169P - Analysis of tumor immune microenvironment with mIHC in Chinese non-small cell lung cancer

Background

Anti-PD1/PDL1 therapy has been established as standard care for first- and second-line treatment patients with advanced Non-Small Cell Lung Cancer (NSCLC), and tumor immune microenvironment (TIME) is elemental to predict how patients respond to immunotherapy and their prognosis. The multiplex immunohistochemistry (mIHC) provides the possibility to deeper characterize the infiltrating immune cells and classify patients more precisely.

Methods

FFPE tissues were collected from 231 NSCLC patients, and TIME tests were performed using a validated commercial mIHC assay. Images were analyzed using the APTIME software by 3D Medicines. Tumor parenchyma and stroma were differentiated by CK staining.

Results

In our study, patients with squamous cell carcinomas exhibited a higher stromal density of CD68+CD163+ M2 macrophage cells (p= 0.020), PD-L1+ cells (P= 0.029), compared to those with adenocarcinoma. While patients with adenocarcinoma showed a higher stromal density of CD3+CD4+ cells (P=0.046). There were no significant differences in immune cell infiltration between younger (age<=60) and older (age>60) groups. In addition to mIHC, 171 samples underwent next-generation sequencing (NGS). Among 103 patients with available tumor mutation burden (TMB) results, patients with TMB-H (≥10 muts/Mb) exhibited higher median density of stromal CD20+ B cells (P=0.009) and CD3+ T cells (p=0.004). Additionally, patients carrying EGFR mutations (n =159) had lower infiltration of T cells than those with wild-type EGFR (N=162), including tumoral CD3+ T cells (P<0.001), CD 8+T cells (P<0.001), PD-1+CD8+(P<0.001), as well as tumoral PD-1+ cells (p=0.006) and PD-L1+CD68+ cells (p=0.024). Patients carrying MET mutations (n =3) had a higher level of tumoral CD3+ T cells than those with wild-type (P<0.008). Patients carrying BRAF mutations (n=5) had a higher level of tumoral CD56bright NK cells than those with wild-type (n=166) (P=0.024). There were no significant differences observed between KRAS mutant (n=20) and wild-type (n=151) groups.

Conclusions

Together, these data outlined the immune infiltration associations with clinical and molecular features in NSCLC. Tumor immune microenvironment might serve as a promising biomarker for immunotherapy.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.