NF1 and glioblastoma: In patients with GBM, elevated SHC1 expression was associated with single nucleotide variation (SNV) of NF1 and loss of 17p13.1; whereas decreased SHC1 expression was correlated with SPTA1 mutation, loss of 14q24.2 and 18q22.3, and gain of 2q14.1 (Fig. 5A).