ASCL1 and poikiloderma with neutropenia: Most remarkably, we tested several GBM samples that were previously classified based on both transcriptional profiling and immunohistochemistry (IHC) for subgroup-restricted markers and found that ASCL1 protein was specifically retrieved in human PN samples (n = 6 and n = 10 patients for PN and MES, respectively) (Fig. 1g).