NANOG and astrocytoma (excluding glioblastoma): This study aimed to characterize the ID4 expression pattern in human astrocytomas of grades II to IV of malignancy; to correlate its expression level to that of SOX2, SOX4, OCT-4 and NANOG, along with TP53 mutational status; and to correlate the results with the clinical end-point of overall survival among GBM patients.