Ionizing Radiation Enhances Prognostically Significant Cellular Immunity Programs in the Brain Metastasis...

Area of Science:

• Oncology
• Immunology
• Genomics

Background:

• Brain metastasis (BM) is a severe complication of cancer, often linked to impaired immune function.
• Understanding BM-associated immunosuppression is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the molecular characteristics and clinical significance of immunosuppression in brain metastasis.
• To analyze the impact of radiation therapy on the immune microenvironment in BM.

Main Methods:

• Integrated molecular profiling (T-cell receptor sequencing, RNA sequencing) of patient-derived breast and lung cancer BM tissues.
• Histopathological scoring of tumor-infiltrating lymphocytes (TILs) and correlation with clinical outcomes.
• Analysis of immune responses in a clinical trial of stereotactic radiosurgery/radiotherapy (SRS/SRT) for BM.

Main Results:

• Higher TIL infiltration and T-cell receptor (TCR) diversity were associated with favorable prognoses in breast and lung cancer BM.
• SRS/SRT treatment increased TCR diversity and antigen processing/presentation signatures in the BM microenvironment.
• Radiation therapy reactivated suppressed immune signatures and upregulated pathways linked to better outcomes in breast cancer BM.

Conclusions:

• Elevated TCR diversity in BM is a marker of favorable prognosis and indicates potential therapeutic targets.
• Radiation therapy enhances T-cell-mediated immunity in BM by increasing TCR diversity and antigen presentation.
• Further research into radiation-induced immunomodulation in BM, possibly combined with immune checkpoint inhibitors, is warranted.