Therefore, given the very poor 5-year survival rate of CRC patients, better diagnostic markers that can detect disease at an early stage are still a necessity.107–109 Breast cancer (BC) is the most common cancer among women globally, accounting for 12% of all new cancer cases worldwide.109–111 While Cancer antigen 153 (CA153) and CEA are the commonly used biomarkers, there remains a need for better BC diagnostic and prognostic markers for BC. Here, CEACAM5 is linked to breast cancer.