Antineoplastons work as molecular switches, which regulate expression of genes p53 and p21 through demethylation of promoter sequences and acetylation of histones. They also inhibit the uptake of growth-critical amino acids, such as 1-glutamine and 1-leucine in neoplastic cells. Phase II trials indicate efficacy of antineoplastons in low-grade glioma, brain stem glioma, high-grade glioma, adenocarcinoma of the colon, and hepatocellular carcinoma. The best results were observed in children with low-grade glioma, where 74% of patients obtained objective response, and in patients with adenocarcinoma of the colon with liver metastases whose survival rate of more than 5 years is 91% versus 39% in controls on chemotherapy. Gene array studies will explain antineoplaston-induced changes in gene expression.