ABCG1 and glioblastoma: Given the correlation between ABCG1 expression and overall survival in patients with mesenchymal subtype glioblastoma, we sought to determine whether ABCG1 might be important for NPcis glioma growth using lentivirus-mediated shRNA knockdown in two independently-generated NPcis high-grade glioma cell lines (K1861 and K4622; [22]).