Researchers at the Johns Hopkins Kimmel Cancer Center proposed two drugs, rejected by cancer experts for being too toxic in standard high doses, for possible cancer treatment after observing their effectiveness in low doses tested on cell cultures. Azacitidine (AZA) and decitabine (DAC) are epigenetic drugs that work to correct cancer-causing DNA alterations. The drugs target a small but dangerous subpopulation of cancer stem cells, which evade most cancer drugs and cause recurrence. In the study, low doses of the drugs caused antitumor responses in breast, lung and colon cancers. Common chemotherapy agents poison and destroy dividing cells by damaging the cell and DNA. Low doses of AZA and DAC could reactivate genes that stop cancer growth without causing immediate cell destruction or DNA damage. Low doses of both drugs are currently approved by the US Food and Drug Administration.