Corning offers a range of growth factors that are derived from different species, both natural and recombinant. These growth factors have been used to promote long-term proliferation in cell culture and to induce cell differentiation in a variety of cell types under serum-free or reduced serum conditions. Corning offers a range of growth factors that are derived from different species, both natural and recombinant. These growth factors have been used to promote long-term proliferation in cell culture and to induce cell differentiation in a variety of cell types under serum-free or reduced serum conditions.