The Power of CD8+ T Cells in Cancer Treatment

Cancer treatment has seen a major shift with the introduction of immune checkpoint blockade. This method has led to significant improvements in long-term outcomes and survival rates, especially when combined with other treatments. However, not everyone benefits from these treatments. Some patients face serious side effects. This is due to the complexity of cancer, which is influenced by various factors like ligand-receptor interactions and key transcription factors. These factors create a tough environment for T cells, making immunotherapy less effective. To tackle this, the FDA has approved biomarkers like tumor mutational burden and PD-L1 expression. These help identify patients who might benefit from ICB. Yet, these biomarkers have their limits, making treatment decisions tricky. Recently, T cells, which are the main target of ICB, have shown promise as biomarkers. These cells play a crucial role in the immune response and could help predict how well a patient will respond to treatment. CD8+ T cells, in particular, have been linked to positive outcomes in many cancers. However, getting tumor tissue to study these cells is challenging. On the other hand, circulating T cell subsets are easier to access and have shown potential as predictive biomarkers. Memory and progenitor exhausted T cells are linked to better immunotherapy responses, while terminally exhausted T cells are not. Combining different biomarkers could improve predictive accuracy. For example, integrating TMB/PD-L1 expression with CD8+ T cell frequency has shown promising results. Computational models that incorporate cancer and immune signatures could further refine patient stratification, moving us closer to personalized immunotherapy. This approach could help doctors make better treatment decisions and improve patient outcomes. It's important to note that while these findings are promising, more research is needed to fully understand the role of CD8+ T cells in cancer treatment.