Abstract 29P
Background
Despite the achievements made in treating lung cancer during the past decades, lung cancer remains the leading carcinoma of incidence and death rates world widely. Compared to lung adenocarcinoma, the genomic features of Chinese lung squamous cell carcinoma (SQCC) have not been well established yet.
Methods
We enrolled 488 Chinese SQCC patients in this study from 2017 to 2020. All samples were subjected to next-generation sequencing assay of 14 major lung cancer-related genes, involving ALK, TP53, EGFR, PIK3CA, ERBB2, ALK, ROS1, MET, KRAS, FGFR1, KIT, PDGFRA, RET, BRAF and NRAS. 142 cases had enough tissue samples to underwent PD-L1 immunohistochemical assay. 120 patients provided additional matched blood to underwent germline mutation testing of 499 cancer-related genes.
Results
Of 488 patients with SQCC, 444 (90.98%) were proved to have at least one alteration in the 14 lung cancer-related genes. Compared with the Cancer Genome Atlas (TCGA) data base, a significant higher mutated frequency was found in EGFR (18.44% vs. 2.89%), ERBB2 (8.40% vs. 2.07%), FGFR1 (6.15% vs. 1.24%), KRAS (6.35% vs. 1.45%) and MET (5.12% vs. 1.65%) in our cohort. We also found one EZR-ROS1, one CD74-ROS1 and two EML4-ALK fusions which were therapeutically actionable fusions in our cohort. The ratio of tumor proportion score (TPS) levels of < 1%, 1-49% and ≥50% in PD-L1 immunohistochemical assay was 38.73%, 40.85% and 20.42%, respectively. High PD-L1 expression (TPS≥50%) was associated with a higher frequency of genomic alteration in KRAS gene (24.14% vs. 3.64%, p=0.0064), compared with negative expressed cases (TPS< 1%). Five patients (4.17%) with six pathogenic or likely pathogenic germline variants were identified in our cohort, and all variants were related to a dysfunction in DNA repair pathway, including BRCA2, FANCL, PALB2, MUTYH and MRE11A.
Conclusions
Our study identified a unique genomic feature of Chinese SQCC patients by next-generation sequencing and provided new insights on the relationship between driver genes and PD-L1 expression.
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.