The Immune Checkpoint Molecule CD200 Is Associated with Tumor Grading and Metastasis in Bladder Cancer.

ABSTRACT

BACKGROUND: We examined the expression of CD200, a ligand of immune tolerance, in transitional cell carcinoma of the human bladder (TCC). MATERIALS AND METHODS: CD200 was analyzed by immunohistochemistry (IHC) in 90 patients with suspected TCC lesions of the bladder. Expression of CD200 was exemplarily validated by quantitative reverse transcription polymerase chain reaction and western blot analysis. RESULTS: CD200 was detectable at mRNA and protein levels in TCC homogenate and TCC cell lines (T24, UMUC3). TCC tissues showed significantly higher CD200 expression (p<0.005) than normal bladder tissues. CD200 signals were also higher in metastasized compared to localized TCC (p<0.05). CD200 was significantly correlated to tumor grading (p<0.001) and was strongest in the subgroup with high-grade G2 TCC (vs. low-grade G2 p<0.05). CONCLUSION: This is the first report of CD200 expression in patients with TCC. The significant correlation between CD200 expression and tumor grading may suggest CD200 as a potential target and marker for immunotherapeutic approaches.