The GATA3 X308_Splice breast cancer mutation is a hormone context-dependent oncogenic driver

AbstractAs the catalogue of oncogenic driver mutations is expanding, it is becoming clear that alterations in a given gene should not be lumped into one single class, since they might have different functions. The transcription factorGATA3is a paradigm of this. Here, we address the functions of the most commonGATA3mutation (X308_Splice) which generates a neoprotein that we designate as neoGATA3, associated with good patient prognosis. Based on extensive analyses of molecular and clinical data from approximately 3000 breast cancer patients, supported by mechanistic studiesin vitro, we show that neoGATA3 interferes with the transcriptional programs controlled by estrogen and progesterone rece…