By Suzanne Bissonnette, MBA
Accurate assessment of immune response in cancer patients undergoing immunotherapy is essential for evaluating treatment efficacy and predicting outcomes. Two prominent biomarkers that have gained attention are CD8+ T cells and the Immunoscore. Understanding how these markers complement each other could provide more accurate monitoring methods, potentially reducing reliance on serial biopsies and imaging.
What is the Immunoscore, and How is it Obtained?
The Immunoscore is a standardized system that quantifies the density of immune cells, particularly CD8+ T cells, within the tumor core and at the invasive margin. Developed to improve traditional cancer staging methods, the Immunoscore is based on the finding that higher densities of cytotoxic T cells correlate with better clinical outcomes in cancers such as colorectal cancer. It measures immune infiltration by examining these cells in two distinct tumor regions1. To obtain an Immunoscore, a biopsy is necessary to collect tissue samples. Pathologists analyze the tissue using immunohistochemistry to detect and quantify the density of immune cells. While it is still an invasive method, the comprehensive immune profiling provided by the Immunoscore can potentially reduce the need for multiple biopsies by serving as a robust baseline for monitoring the immune response over time.
The Role of CD8+ T Cells
CD8+ T cells are crucial components of the immune system's response to cancer, targeting and killing cancer cells. Their presence within the tumor microenvironment is generally linked to a favorable prognosis in various cancers, including melanoma, non-small cell lung cancer, and colorectal cancer 2. However, since CD8+ T cells are also involved in responses to infections and inflammatory conditions, their presence alone may not always indicate a tumor-specific immune response. This nonspecificity can complicate the interpretation of CD8+ T cells alone as a biomarker for cancer immunotherapy efficacy.
Could the Immunoscore and CD8 ImmunoPET be complementary?
CD8 ImmunoPET is a promising non-invasive imaging technique that visualizes the distribution of CD8+ T cells throughout the body. When used in conjunction with the Immunoscore, it may offer a more holistic approach to monitoring immune activity over time. The Immunoscore provides spatially resolved, detailed immune profiling from the initial biopsy, while CD8 ImmunoPET allows for ongoing, whole-body monitoring of immune changes, potentially offering more specific insights into the effects of immunotherapy 3.
Combining these tools allows for a hybrid approach; while the Immunoscore provides detailed, spatially resolved immune profiling from a biopsy, CD8 ImmunoPET enables ongoing, whole-body monitoring of CD8+ T cell dynamics throughout the treatment course.
Could This Approach Reduce Invasive Procedures?
While the Immunoscore itself requires an initial biopsy, its detailed immune profiling may reduce the need for frequent repeat biopsies if used with serial CD8 ImmunoPET scans. The ImmunoPET technology is designed to enable clinicians to track immune changes and treatment responses with greater sensitivity, potentially reducing the frequency of invasive procedures over time 4. This combination could offer a patient-friendly alternative, improving how clinicians monitor the effectiveness of immunotherapy and adjust treatments accordingly.
Moving Towards Personalized Monitoring in Immunotherapy
Integrating multiple biomarkers is becoming increasingly essential for understanding the complexity of cancer's immune environment. The complementary use of Immunoscore and CD8 ImmunoPET aligns with the shift toward personalized oncology, where monitoring is tailored to each patient's unique cancer characteristics. While obtaining an Immunoscore still requires a biopsy, its combination with non-invasive techniques like CD8 ImmunoPET could represent a significant advance in monitoring cancer immunotherapy, providing deeper insights into immune activity and optimizing patient care.
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