**4. Conclusion**

Late clinical diagnosis and chemotherapy resistance are the main factors leading to reduced chances of survival for cancer patients. To combat cancer, CTCs provide invaluable information on the status of the disease and the likely outcome of chemotherapeutic treatment. The enumeration of CTCs allows early detection of cancer, prognosis and real-time monitoring of chemotherapy treatment. The single-cell analysis of CTCs provides a wealth of genetic information that enables better understanding of the disease complexity for individual patients and provides the opportunity for the development of personalised treatment. To aid in delivering better therapeutic medicine, current technologies allow CTCs to be cultured *in vitro* for the identification of novel therapeutic targets and optimal drug dosage for individual patients. Therefore, the molecular characterisation of CTCs is important for improving the clinical outcomes in cancer patients.
