FGF2 and neoplasm: Our results showed that although U118–RFP and HUVEC–GFP weakly secreted bFGF, their bFGF secretability was remarkably enhanced when both types of cells were cocultured in hydrogel microfibers possibly because when tumor and endothelial cells were cocultured in a 3D microenvironment, the paracrine and autocrine pathways of the cells stimulated the ability of both cells to secrete vascular growth factors (Zhou et al., 2021).