1280P - Comprehensive characterization of human lung squamous cell carcinoma identifies high TFRC expression as a mark of poorly immunogenic tumours

Background

Lung squamous cell carcinoma (LUSC) is an aggressive tumour that accounts for 30% of all lung cancers with a 5-year survival rate of around 30%. The accumulation of CNVs and mutations on tumour suppressor genes explain the lack of directed therapies. Combination with immunotherapy in LUSC shows better efficacy than chemotherapy alone, but responses are below 50% after biomarker-based patient selection. Since tumour immunity determines the efficacy of immunotherapy, a better characterization of the immune landscape in LUSC could improve patient selection and treatment success. Altogether, this highlights the importance of identifying more precise molecular markers, as well as novel targets for LUSC treatment.

Methods

98 early-stage patient samples Multiparametric study: Clinical annotations, targeted DNA and RNA sequencing. Immunohistochemistry (IHC): CD8, CD4, CD20, TFRC, ferritin. Total iron staining (Turnbull Blue and Tirmann-Schmelzer methods). In vitro assays in LUSC cell lines CRISPR-KO and lentiviral-mediated overexpression of TFRC. Crystal violet. Western blot. Indirect immunofluorescence.

Results

The multiparametric analysis identified an amplification on TFRC gene in 30% of the patients associated to a transcriptional upregulation of tumour progression genes and a downregulation of immune-related genes. The reduction of immune cell infiltration according to IHC results further supported the immune-cold profile of these tumours. TFRC genomic amplification in tumour cells was translated into higher mRNA and protein levels in patient samples, which finally led to an accumulation of iron, suggesting a functional role of this copy number gain. In addition, iron positive samples showed decreased immune cell infiltration, especially CD8 T cells. While in vitro cell growth of LUSC cell lines was not affected by TFRC overexpression, it was significantly reduced in TFRC knockout cells.

Conclusions

Alterations in TFRC in LUSC patients have functional impact in both the tumour and the immune cells, pointing at TFRC as a potential biomarker of tumour immunity and a therapeutic target.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Instituto de Salud Carlos III (ISCIII).

Disclosure

J. Zugazagoitia: Financial Interests, Personal, Advisory Role: AstraZeneca Spain, Bristol Myers Squibb, Pfizer, Roche/Genentech, NanoString Technologies, Guardant Health, Novartis; Financial Interests, Personal, Speaker’s Bureau: MSD Oncology, Bristol Myers Squibb, Pfizer, Roche, AstraZeneca, NanoString, Guardant Health; Financial Interests, Institutional, Research Funding: AstraZeneca, Roche/Genentech, Bristol Myers Squibb. E. Conde Gallego: Financial Interests, Research Grant: Lilly, Roche, Thermo Fisher; Financial Interests, Personal, Speaker, Consultant, Advisor: AstraZeneca, BMS, Lilly, MSD, Pfizer, Roche, Takeda. E.M. Garrido-Martin: Financial Interests, Personal, Advisory Board: Bristol Myers Squibb; Financial Interests, Personal, Speaker’s Bureau: Illumina Inc, Pfizer; Financial Interests, Personal, Member of Board of Directors: PharmaMar. L. Paz-Ares: Financial Interests, Personal, Advisory Board, Speaker fees: Roche, MSD, BMS, AZ, Lilly, PharmaMar, BeiGene, Daiichi, Medscape, PER; Financial Interests, Personal, Advisory Board: Merck Serono, Pfizer, Bayer, Amgen, Janssen, GSK, Novartis, Takeda, Sanofi, Mirati; Financial Interests, Personal, Other, Board member: Genomica, Altum sequencing; Financial Interests, Institutional, Coordinating PI: Daiichi Sankyo, AstraZeneca, Merck Sharp & Dohme Corp, BMS, Janssen-Cilag International NV, Novartis, Roche, Sanofi, Tesaro, Alkermes, Lilly, Takeda, Pfizer, PharmaMar; Financial Interests, Personal, Coordinating PI: Amgen; Financial Interests, Other, Member: AACR, ASCO, ESMO; Financial Interests, Other, Foundation Board Member: AECC; Financial Interests, Other, President, ASEICA (Spanish Association of Cancer Research): ASEICA; Financial Interests, Other, Foundation president: ONCOSUR; Financial Interests, Other, member: Small Lung Cancer Group. All other authors have declared no conflicts of interest.