Basal membrane associated substances in human salivary glands and salivary gland tumours

Human salivary gland tissue was analysed with respect to the distribution of basal membrane associated substances. Collagen type IV and laminin were studied on the basis of monoclonal antibodies, fibronectin was analysed with polyclonal antibodies. The structure of the basal membrane was well preserved in normal salivary gland tissue. There was a continuous staining of the basal membrane around the acini and the ducts. The labelling for these substances appeared to be associated with the myoepithelial cells. Pleomorphic adenomas exhibited a heterogeneous pattern for the basal membrane substances. Focally, there was an augmentation of collagen IV and laminin, as well as of fibronectin. This was observed in the neighbourhood of myoepithelial like cells. Other parts of pleomorphic adenomas showed an interruption of the basal membrane. Adenoid cystic carcinomas displayed a clear staining of the basal membrane associated substances in the pseudocysts. Stromal trabeculae were stained in an irregular manner. Acinic cell tumours, adenocarcinomas, mucoepidermoid tumours and squamous cell carcinomas (for comparison taken from other regions in the head and neck area) presented a clear destruction of the basal membrane as visualized by antibodies against collagen IV and laminin. The study of the basal membrane substances may be helpful for identifying special features of salivary gland tumours and for grading the amount of invasive behaviour in the malignant tumours.