Aromatase P450 messenger RNA expression in eutopic endometrium is not a specific marker for pelvic endometriosis

Objective: To determine whether expression of aromatase P450 mRNA in eutopic endometrium is predictive of the presence of pelvic endometriosis. Design: A prospective, multicenter, observational study. Setting: Four tertiary centers for reproductive medicine. Patient(s): Sixty subjects of reproductive age undergoing laparoscopy for subfertility exploration, pain assessment, or sterilization. Intervention(s): Endometrial biopsy at time of laparoscopy. Main Outcome Measure(s): The expression of aromatase P450 mRNA in endometrial specimens was determined by single-tube reverse transcription-polymerase chain reaction (RT-PCR). Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA was amplified in parallel to exclude amplification failure. Result(s): The RT-PCR amplification was successful in 56 of the 60 biopsies (93%). Pelvic endometriosis was diagnosed in 34 patients (61%) and was strongly associated with aromatase P450 mRNA expression in eutopic endometrium. As a diagnostic marker for endometriosis, aromatase P450 mRNA expression yielded a sensitivity of 82%, a specificity of 59%, a positive predictive value of 76%, and a negative predictive value of 67%. If additional uterine pathology was taken in account, the sensitivity increased to 84%, the specificity to 72%, the positive predictive value to 87%, but the negative predictive value remained unchanged (67%). Conclusion(s): Although endometrial aromatase P450 gene expression is highly predictive of the presence of pelvic disease, the relative high incidence of false-negative results and lack of specificity is likely to impair clinical application.