1280P Comprehensive Characterization of Human Lung Squamous Cell Carcinoma Identifies High TFRC Expression As a Mark of Poorly Immunogenic Tumours

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. 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. 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. 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.