The PRESSING study (Primary Resistance in RAS and BRAF Wild-Type Metastatic Colorectal Cancer Patients Treated with Anti-EGFR Monoclonal Antibodies) was a case–control investigation aimed at elucidating the role of negative hyperselection in optimizing patient selection for first-line anti-EGFR therapy in mCRC. Here, EGFR is linked to colorectal cancer.