Table 1.

Enrichment methods for CTCs in biological fluids.

Methods	Benefits	Pitfalls
Density-gradient centrifugation	Simple, fast process	Poor sensitivity (potential loss of tumor cells)
Filtration	Isolation by size, do not require cell lysis	Low number of collected CTCs
Immunomagnetic selection	Enhanced sensitivity, enhanced specificity, intact cells	Costly and time-consuming process, false positives, false negatives