Updated project metadata. Neoadjuvant chemoradiotherapy (CRT) is used in locally advanced rectal cancer when tumours threaten the circumferential resection margin. A variable response to treatment remains, notwithstanding potentially significant morbidity, and no clinically routinely used predictive biomarkers guide decision making. This experimental study aimed to identify significantly differentially expressed proteins between patients responding or not to CRT, using novel temporal proteomic profiling, and to validate any proteins of interest.