DNA repair gene expression level in peripheral blood and tumour tissue from non-small cell lung cancer and head and neck squamous cell cancer patients

► Non-invasive methods to detect prognostic and/or predictive biomarkers are needed. ► DNA repair gene expression in tumour tissue can predict response to chemotherapy. ► We tested the correlation between gene expression levels in tumour tissue and blood. ► Some DNA repair gene expression levels in blood and tumour significantly correlate. ► Blood can be a tumour tissue proxy to test gene expression as prognostic biomarker.