Circulating tumor DNA (ctDNA)

Circulating tumor DNA (ctDNA) is fragmented DNA released from tumor cells into the blood, typically as a result of cell death processes such as apoptosis and necrosis, or active secretion. ctDNA is a subset of cell-free DNA (cfDNA) but is specifically tumor-derived, harboring genetic and epigenetic alterations present in the original tumor. Detection and quantification of ctDNA via "liquid biopsy" enable noninvasive cancer diagnosis, assessment of tumor burden, monitoring of minimal residual disease, and identification of acquired resistance mutations. ctDNA provides a dynamic, real-time molecular profile of the entire tumor and its metastases, offering a comprehensive assessment of tumor heterogeneity over time. Liquid biopsy with ctDNA is not a direct therapeutic target, but an analytical biomarker essential for precision oncology and personalized cancer therapy. Its main challenges include distinguishing ctDNA from normal cfDNA, low abundance in early or minimal disease, and a need for technological standardization. ctDNA is used as both a prognostic and predictive biomarker in oncology, but is not itself a receptor, enzyme, or pharmacological target.

Other names

circulating tumour DNAcirculating tumor-derived DNActDNA