HSPG2 and lichen sclerosus et atrophicus: Interaction between ECM1 protein and perlecan, a major proteoglycan of basement membrane, has been recognized in recent years [16, 17] and circulating autoantibodies against ECM1 have been found in the sera of the patients with lichen sclerosus (LS) [18], which is another dermatological disease with some overlapping histopathological features with LP (hyperkeratosis, hyalinization in upper dermis).