Clinical Report: Assessment of PD-L1 Expression in Colorectal Cancer

Overview

This study evaluated PD-L1 expression in colorectal cancer (CRC) using the ZR3 clone and its association with clinicopathological variables and survival outcomes in a Pakistani cohort.

Background

Colorectal cancer (CRC) is a leading cause of cancer incidence and mortality worldwide, with significant implications for patient management and treatment strategies. The role of PD-L1 as a biomarker in CRC remains controversial, as its expression varies widely and lacks validation for clinical use. Understanding the relationship between PD-L1 expression and established biomarkers like microsatellite instability (MSI) is crucial.

Data Highlights

Key Findings

• PD-L1 expression was detected in 71.7% of tumors using a TPS cutoff of ≥1%.
• No clinicopathological variable showed an association with binary PD-L1 status after correction for multiplicity.
• MSI-H/dMMR tumors correlated with high PD-L1 expression but not with binary positivity.
• PD-L1 status was not associated with overall survival, disease-free survival, or progression-free survival.
• Mortality was significantly associated with older age rather than PD-L1 status.

Clinical Implications

The positivity rate of PD-L1 in this cohort requires careful interpretation of assay results.

Conclusion

This study presents findings on PD-L1 expression in CRC and its association with clinicopathological variables.

Related Resources & Content

1. The ASCO Post, 2015 -- Mismatch Repair Deficiency Predicts Benefit With Pembrolizumab in Colorectal Cancer
2. Prognostic and Clinicopathological Implications of PD-L1 Expression in Colorectal Cancer: A Meta-Analytic Review
3. Mismatch Repair and Microsatellite Instability Testing for Immune Checkpoint Inhibitor Therapy: Guideline From the College of American Pathologists
4. Pembrolizumab versus chemotherapy for microsatellite instability-high or mismatch repair-deficient metastatic colorectal cancer (KEYNOTE-177)
5. Nivolumab plus ipilimumab vs chemotherapy for MSI-H/dMMR metastatic colorectal cancer
6. The ASCO Post — Mismatch Repair Deficiency Predicts Benefit With Pembrolizumab in Colorectal Cancer
7. Evaluation of Clinical Features Associated with Mismatch Repair Deficiency in Colorectal Cancer: A Retrospective Multicenter Study
8. Mismatch Repair and Microsatellite Instability Testing for Immune Checkpoint Inhibitor Therapy: Guideline From the College of American Pathologists in Collaboration With the Association for Molecular Pathology and Fight Colorectal Cancer - PubMed
9. Pembrolizumab versus chemotherapy for microsatellite instability-high or mismatch repair-deficient metastatic colorectal cancer (KEYNOTE-177): final analysis of a randomised, open-label, phase 3 study - PMC
10. Nivolumab (NIVO) plus ipilimumab (IPI) vs chemotherapy (chemo) as first-line (1L) treatment for microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC): First results of the CheckMate 8HW study. | Journal of Clinical Oncology
11. Programmed death ligand-1 (PD-L1) clone 22C3 expression in resected colorectal cancer as companion diagnostics for immune checkpoint inhibitor therapy: A comparison study and inter-rater agreement evaluation across proposed cut-offs and predictive (TPS, CPS and IC) scores - ScienceDirect