To further stress the potency of the cytokine co-treatment in inducing overt fibrosis, as compared to single treatment, IBD PDOs were exposed to TNF-α or TGF-β1 alone as well as to co-treatment with cytokines and IL1B, SNAI2, ACTA2, COL4A1, SERPINE1 and FN1 were analyzed by RT-qPCR. The gene discussed is COL4A1; the disease is inflammatory bowel disease.