A striking example of the tight relationship between sequence and function is observed in high-grade glioma patients, where lowered adenosine-to-inosine editing of a single nucleotide in miR-376a-5p leads to loss of AMFR protein repression and increased inhibition of RAP2A, which contributes to a more aggressive disease and correlates with reduced patient survival (13). Here, AMFR is linked to central nervous system cancer.