ALDH1A1 and glioblastoma: In addition, ALDH1A1 was the dominant subtype in the classical subtype of GBM, with 84.6% of the classical samples (n = 13) exhibiting high ALDH1A1 expression, while the ALDH1A1-positive rates were 12.5% and 21.7% in the proneural (PN) subtype (n = 36) and the other 2 subtypes (neural and mesenchymal (Mes)), respectively.113