Circulating tumor DNA (ctDNA) refers to small fragments of DNA shed by cancer cells into the bloodstream. It is a component of cell-free DNA (cfDNA) and can be isolated through non-invasive methods such as liquid biopsies. ctDNA reflects the genetic alterations present in tumors, including mutations, copy number changes, and structural rearrangements. It has become a valuable tool in oncology for diagnosis, prognosis, and monitoring of cancer.
Key Features of ctDNA:
- Non-Invasive Monitoring: ctDNA can be repeatedly sampled via blood tests, providing real-time insights into tumor dynamics without the need for invasive biopsies.
- Personalized Insights: It helps in detecting specific genetic mutations or alterations, allowing for tailored therapeutic strategies.
- Early Detection: ctDNA is being explored for use in detecting cancers at early stages or in cases of minimal residual disease (MRD).
- Monitoring Treatment Response: Quantitative and qualitative changes in ctDNA levels can indicate how a tumor is responding to therapy.
- Identifying Resistance Mechanisms: Mutations linked to therapy resistance can be detected, aiding in adjusting treatment plans.
Applications:
- Cancer Diagnosis: Identifying the presence of malignancy.
- Prognosis: Assessing tumor aggressiveness and patient outcomes.
- Therapeutic Guidance: Informing the selection of targeted therapies.
- Recurrence Monitoring: Detecting signs of cancer relapse after treatment.
Advances in next-generation sequencing (NGS) and other sensitive molecular techniques have significantly enhanced the utility of ctDNA in precision oncology.