Expansion of Circulating Tumor Cells (CTC), the metastatic seeds of cancer in the blood stream, holds great potential in clinical application, especially towards precision medicine. Given the relatively rare nature of CTCs, their culture remains to be a significant challenge. When developing technologies for CTC culture, there are key elements that need careful consideration, including the speed of culture, compatibility with downstream analysis, and the implementation of the technology into established clinical daily routines. Herein, we briefly discuss the implications of our recent report of an ultrathin filter for the capture and culture of circulating colon cancer cells.