an additional biopsy
• Advanced genetic testing: As research advances, new biomarkers and treatment targets continue to be identified. Future testing on banked tissue can reveal additional insights that may influence treatment decisions
• Personalized treatment planning: If a tumor recurs, molecular characteristics may change over time. Retesting stored tissue can provide a comparison point to track tumor evolution and refine treatment strategies

Since molecular profiling is not always an automatic part of care, patients should advocate for themselves by discussing testing options with their doctor. Identified mutations or biomarkers could significantly expand treatment possibilities, including eligibility for targeted therapies and clinical trials. Companies such as Foundation Medicine¹⁷ and Caris Life Sciences¹⁸ are 2 providers of molecular testing that offer financial assistance options to patients. Understanding how tumor tissue will be used, stored, and accessed can help ensure that valuable samples remain available for future treatment opportunities in precision medicine.

When Should You Consider Molecular Profiling?

Molecular profiling is most impactful:

1. At initial diagnosis: Helps confirm the tumor type and guide initial treatment planning
2. Before considering clinical trials: Ensures eligibility for trials targeting specific mutations or pathways
3. At recurrence: Provides insights into how the tumor has evolved and identifies potential new treatment targets

The Patient’s Role in Molecular Profiling

Patients and caregivers should discuss molecular profiling with their healthcare team early in the diagnostic process. Once tumor tissue is sent for testing, results can take 2 to 3 weeks to return, creating a potential barrier to initiating treatment. Patients should speak with their healthcare team to learn how molecular profiling results can impact treatment decisions today and in the future. Questions to ask include:

• “What molecular tests are available for my type of tumor?”
  • – O6-methylguanine-DNA methyltransferase promoter methylation status and isocitrate dehydrogenase 1 and 2 mutation analysis are common
• “Are there specific biomarkers or mutations we should test for?”
• “How will the results of these tests influence my treatment options?”

Your healthcare provider can guide you on the availability of molecular testing, and organizations like the Brain Tumor Network can help connect you with labs and specialists offering these services.

Molecular profiling has become an essential tool in brain tumor care, empowering patients and their medical teams to make more informed, personalized treatment decisions. By understanding the genetic and molecular makeup of your tumor, you gain critical insights into its behavior and potential sensitivity to advanced therapies, paving the way for hope and innovation in your care journey.

Click Here for Part IV: The Importance of Palliative Care