EM-1421A substance being studied in the treatment of cancer. It blocks proteins needed for cancer growth. It is a type of transcriptional inhibitor. Also called tetra-O-methyl NDGA and tetra-O-methyl nordihydroguaiaretic acid.Search NCI's Dictionary of Cancer TermsStarts withContainsBrowse:ABCDEFGHIJKLMNOPQRSTUVWXYZ#