ALDH1 expression is correlated with pathologic grade and poor clinical outcome in patients with astrocytoma

Aldehyde dehydrogenase 1 (ALDH1), a detoxifying enzyme, is a stem-like cell marker, but its expression pattern and clinical significance in astrocytoma remain unclear. In this study, we used immunohistochemical analysis to systematically investigate the expression of ALDH1 in 76 astrocytomas of different pathological grade and seven samples of normal brain tissues. We found that ALDH1 was expressed in some of the astrocytomas but was not detected in normal brain tissues. The proportion of ALDH1-expressing cells was positively correlated with the pathological grade of the astrocytomas, but not with patient age, sex or tumor size. We also collected detailed follow-up data and analyzed the correlation of ALDH1 expression with overall survival (OS) and progression-free survival (PFS) using univariate and multivariate analysis. We found that the proportion of ALDH1-positive cells was an independent prognostic factor for PFS and OS. These results show that ALDH1 is expressed in astrocytoma, and that its expression is correlated with pathological grade and patient survival.