ESR1 and Familial prostate cancer: We decided to further investigate the potential role for GR in AR-resistant prostate cell lines, since it had previously been implicated in castrate resistant disease, it had higher levels of expression than ESR1 in the prostate cancer cell lines, showed an inverse correlation in expression with AR in both the cell lines and patient samples in the TCGA data set, and treatment with dexamethasone altered enzalutamide response in 2 of our 3 AR-null cell lines.