Tumor samples showed higher levels of gene expression than healthy controls: in detail, the median expression values of the three genes in the study population compared to the control group were 3.41 (95% Confidence Interval [CI], 0.27–19.20) for ERCC1, 5.89 (95% CI, 0.19–18.84) for ERCC2 and 9.24 (95% CI, 2.12–23.17) for ERCC5, respectively (Fig. 1A). Here, ERCC1 is linked to neoplasm.