In this regard, recently, our group reported that the selective COX-2 inhibitor, NS398, counteracted chemoresistance to TMZ, used at high concentrations (200 μM) for 72 h, in resistant GBM cell line (T98G) abrogating TMZ-induced COX-2 upregulation and COX-2-dependent pathways involved in TMZ-resistance (8). This evidence concerns the gene PTGS2 and glioblastoma.