FN1 and endometriosis: To determine the extracellular matrix (ECM) preferred for lesion adhesion, we used our spontaneously immortalized cell line from mouse endometriosis lesions (mEmLe) (42) in an ECM array assay to delineate lesion attachment at the single-cell level based on their ability to attach to the ECM components fibronectin, collagen I, collagen IV, laminin I, and/or fibrinogen.