Abstract 1743
Background
Antigen recognition by MHC class I molecules is a key step for the initiation of the immune response. We hypothesized that expression of these molecules could be a marker of immune activated breast cancers.
Methods
We used data from KM Plotter to develop an exploratory cohort and then utilized information from Cancer Genome Atlas (TCGA) and METABRIC to create two validation cohorts. Raw data were re-processed and analyzed using plyr R and Bioconductor. Definition of molecular subtypes as well as identification of mutations was performed using RNAseq from TCGA. We used NetMHC 4.0 epitope-HLA to predict binding to MHC I molecules. Cox proportional hazards regression was computed to correlate gene expression and survival outcome. Multiple genes were combined into a signature by using their mean expression.
Results
There was a weak but positive correlation between mutational burden and the expression of most MHC class I molecules. In the exploratory cohort, expression of HLA-A and HLA-B was associated with favorable relapse free survival (RFS) and overall survival (OS) in the basal-like subgroup. This was confirmed in the METABRIC dataset (OS HLA-A, HR: 0.59, CI 0.42-0.82; p = 0.002; HLA-B, HR: 0.60, CI 0.44-0.82; p = 0.001); and in the TCGA dataset (OS HLA-A, HR: 0.34, CI 0.16-0.75; p = 0.005; HLA-B, HR: 0.21, CI 0.01-0.71; p = 0.005). Expression of HLA-A and HLA-B was associated with biomarkers of T cell activation (GZMA, GZMB and PRF1) and improved the predictive capacity of known immunologic signatures (IFN gamma signature, expanded immune gene signature and Cytotoxic T lymphocyte). Several neopeptides expressed in breast cancer were also identified including FUK, SNAPC3, GC, ANO8, DOT1L, HIST1H3F, MYBPH, STX2, FRMD6, CPSF1, or SMTN, among others.
Conclusions
Expression of HLA-A and B is associated with T cell activation and identifies immune activated, basal-like breast cancers with favorable prognosis.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Instituto de Salud Carlos III (PI16/01121), ACEPAIN; Diputación de Albacete, CIBERONC, CRIS Cancer Foundation, scientific foundation of the AECC, implementation research program of the UCLM Spanish System of Science, Technology and Innovation-Secti (co-funded by the European Commission/FSE funds).
Disclosure
A. Ocaña: Research grant / Funding (institution): Entrechem; Travel / Accommodation / Expenses: Merck. All other authors have declared no conflicts of interest.
Resources from the same session
4489 - A Window of Opportunity Trial of Atorvastatin Targeting p53 Mutant Malignancies
Presenter: Joaquina Baranda
Session: Poster Display session 3
Resources:
Abstract
1945 - Randomized Phase II Study of Trabectedin/Olaparib Compared to Physician’s Choice in Subjects with Previously Treated Advanced or Recurrent Solid Tumors Harboring DNA Repair Deficiencies.
Presenter: Christoph Heilig
Session: Poster Display session 3
Resources:
Abstract
3021 - Homogenisation of Leftover Surgical Tissue across multiple cancer types: a Feasibility Study (HoLST-F)
Presenter: Lavinia Spain
Session: Poster Display session 3
Resources:
Abstract
2882 - Safety, efficacy, and immune effects of intratumoral tilsotolimod in patients with refractory solid tumors: updated results from ILLUMINATE-101
Presenter: Hani Babiker
Session: Poster Display session 3
Resources:
Abstract
1950 - Phase 1 Dose Escalation of MSC-1, a humanized anti-LIF monoclonal antibody, in patients (pts) with advanced solid tumors: Updated results
Presenter: Erkut Borazanci
Session: Poster Display session 3
Resources:
Abstract
2391 - A phase 1 study of Sym021, an anti-PD-1 antibody (Ab), alone and in combination with Sym022 (anti-LAG-3) or Sym023 (anti-TIM-3)
Presenter: Anna Spreafico
Session: Poster Display session 3
Resources:
Abstract
5692 - FPA150 (B7-H4 antibody) Phase 1 Update in Advanced Solid Tumors: Monotherapy and in Combination with Pembrolizumab
Presenter: Zev Wainberg
Session: Poster Display session 3
Resources:
Abstract
2416 - MG1124, a novel CEACAM1-targeted monoclonal antibody, has therapeutic potential as a combination partner of PD-1 inhibitors in NSCLC patients
Presenter: Eun Hee Lee
Session: Poster Display session 3
Resources:
Abstract
2661 - Tumor stroma targeting and modulation by OMTX705 ADC, a novel and potent immunotherapeutic treatment of solid tumors.
Presenter: Myriam Fabre
Session: Poster Display session 3
Resources:
Abstract
3681 - Durvalumab + monalizumab, mFOLFOX6, and bevacizumab in patients (pts) with metastatic microsatellite-stable colorectal cancer (MSS-CRC)
Presenter: May Cho
Session: Poster Display session 3
Resources:
Abstract