CXCL8 and Cowden disease: To identify whether the miR-29b/IL-6/IL-8 axis affects the collagen genes previously shown to be down-regulated in fibroblasts from CD patients by miR-29b (Nijhuis et al. 2014), mRNA expression of both COL1A2 and COL3A1 was measured following stimulation with IL-6 or IL-8 (10 ng/ml).