However, CTCs are a very heterogeneous population, and identifying CTC subsets such as tumour stem cells with high metastatic potential is a difficult effort, but is critical for tumour diagnosis and management.[82] CTCs with increased metastatic potential, such as CD24+ and CD133+ CTCs, have been discovered in live animals with the use of quantum dots, and may disclose detailed mechanisms of metastasis, such as tumour cell extravasation into blood arteries.[83]. This evidence concerns the gene CD24 and neoplasm.