GPC2 and gastrointestinal stromal tumor: In contrast, 29 genes were more than 2-fold decreased in GIST as compared to ICC, including SHH, IHH, GAS1, FKBP8, SUFU, and GLI3. Overall, the 7 most under-expressed (>8-fold) genes in GIST relative to ICC were ZIC1 (Zic family member 1), FGFR3 (fibroblast growth factor receptor 3), GPC2 (glypican 2), SHH, FGF9 (fibroblast growth factor 9), SFRP1 (secreted frizzled-related protein 1), and NKX6-1 (NK6 homeobox 1).