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PD-L1 Expression in Paired Samples of Rectal Cancer
by
, , , , , , , , ,
Mina Coussement
1,
Roberta Fazio
1,
Alessandro Audisio
1,
Reem El Khoury
1,
Fatima-Zahra Abbassi
1,
Irene Assaf
1,
Chiara Conti
1,
Chiara Gallio
1,
Nada Benhima
1,
Giacomo Bregni
1,
Paraskevas Gkolfakis
1,
Valentina Spagnolo
1,
Geraldine Anthoine
1,
Gabriel Liberale
1,
Luigi Moretti
1,
Philippe Martinive
1,
Alain Hendlisz
1,
Pieter Demetter
2,3 and
Francesco Sclafani
1,* 1
Institut Jules Bordet, Université Libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (HUB), 1070 Brussels, Belgium
2
Cerba Path, Division CMP, 1070 Brussels, Belgium
3
Laboratory for Experimental Gastroenterology, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
*
Author to whom correspondence should be addressed.
Cancers 2024, 16(14), 2606; https://doi.org/10.3390/cancers16142606 (registering DOI)
Submission received: 16 June 2024
/
Revised: 17 July 2024
/
Accepted: 18 July 2024
/
Published: 21 July 2024
(This article belongs to the Special Issue Current Status, Challenges and Future of Precision Medicine for Colorectal Cancer)
Simple Summary
There is an increased interest for the investigation of immunotherapy and immune-related biomarkers in rectal cancer. We retrospectively analysed the expression of the programmed death-ligand 1 (PD-L1) in diagnostic biopsies and resection samples from a cohort of 83 rectal cancer patients. Using three different methods for the analysis of PD-L1, we found that the expression of this biomarker was lower in resection samples than in diagnostic biopsies. Also, we observed that higher levels of PD-L1 in resection specimens were associated with better survival outcomes. The results of our study contribute to the knowledge of PD-L1 expression in rectal cancer, having the potential to inform the design of future immunotherapy trials in this setting.
Abstract
Immune checkpoint inhibitors and immune-related biomarkers are increasingly investigated in rectal cancer (RC). We retrospectively analysed PD-L1 expression in diagnostic biopsy and resection samples from RC patients treated at our centre between 2000 and 2020. PD-L1 immunostaining (22C3 clone) was evaluated according to tumour proportion (TPS), immune cell (ICS), and the combined positive score (CPS). Eighty-three patients were included. At diagnosis, PD-L1 expression ≥1%/≥5% was observed in 15.4%/0%, 80.7%/37.4%, and 69.2%/25.6% of patients based on TPS, ICS, and CPS, respectively. At surgery, the respective figures were 4.6%/1.5%, 60.2%/32.5%, and 50.7%/26.2%. Using the 1% cut-off and regardless of the scoring system, PD-L1 was less expressed in surgery than biopsy samples (p ≤ 0.04). In paired specimens, PD-L1-ICS reduction was especially observed following neoadjuvant long-course (chemo)radiotherapy (p = 0.03). PD-L1-ICS of ≥5% in surgical samples (HR: 0.17; p = 0.02), and a biopsy-to-surgery increase in PD-L1-ICS (HR: 0.19; p = 0.04) was predictive for longer disease-free survival, while the PD-L1-ICS of either ≥1% (HR 0.28; p = 0.04) or ≥5% (HR 0.19; p = 0.03) in surgical samples and the biopsy-to-surgery increase in PD-L1-ICS (HR: 0.20; p = 0.04) were associated with better overall survival. Our study suggests that PD-L1 expression in RC is largely reflective of immune cell infiltration, and its presence/increase in surgical samples predicts better outcomes.
