Prognostic impact of CD133 mRNA expression in 48 glioblastoma patients treated with concomitant radiochemotherapy: a prospective patient cohort at a single institution.

Cancer stem cells are thought to represent the population of tumorigenic cells responsible for tumor development. The CD133 antigen has been described as a putative stem cell marker in malignant brain tumor that could identify such a tumorigenic population in a subset of glioblastoma. To date, the correlation between CD133 expression in primary glioblastoma and patient prognosis is not clearly established. To address this question we investigated the relationship between CD133 mRNA expression and patient outcome in a glioblastoma patient cohort. The quantitative expression of CD133 stem cell antigen mRNA using real-time QRT-PCR was assessed in a cohort of 48 consecutive primary glioblastoma patients treated by chemoradiation with temozolomide. On multivariate survival analysis, high CD133 mRNA expression was a significant (P = 0.007) prognostic factor for adverse progression-free and overall survival independent of extent of resection (P = 0.012) and MGMT methylation status (P = 0.002). Patient age was also an independent prognosticator of overall survival (P = 0.037). Furthermore, according to the conjoined expression of CD133 mRNA and MGMT status, the patients were categorized into 3 groups with homogenous prognosis. These findings constitute conclusive evidence that the measurement of the mRNA expression of CD133 stem cell antigen actually impacts the survival of GBM patients.