In contrast to mouse development where the loss of a single CTCF motif—if oriented towards an active enhancer—was sufficient to activate ectopic FGF expression, in human GIST cell lines, disruption of all four CTCF motifs found in its cluster is required for induction of FGF3 by ANO1 (Kim et al., 2024). Here, FGF3 is linked to gastrointestinal stromal tumor.