Tumor Microenvironment before and after Chemoradiation in Locally Advanced Rectal Cancer: Beyond PD-L1

Area of Science:

• Oncology
• Immunology
• Cancer Research

Background:

• Neoadjuvant concurrent chemoradiation therapy (cCRT) is standard for locally advanced rectal cancer.
• The tumor microenvironment (TME) influences tumor progression and treatment response.
• Understanding TME biomarker changes after cCRT is crucial for optimizing rectal cancer treatment.

Purpose of the Study:

• To evaluate alterations in TME biomarkers following neoadjuvant cCRT in rectal cancer patients.
• To identify specific biomarkers that change significantly after treatment.

Main Methods:

• Archival tissue from 41 rectal cancer patients treated with neoadjuvant cCRT was analyzed.
• Pre- and post-treatment biopsies were assessed for biomarkers including PD-L1, CD8+ T-cells, CXCL9, TIM-3, IDO-1, IFN-G, IL17RE, LAG-3, and OX40.

Main Results:

• Significant upregulation of CD8, IL17RE, LAG3, and OX40 was observed post-cCRT.
• A trend towards upregulation was noted for PD-L1, CXCL9, TIM-3, IDO-1, and IFN-G, though not statistically significant.

Conclusions:

• Neoadjuvant cCRT induces significant changes in specific TME biomarkers in rectal cancer.
• Upregulated biomarkers may serve as targets for novel therapeutic strategies to enhance treatment response and patient outcomes.