1. Immune checkpoint status and oncogenic mutation profiling of rectal cancer after neoadjuvant chemotherapy (KSCC1301‐A2)
- Author
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Yu Miyashita, Eiji Oki, Tomohiro Kamori, Yoshito Akagi, Shinichiro Mori, Norifumi Hattori, Kazuma Kobayashi, Mototsugu Shimokawa, Yoshinao Oda, and Masaki Mori
- Subjects
immune checkpoint inhibitor ,neoadjuvant chemotherapy ,next‐generation sequencing ,rectal cancer ,tumor microenvironment ,Surgery ,RD1-811 ,Diseases of the digestive system. Gastroenterology ,RC799-869 - Abstract
Abstract Aim Immune checkpoint inhibitors (ICIs) are less effective in mismatch repair (MMR)‐proficient (pMMR) colorectal cancers (CRCs) than in MMR‐deficient CRCs. Here, we investigated changes in the tumor microenvironment after neoadjuvant chemotherapy (NAC) without radiotherapy in locally advanced rectal cancer (LARC) and the potential of ICIs as therapeutic agents for pMMR CRCs. Methods This was an ad hoc analysis of a KSCC1301 randomized phase II trial in which patients with untreated resectable LARC were randomly assigned to receive S‐1 and oxaliplatin or folinic acid, 5‐fluorouracil, and oxaliplatin as NAC. Forty‐nine patients were studied in this ad hoc analysis. As a reference cohort, we assessed 25 rectal cancer patients who underwent surgery without NAC outside the randomized trial. Immune checkpoint molecules (ICMs; PD‐1, PD‐L1, CTLA‐4, LAG3), tumor‐infiltrating lymphocytes (TILs; CD8, FOXP3), and other related proteins were evaluated by immunohistochemistry. Next‐generation sequencing (NGS) using Oncomine™ Comprehensive Assay version 3 was conducted in 23 patients. Results The expression levels of PD‐1, CTLA‐4, and LAG3 in the NAC group were significantly higher than in reference patients (p
- Published
- 2024
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