KITLG and intrahepatic cholangiocarcinoma: Cultured ICC also express soluble and membrane-bound forms of stem cell factor (SCF, the maturation and development activation ligand for KIT), whereas freshly dispersed ICC only express soluble forms of SCF at the transcriptional level, suggesting the ICC in primary gut tissue requires cell-to-cell contact with other cells producing membrane-bound SCF (e.g., smooth muscle cells) in order to develop and maintain ICC phenotype (while cultured ICC are able to maintain ICC-MY network phenotype without other cells present) [31].