HRH4 and colorectal carcinoma: The lack of functional H4R expression—regulated either on the level of transcription (Caco-2, HT-29) or of translation (HCT116)—may be explained by the colorectal carcinoma origin of the cell lines, in which a reduced H4R expression has already been demonstrated (Boer et al. 2008; Fang et al. 2011).