Novel histone demethylase LSD1 inhibitors were found to specifically inhibit the proliferation of pluripotent cancer cells including teratocarcinoma,embryonic carcinoma,and seminoma or embryonic stem cells that express the stem cell markers Oct4 and Sox2 while displaying minimum growth-inhibitory effects on nonpluripotent cancer or normal somatic cells.Our findings establish LSD1 and histone H3K4 methylation as essential cancer-selective epigenetic targets in cancer cells that have pluripotent stem cell properties.