Comment on "Expression of CD44 and the survival in glioma: a meta-analysis"

CD44 has been considered as a cancer stem cell marker in various tumors. With great enthusiasm, we read an article written by Wu et al. entitled "Expression of CD44 and the survival in glioma: a meta-analysis" published in Bioscience Reports. The authors performed meta-analyses to study the prognostic significance of CD44 in gliomas, and drew the conclusion that high expression of CD44 may predict poor survival in glioma, particularly in WHO grade II-III gliomas. However, two major defects exist in the present study, which made the meta-analysis on the prognostic significance of CD44 in all gliomas unreliable. In this commentary, we discussed the limitations and significance of the present study.