Keratin 8 expression in head and neck epithelia

Background: The intermediate filament forming protein keratin 8
(K8) is a tumour-associated antigen, which was shown to be
over-expressed in a variety of malignancies. Here, we present a
study of K8 expression in squamous epithelia of the head and neck
area, including normal mucosa, hyperplastic and dysplastic
leukoplakia, carcinomas of different sub-localisations, and lymph
node metastases. Methods: K8 expression was assessed upon
immunohistochemistry with specific antibodies in cryosections of
primary tumours of the head and neck area. Results: K8 expression
was characteristic of transformed tissue and marked early stages of
disease, i.e. dysplastic oral leukoplakia, but not normal or
hyperplastic epithelium. With the exception of carcinomas of the
larynx and the tongue, K8 expression also strictly differentiated
carcinomas from normal epithelium of the same origin. Furthermore,
K8(high) was characteristic of cells, which had detached from the
sites of primary tumours and had been invading the surrounding
tissue at the time point of surgery. Conclusion: K8 is an excellent
marker for head and neck malignancies, which allows for early
detection as well as for visualisation of potentially disseminating
tumour cells in vivo.