[1] Northwestern Univ, Dept Pathol, Feinberg Sch Med, Chicago, IL 60611 USA
[2] Northwestern Univ, Dept Obstet & Gynecol, Feinberg Sch Med, Chicago, IL 60611 USA
[3] Shandong Univ, Dept Gynecol & Obstet, Jinan 250100, Peoples R China
[4] NYU, Dept Pathol, Longue Med Sch, New York, NY 10016 USA