APOBEC3B and inflammatory bowel disease: Transcriptomic analysis of epithelial cells and fibroblasts individually within Healthy versus IBD Chips revealed that genes which were found to be overexpressed in Crohn’s and UC (e.g., ADA2, APOBEC3B, GSPT2, CD40, ACAN, HLA-DQB1) epithelium on-chip were also expressed at higher levels compared to healthy epithelium (Extended Data Fig. 3A,B).