Interestingly, we found that after AdoMet treatment, p21 content increased in U343MG and most markedly in U87MG cells, while it became downregulated in U251MG cells, a GBM cell line harboring a TP53 gene mutation [40], suggesting that AdoMet-induced cell cycle arrest in U251MG cells probably involve a p53/p21-independent process. Here, TP53 is linked to glioblastoma.