Basement membrane of cervical adenocarcinoma: an immunoperoxidase study of laminin and type IV collagen. The basement membrane components type IV collagen and laminin were examined immunohistochemically in 14 cases of adenocarcinoma of the cervix. The patterns of staining in adenocarcinoma in situ, invasive adenocarcinoma, and early invasive adenocarcinoma were compared to see whether characteristic patterns could be delineated. Adenocarcinoma in situ had a uniform intact basement membrane, whereas the basement membrane of invasive adenocarcinoma was fragmented and irregular. Cases of early stromal invasion showed early gland buds and outpouchings with defective basement membrane staining. The degree of histologic differentiation of the tumor was not clearly related to the amount of basement membrane component staining. The concept of early stromal invasion in cervical adenocarcinoma, as supported by our immunohistochemical studies, is discussed as it relates to a possible pathogenic mechanism in early invasion and infiltration of adenocarcinoma of the cervix. 