TOP2A and glioblastoma: Similarly to NMF, canonical biplot confirmed the low contribution of TOP2A and XIST to the DA + AA cluster (and SFRP2 to the GBM cluster), which was due to the fact that some AA samples had similar expression levels for both genes to those observed among GBM (or to the DA + AA cluster, in case of SFRP2) (Fig. 2B).