GPC1 and breast angiosarcoma: Cui et al. (32) found significantly lower expression of the GPC1 gene in BECs from children with BA than in normal controls and determined that glypican 1, a heparan sulfate proteoglycan encoded by the GPC1 gene, could regulate Shh signaling, suggesting that the Shh signaling pathway may be important in liver fibrogenesis in BA.