EGFR and neoplasm: Finally, the authors know that several tissue or serum molecular biomarkers, such as research on circulating tumor cells, research on specific gene expression profiles, expression of proteins such as the epidermal growth factor receptor and vascular endothelial growth factor, research on mutations and DNA mutilations, among others, have been widely studied in terms of their ability to predict prognosis and response to chemoradiotherapy treatment, although they were not considered in the current study due to the limited availability in this service.