Ligand-stimulated cells expressing wild-type fibroblast growth factor receptor 3 (FGFR3) proliferate in the absence of interleukin-6 (IL-6).

A chromogenic dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed on IL-6–starved FGFR3-expressing cell lines and controls in the presence or absence of ligand (acidic fibroblast growth factor and heparin). Pooled B9-WT cells exhibit enhanced proliferation in comparison to cytokine-starved controls only in the presence of ligand. Pooled B9-TD cells demonstrate increased proliferation in the absence of IL-6 and further enhancement of proliferation in response to ligand.