Tenascin expression in normal human adult skin and skin appendage tumours

The expression and distribution of tenascin, an extracellular matrix glycoprotein, was investigated immunohistochemically using an anti-human tenascin monoclonal antibody (RCB 1) in formalin-fixed paraffin-embedded tissues obtained from 79 patients with skin appendage tumours, and compared with adjacent normal skin. Tissue specimens were pretreated with actinase and processed by the labelled streptavidin-biotin method. In normal skin, tenascin immunoreactivity was consistently found around the ductal portion of the sweat glands, around the lower part of the hair follicle and hair bulbs, and around or within blood vessels. Immunoreactivity was also observed variably around secretory coils of the sweat glands, and below the epidermis. No immunoreactivity was seen around the sebaceous glands. Tumours originating from sweat glands and hair follicles expressed tenascin around the tumour cells nests, while sebaceous gland tumours were immunonegative. Thus, tenascin expression in skin appendage tumours generally resembled that in corresponding normal tissue.