Colorectal cancer: Application of selected liquid biopsy markers

<b>Introduction:</b> Colorectal cancer (CRC) remains one of the leading causes of cancer-related morbidity and mortality worldwide, creating a need for continuous search for innovative diagnostic and disease monitoring methods. Traditional techniques, although effective, are highly invasive and may be associated with risks for patients, which prompts the development of less invasive alternatives. One such method is liquid biopsy - a technique for analyzing circulating biomarkers in body fluids.<b>Aim:</b> This paper describes the use of liquid biopsy in both the diagnosis and treatment monitoring of CRC. The article discusses three major classes of biomarkers used in this method: circulating tumor DNA (ctDNA), circulating tumor cells (CTC), and exosomes. Particular attention is paid to their role in cancer detection and monitoring of treatment response.<b>Discussion:</b> The accuracy and invasiveness of liquid biopsy biomarkers are compared with traditional biopsy techniques. It is emphasized that liquid biopsies can provide real-time insight into tumor dynamics while minimizing patient discomfort. The clinical applications of these biomarkers are discussed, focusing on their utility in early disease detection, prognostication of tumor outcome, and development of personalized therapeutic strategies. Particular emphasis is placed on their transformative potential in improving treatment outcomes for patients with colorectal cancer.<b>Conclusions:</b> Liquid biopsies are a key element in the evolving landscape of oncology care. Their development and use have the potential to significantly improve patients' quality of life and the effectiveness of cancer treatment.