Among Notch ligands, Jag1 is a well-characterized main regulator of liver development and regeneration.24 Jag1 has been implicated in the development of multiple tumour types.24, 25 For instance, Jag1 expression has been found to be upregulated and its levels inversely associated with patient's survival in breast, colon and cervical cancers.26, 27, 28 Also, silencing of Jag1 in human prostate cancer cells decreases cell invasion and in vivo tumour growth.29 However, the functional contribution of Jag1 in ICC development has not been studied to date. The gene discussed is JAG1; the disease is prostate carcinoma.