The basal lamina in basal cell carcinoma, Bowen's disease, squamous cell carcinoma and keratoacanthoma: an immunoperoxidase study using an antibody to type IV collagen.

The basal lamina in a variety of skin tumours was assessed with an antibody to type IV collagen and the peroxidase-antiperoxidase (PAP) technique. The antibody was raised in rabbits against type IV collagen isolated from human placental tissue. The basal lamina in Bowen's disease was essentially intact while squamous cell and basal cell carcinomas showed focal loss in areas of tumour cell invasion. However, both tumours showed preservation of basal lamina around the majority of projections and nests of tumour within the dermis. Many keratoacanthomas showed extensive loss of the basal lamina. This loss appears associated with advanced keratinization at the base of the lesion and may represent an involutional change possibly secondary to inflammation. It is concluded that epidermal tumour cells following local invasion may cease migration and produce a distinct continuous basal lamina similar to that of the normal dermo-epidermal junction. Loss of basal lamina appears restricted to foci of ongoing tumour invasion.