In the first paper published on the derivation of TB-ORGs Haider et al. used EGF, the TGF-β signalling inhibitor A83-01, the BMP signalling inhibitor Noggin, and the activators of Wnt signalling, R-spondin, CHIR99021 and prostaglandin E2, substances which have been utilized to successfully establish epithelial organoids from other human tissues [34, 174]. Here, RSPO1 is linked to tuberculosis.