Immunohistochemical study of chondroitin-6-sulphate and tenascin in the larynx: A loss of chondroitin-6-sulphate expression accompanies squamous cellcarcinoma invasion

Chondroitin 6-sulphate is a glycosaminoglycan component of both cell membra ne and basement membrane proteoglycans, In vitro it can inhibit tenascin, a molecule critical for epithelial cell migration during development and in wound healing. The immunohistochemical expression of chondroitin-6-sulphate and tenascin has been examined in 143 laryngeal biopsies from 38 patients, with particular attention to changes occurring with squamous cell carcinom a invasion, All tissues were formalin-fixed and paraffin-embedded, An avidi n-biotin complex immunoperoxidase technique was used, Immunostaining for ch ondroitin-6-sulphate was seen in the basement membrane and/or cell membrane s of basal and suprabasal cells of the laryngeal epithelium. Immunostaining of cell or basement membrane was seen at least focally in 67 of 71 (94 per cent) biopsies with no atypia, in 39 of 45 (87 per cent) biopsies with mil d/moderate atypia, and in 16 of 16 (100 per cent) biopsies with severe dysp lasia or carcinoma in situ (CIS); but in only 2 of 18 biopsies with invasio n, although in neither of these was chondroitin-6-sulphate immunostaining s een at the actual site of invasion. Tenascin immunostaining was seen along the basement membrane in all biopsies, Those with CIS or invasion showed, i n addition, strong tenascin staining of the adjacent stroma, The loss of ch ondroitin-6-sulphate immunostaining concurrent with squamous cell carcinoma invasion in the larynx suggests that loss of a chondroitin-6-sulphate-cont aining proteoglycan, or a change in proteoglycan side-chain composition, is a critical step in laryngeal epithelial tumour invasion. Copyright (C) 199 9 John Wiley & Sons, Ltd.