Objective:

To discuss the role of the tumor immune microenvironment in influencing glioblastoma (GBM) cell-state transitions and the implications for treatment resistance.

Approach:

• Cell-State Framework: Defines cell-state terminology used in single-cell studies, including NPC-like, OPC-like, AC-like, MES-like, stem-like, and stress-adapted states.
• Immune Niche Influence: Examines how the immune microenvironment affects GBM cell-state transitions and contributes to tumor heterogeneity.
• Therapeutic Challenges: Highlights the complexities of therapy-induced adaptive reprogramming in GBM cells leading to treatment resistance.

Key Findings:

• GBM exhibits profound heterogeneity and resistance to therapy, influenced by dynamic interactions with the tumor microenvironment.
• Tumor-associated macrophages and microglia play significant roles in shaping aggressive phenotypes and maintaining immunosuppressive environments.
• GBM cells can transition among various states under immune, hypoxic, and therapeutic pressures, complicating treatment outcomes.

Interpretation:

Understanding the reciprocal relationship between GBM cell plasticity and the immune niche may reveal new therapeutic vulnerabilities.

Limitations:

• The review focuses primarily on GBM and may not generalize to other gliomas.
• The complexity of the immune microenvironment and its influence on tumor behavior may not be fully captured.

Conclusion:

Durable control of GBM may require combinatorial strategies targeting both tumor cell plasticity and the immune niche.