**5. Possible directions in the future**

Once we have discovered one or more proteins that are specifically expressed in patients with endometriosis, the next step is to develop them as a diagnostic test for it. The diagnostic method must have good sensitivity, specificity, positive predictive value, and negative predictive value. What we need to overcome is not only the individual differences in the population, but also the differences in specific tissue protein components and the effects of natural menstrual cycles or hormone effects. Protein chip, protein array mass spectrometry technique have been used to perform a comprehensive search of protein expression profiles of endometriosis patients in order to find a group of proteins with high sensitivity and specificity. Applying the changes in the expression of this group of proteins to diagnose and predict disease will undoubtedly bring about a new endometriosis diagnosis field.
