Fig. 1. Leucine-rich repeat kinase 2 (LRRK2) is highly expressed in glioblastoma (GBM) and GBM stem cells. (A) LRRK2 staining for various brain tumor types, including oligodendroglioma, astrocytoma, and GBM. GBM showed higher LRRK2 expression than less malignant tumors like oligodendroglioma and astrocytoma. Scale bar=50 μm. (B, C) Kaplan–Meier survival plots for all glioma patients and GBM patients with high and low LRRK2 expression. Patients with high LRRK2 expression had shorter survivals, as demonstrated in the tissue microarray (TMA) data of all 161 glioma and 101 GBM patients. (D) Kaplan–Meier survival plots for all glioma patients with high and low LRRK2 expression. Data were obtained from the REMBRANDT of the National Cancer Institute (log-rank test). High LRRK2 expression in 165 of 329 glioma cases from the REMBRANDT database indicated poor prognosis. (E, F) Upon serum-induced differentiation of 0317 and 448T patient-derived cancer cells, a decrease in phospho-LRRK2 (pLRRK2) and total LRRK2 levels was noted, along with reduced cancer stemness factors (CD133, NESTIN, OLIG2, SOX2), while the differentiation marker glial fibrillary acidic protein (GFAP) increased.