glutamineA new study from Dr. Varelas’ group has revealed important insights into the molecular mechanisms that control breast cancer cell growth. Their report, recently published in EMBO Reports, describes a role for the transcriptional regulators TAZ and YAP in driving oncogenic growth by promoting the expression of enzymes that control glutamine metabolism. Aggressive breast cancer cells are known to rely on an exogenous source of the amino acid glutamine for efficient growth. This study shows that TAZ and YAP contribute to glutamine dependence and reveals that cells with increased TAZ/YAP activity are vulnerable to compounds that inhibit key glutamine-utilizing enzymes, such as transaminases. Assessing TAZ/YAP activity in breast cancers may therefore offer a means for predicting response to targeted therapies with transaminase inhibitors, representing an exciting avenue for cancer therapy.