The goal of this observational study is to validate and evaluate the clinical feasibility of using a 3-D cell culture model for CTCs isolation/purification and their cell number expansion in cancer patient with transitional cell carcinoma and patient without cancer. This project first aims to study the clinical feasibility of utilizing a 3-D cell culture model for the isolation/purification of all possible CTCs in a blood sample in a label-free, viable, and high-purity manner. Through 3-D CTC culture, moreover, the cell number of CTCs can be adequately expanded. All these advantageous features are beyond what is currently possible by using the existing methods. In addition, the harvest of CTCs with above features is found valuable for the subsequent academic researches or clinical studies (e.g. molecular mechanisms underlying cancer metastasis, cancer-related gene mutation, biomarker discovery, and particularly CTCs-based chemotherapy drug testing). These could both facilitate and accelerate scientists to develop new therapeutic solutions for future cancer care.