Resumen
Circulating tumor cells are cancer cells that detach from the primary tumor and enter the bloodstream. These cancer cells in the blood stream eventually result in secondary tumor growth referred to as metastasis. Research on circulating tumor cells is crucial because they can provide valuable insights into cancer progression and treatment response that enhances the patient outcomes. Findings from circulating-tumor-cell-based research can also shed light on cancer metastasis, drug resistance, and tumor evolution, ultimately benefiting the research community by advancing our understanding of cancer biology and guiding the development of innovative treatments. In this review, we have attempted to consolidate the milestones in CTC-based research and their utility in understanding the biology of cancer from origin to progression.