NR4A1 and neoplasm: The prevailing model for UF pathogenesis invokes a genetic transformation of a single myometrial stem cell (MM SC) into a tumor initiating stem cell (UF SC) that initiates and maintains monoclonal tumor growth characterized by cell proliferation and extracellular matrix (ECM) production under the influence of endocrine, autocrine and paracrine growth factor and hormone receptor signaling [3, 7].