The role of PolySia-NCAM in invasion has been established by Suzuki et al., who demonstrated that C6 glioma cells became highly invasive in a mouse model after increasing polysialylation via the transfection of ST8SIA2 or ST8SIA4, while mock-transfected C6 glioma cells exhibited minimal invasion when inoculated into the brain [26]. The gene discussed is NCAM1; the disease is glioma.