In summary, we provided evidence showing that natural sulfated polysaccharide from brown alga Fucus evanescens effectively suppresses EGF-induced transformation of mouse epidermal cells JB6 Cl41 and colony formation of colon cancer cells through TOPK/ERK1/2/MSK 1 signal pathway by inhibiting TOPK kinase activity in vitro and ex vivo. The gene discussed is MAPK3; the disease is colonic neoplasm.