Abstract 4836
Background
Lung cancer patients with activating EGFR mutations tend to respond poorly to IO, but this is not true for all activating mutation driven lung cancers. Recent data show that patients with BRAF mutations tend to respond better to IO. Our study estimated the tumor neoantigen burden in these tumors, and the likelihood of their presentation to cytotoxic T cells by estimating their binding affinity to major histocompatibility complex (MHC).
Methods
Whole exome data for 68 patients with EGFR mutant lung adenocarcinoma and 33 with BRAF mutations were extracted from the Cancer Genome Atlas. MAFTOOLs was used to determine the tumor mutational load. Nonamers were estimated by simulating possible nonamer neoantigens from MAF files. The neoantigen (MT) and wildtype (WT) binding affinities to MHC-I were calculated using the NetMHC 4.0 server. The differential binding affinity of the neoantigens in comparison to wildtype was calculated as mean differential agretopicity index (DAI) = WT - MT. Patient survival was estimated by the Kaplan-Meier method.
Results
Patients with mutated BRAF had higher median mutational burden (445, range 165-776) than those with EGFR mutations (90.5, range 60.5-219.5, p = 0.001). The median number of simulated neoantigens was higher in the BRAF (9536.5, range 3839.5-14626.0) vs the EGFR group (1895.5, range 1148.5-4766.5, p < 0.001). Mean DAI for BRAF and EGFR patients were 1046 and 1033, respectively, p = 0.86. In the BRAF mutant group, patients with DAI < 1,000 had significantly better 5-year survival (80% vs 40%, p = 0.022) compared to patients with DAI > 1,000. No such survival benefit was identified in the EGFR mutant group (56% vs 58%, p = 0.81).
Conclusions
BRAF mutant lung cancers are characterized by higher neoantigen burden, but their neoantigen differential binding affinity to MHC-I complex was not different from EGFR mutant lung cancers. Our analysis suggests that the improved response to IO in the BRAF mutant population is due to increased quantity in neoantigen burden and not a qualitative difference in MHC-I binding. Further, DAI had a prognostic impact in the BRAF population suggesting that it may be a measure of tumor neoantigen immunogenicity.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
J. Subramanian: Advisory / Consultancy, Speaker Bureau / Expert testimony: AstraZeneca; Advisory / Consultancy: Pfizer; Advisory / Consultancy, Speaker Bureau / Expert testimony: Boehringer Ingelheim; Advisory / Consultancy, Research grant / Funding (institution): Paradigm; Speaker Bureau / Expert testimony: Lilly; Research grant / Funding (institution): Biocept. All other authors have declared no conflicts of interest.
Resources from the same session
3988 - Basal NK activity and early Treg function inhibition predicts Nivolumab responsiveness in metastatic renal cancer patients (REVOLUTION) trial.
Presenter: Sara Santagata
Session: Poster Display session 3
Resources:
Abstract
2142 - Low NK Cell Abundance Correlates with High Expression of PD-1 in CD8+ T Cells
Presenter: Moon Hee Lee
Session: Poster Display session 3
Resources:
Abstract
5501 - Tobacco smoking is associated with the immune suppressive microenvironment in head and neck squamous cell carcinoma (HNSCC)
Presenter: Christine Chung
Session: Poster Display session 3
Resources:
Abstract
5726 - Evaluation of Antibody-Dependent Cell Cytotoxicity (ADCC) in lung cancer cell lines treated with combined anti-EGFR and anti-PD-L1 therapy.
Presenter: Francesca Sparano
Session: Poster Display session 3
Resources:
Abstract
2534 - Radiomic Signatures for Identification of Tumors Sensitive to Nivolumab or Docetaxel in Squamous Non-Small Cell Lung Cancer (sqNSCLC)
Presenter: Laurent Dercle
Session: Poster Display session 3
Resources:
Abstract
3366 - Analysis of gut microbiota in advanced non-small cell lung cancer (NSCLC) patients treated with immune-checkpoints blockers
Presenter: FEIYU ZHANG
Session: Poster Display session 3
Resources:
Abstract
2089 - Pathogenesis of Myocarditis Following Treatment with Immune Checkpoint Inhibitors in a Cynomolgus Monkey Model
Presenter: Changhua Ji
Session: Poster Display session 3
Resources:
Abstract
4463 - Effects of dietary restriction in cancer patients receiving irinotecan
Presenter: Ruben Van Eerden
Session: Poster Display session 3
Resources:
Abstract
4841 - Investigating the Link between Burn Injury and Tumorigenesis
Presenter: Lucy Barrett
Session: Poster Display session 3
Resources:
Abstract
4619 - Prognostic value of the neutrophil-lymphocyte, platelet-lymphocyte and monocyte-lymphocyte ratio in male breast cancer patients
Presenter: Joanna Huszno
Session: Poster Display session 3
Resources:
Abstract