CXCL6 and neoplasm: Co-culturing of tumour cells and fibroblasts in 3D conditions did not result in the appearance of new cytokines; rather, the amounts of certain cytokines already upregulated in 3D mono-cultures, such as GCP-2, IL-6, amphiregulin, GRO/GRO-α, IL8, and MSP-α, were further increased (Fig. 4B).