BMP4 and glioma: On the other hand, HIF1α has been reported to directly upregulate BMP4 expression in various types of cells and indirectly stabilize NOTCH1 protein and activate NOTCH1-HES1 signaling in human glioma stem-like cells and T lymphocytes (Wu and Paulson, 2010; Zou et al., 2013; Wang et al., 2015; Pramono et al., 2016; Man et al., 2018).