1. Department of Hospital Pathology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
2. Department of Urology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
3. The Cancer Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
Objective: To explore whether cultured CTC from bladder-cancer patients originate from bladder cancer and share chromosomal abnormalities, by means of a fluorescence in situ hybridization (FISH) test.
Methods: A total of 15 ml of blood was collected from the patients with bladder cancer before treatment began. Isolated CTCs were divided into 5 ml for CTC enumeration and 10 ml for CTC culture. CTCs were counted by immunofluorescent staining with vimentin, cytokeratin, CD45, and DAPI antibody. CTCs were cultured using isolated CTCs in 96-well plates of Mesenchymal Stem Cell Growth Medium for 16~18 days. The resulting cultured CTCs from 20 men with bladder cancer were analyzed by Urovysion FISH.
Results: Common gains were on chromosome 3, 7, and 17 in 20 (74.1%), 14 (51.9%), and 20 (74.1%) of 27 patients, respectively. Polysomy was detected on chromosomes 3 and 7 in 9 patients (33.3%). Polysomy involving two chromosomes was observed in 16 (59.3%, chromosome 3 and 17) and 9 patients (33.3%, chromosome 7 and 17) in the same cell. Among the patients with isolated gain, 17 (63.0%) met the positive criteria for Urovysion FISH. Homozygous deletion of 9p21, 5 (18.5%) involved more than 12 cells. Among the different patient cohorts, positive results based on the Urovysion criteria were obtained in cultured CTCs derived from 19 (70.4%) patients.
Conclusion: Application of FISH Urovysion to cultured CTCs from bladder cancer could be an effective first step to confirm their origin and sharing of chromosomal abnormalities
Keywords: Circulating tumor cells, bladder cancer, FISH Technique, chromosomal abnormality