CYTOKERATIN EXPRESSION IN NONNEOPLASTIC ESOPHAGEAL EPITHELIUM AND SQUAMOUS-CELL CARCINOMA OF THE ESOPHAGUS

The expression of cytokeratins (CK) 19, 8, 18, 13, 10 and 7 was examin ed in 35 cases of squamous cell carcinomas of the oesophagus (10 well- differentiated, 13 moderately-differentiated, and 12 poorly-differenti ated) and the adjacent mucosa by means of a panel of monoclonal antibo dies on frozen sections. The study was undertaken to assess the patter n of expression of these keratins in oesophageal tumours and its relat ion to the degree of differentiation. The normal oesophageal epithelia ex pressed CK19 in 86%, CK18 in 17% and CK13 in 14% of cases. CK8, CK 10 and CK7 immunoreactivity was not observed. The tumours expressed CK 19 in 86%, CK8 in 46%, CK18 in 97%, CK13 in 83%, CK10 in 34% and CK7 i n 29% of cases. Thus, the so-called simple epithelial markers CK18 and CK19 occurred in the majority of oesophageal squamous cell carcinomas . CK13 (the so-called non-keratinizing squamous epithelial marker) was only infrequently demonstrated in the non-neoplastic oesophageal muco sa, and its expression was more frequent in carcinomas. CK10 was not d emonstrated in non-neoplastic mucosa, but was mostly associated with w ell-differentiated carcinomas. We therefore conclude that the pattern of expression of cytokeratins in oesophageal carcinomas is different f rom that in normal oesophageal epithelia and varies with differentiati on.