Despite their significance, the study of CTCs faces several challenges. One of the main difficulties is the rarity of CTCs in the bloodstream, making their detection and isolation technically demanding. Additionally, CTCs exhibit considerable heterogeneity, meaning that they can vary greatly in their genetic and phenotypic characteristics, complicating their analysis and classification. Lastly, distinguishing CTCs from normal blood cells without losing viable cells during the isolation process remains a critical hurdle.
