is developing tissue that shows a high rate of cell division.
Although there is no consensus on the pathogenesis of these tumors, most investigators believe they originate from early ovarian mesenchyma
as they are composed of granulosa cells, theca cells, and fibroblasts in different degrees .
Traditional theories include metaplastic transformation of the pelvic peritoneum (coelomic metaplasia) ; transplantation of endometrial tissue either through retrograde menstruation, iatrogenic relocation during surgical procedures, or by hematogenous or lymphatic spread ; and induction of undifferentiated mesenchyma
tissue, through unknown mediators in the shed endometrium, to form endometriotic lesions in extrauterine regions .
The cells are activated and undergo epithelial-mesenchymal transition (EMT), a process in which RPE loses epithelial characteristics, such as cell-to-cell contact, but acquire stronger abilities of migration, proliferation, antiapoptosis, and ECMdegradation, which are properties of mesenchyma
Proliferative and mesenchymal subtypes express genes which correlate with cells proliferation and angiogenesis or mesenchyma