Abstract: Methods and assays for diagnosis or prognosis of endometriosis include comparing an expression level or activity of miR-155 and JARID2 in a sample to detect a measurable difference. Therapeutic methods for treating endometriosis in a subject comprise identifying a subject as having a decreased expression level and/or activity of JARID2 in a sample obtained from the subject; and administering an agent that inhibits an activity of an miRNA that targets JARID2 or an agent that inhibits EZH2. Methods for screening for a compound useful for treating endometriosis are also provided and include contacting a cell with an effective amount of a test compound, and detecting whether the expression level or activity level of JARID2 or miR-155 in the cell is altered in the presence of the test compound.