As S-adenosyl-L-methionine (SAM)-competitive EZH2 inhibitors are highly selective and are currently showing promise in clinical trials for lymphoma and malignant rhabdoid tumors36, we decided to test whether the preclinical EZH2 inhibitor UNC199937 could restore expression of PTEN in breast cancer cell lines. The gene discussed is EZH2; the disease is breast cancer.