Biological activity of E. coli expressed FGF2 was measured by cell proliferation assay using MCF-7 cells. Cell proliferation in response to growth factor (FGF2) using MCF7 Cell line was compared with control cells without FGF2 and measured by WST-assay Kit (ab65475) as per the protocol cited. Final reading was calculated after deducting the absorbance at 620 nm from 450 nm and plotted in bar graph. The graph indicated that there is better proliferation in presence of FGF2 in comparison to control.