IDH1 and glioblastoma: Moreover, a recent study found that, along with TP53 and IDH1, MUC4 was one of the genes most frequently affected by single nucleotide polymorphism (SNP) in IDH-mutated (IDH-m) patients progressing towards grade 4 astrocytoma (secondary GBM; 2016 classification) suggesting the MUC4 protein involvement in gliomagenesis19.