FGF2 and neoplasm: Traditional in vitro culture models, whether monolayer culture or tumor sphere culture, may take a lot of time to establish and use exogenous epidermal growth factor, basic fibroblast growth factor, and/or serum to serially pass tumor cells in a clonal expansion fashion, which is not conducive to maintaining the various cell subtypes and key driver gene expression of the parent tumor, and lack of organoid histological features and interaction between tumor and normal tissue (Lee et al., 2006; Schulte et al., 2012).