Abstract 118P
Background
Clinical studies have shown that only 20-30% patients with respond to immune checkpoint inhibitors. Defining biomarkers that predict therapeutic effects is a crucial mandate. Currently, the effective biomarkers affecting immune checkpoint inhibitors include PD-L1, MSI, dMMR, Tumor Mutational Burden (TMB), Neoantigen, etc. The expression level of PD-L1 is still the most important indicator, and more and more attention has been paid to TMB as a biomarker in clinic use. However, the relationship between pd-l1 expression /TMB and immune cell infiltration (ICI) has not been fully studied.
Methods
FFPE tissues were collected from 272 Chinese patients with malignant tumors. Multiple immunohistochemistry (mIHC) was performed on the tumor tissue, including PD-L1, CD8, CD56, CD68, HLA-DR. Next generation sequencing (NGS) was performed among 58 patients to further measure TMB.
Results
Among 262 patients, 36% (97/272) are gastrointestinal tumors; 35% (94/272) are hepatobiliary and pancreatic tumors; 22% (61/272) are non-small cell lung cancer; 8% (20/272) are other tumor type. Our result show that infiltration of CD8 T cell (CD8+) and macrophage M1 cell (CD68+ HLA-DR+) are positive correlated with PD-L1 expression (p=0.0143,p=0.0412,respectively;17%,46/273,PD-L1 positive; 83%,226/272, PD-L1 negative). Infiltration of NK cell (CD56 Dim and bright) and macrophage M2 cell (CD68+ HLA-DR-) have none relevant with PD-L1 expression. We further explored correlation between TMB and ICI by NGS sequencing and mIHC. Infiltration of CD8 T cell and NK cell (CD56 bright) are positive correlated with TMB-H, as compared to TMB-L tumors (p=0.0279, p=0.0407, respectively; Top25%, 15/58.TMB-H; Last 75%, 43/58, TMB-L).
Conclusions
PD-L1 positive tumors may have higher infiltration of CD8 T cell and macrophage M1 cell, while TMB-H tumors may have higher infiltration of CD8 T cell and CD56 bright NK cell.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The first affiliated hospital of Nanchang university.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.