Triosephosphate isomerase (TPI), a glycolytic enzyme, functions in catalyzing the interconversion of glyceraldehyde-3-phosphate and dihydroxyacetone phosphate and is generally upregulated in tumours. However, there are data suggesting loss in lymphomas. To determine its effects in chicken embryonal fibroblasts (CEF) a plasmid was constructed to allow transfection. Upon culture in a suitable medium, cells transfected with the TPI demonstrated upregulation and were significantly more susceptible to apoptosis compared to controls with decreased proliferation. These finding therefore render a novel mechanism by which CEF can be triggered to undergo death by upregulation of TPI.