ESR1 and prostate cancer: Because estrogen/ERα signaling induced EMT and is known to promote mesenchymal stem cell differentiation to osteoblasts and bone formation (our unpublished data, [34, 35], we hypothesized that estrogen/ERα signaling may induce prostate cancer cells to become bone-forming osteoblast-like cells, a phenomenon widely reported by others as osteomimicry phenotype [36, 37].