The results have generally indicated that polysaccharides of P. linteus exhibit significant antitumor activity against HepG2 through blocking tumor cells going into the S stage, upregulating the expression of P27kip1 and cyclin A, and downregulating the expression of calreticulin, cyclin D1, cyclin E, and CDK2 in vitro and in vivo, but there is an urgent need to verify whether there is a relationship between this remarkable decrease in CDK2 and induced S-phase arrest [35]. The gene discussed is CDK2; the disease is neoplasm.