Her research focuses on mechanisms of endocrine resistance in breast cancer. In particular, she studies genomic and epigenetic alterations in acquired hormone resistance, employing pre-clinical models as well as human tissue specimens. Her work, as well as other groups has led to the identification of ESR1 mutations that render constitutive activity and endocrine resistance. More recently she has shown that the ESR1 mutations have allele specific neomorphic functions and are drivers of metastases.