Expression of low molecular weight cytokeratin proteins in laryngeal dysplasia

In twenty-three cases of laryngeal dysplasia frozen mucosal strips were examined with four monoclonal and one polyclonal keratin antibody. The expression of specific keratin polypeptides was studied in different degrees of dysplasia with regard to the subunits expressed in normal and carcinomatous laryngeal epithelium in the same patient. An alteration in the expression of the subunits of cytokeratin in favour of low molecular weight polypeptides takes place in the transformation of normal epithelium to squamous cell carcinoma. This alteration seems to occur at an early stage and is present already in mild dysplasia. The results suggest that with a suitable antibody dysplastic laryngeal epithelium can be distinguished from normal epithelium, and also on some cases, mild dysplasia from more severe degrees of dysplasia. CAM 5.2, which identifies lower molecular weight cytokeratin proteins (50, 43 and 38 kD), is such an antibody, and can be a valuable diagnostic aid in the histological interpretation of laryngeal dysplasia.