Cytokeratin expression patterns by one- and two-dimensional electrophoresis in pars flaccida cholesteatoma and pars tensa cholesteatoma.

Expression patterns of cytokeratins (CKs) in normal skin, in pars flaccida type cholesteatoma (PFTC), and in pars tensa type cholesteatoma (PTTC) were examined by means of one- and two-dimensional electrophoretic techniques. Both CKs 14 and 5 pair (CKs 14/5) and CKs 10/1 were found in all materials. Neither CKs 16/6 nor 19 was found in the skin. CKs 16/6 and 19 were both found in 3 out of 5 PFTCs, only CKs 16/6 in 1 out of 5 and neither CKs 16/6 nor 19 in 1 out of 5. CKs 16/6 and 19 were both found in 1 out of 3 PTTCs, only CKs 16/6 in 1 out of 3 and neither CKs 16/6 nor 19 in 1 out of 3. There was no significant difference in the CKs expression patterns between PFTC and PTTC. The expression of CKs 16/6 and 19 suggested that their matrix epithelia were hyperproliferative. However, not all of the cholesteatomas were always hyperproliferative. Patterns of the terminal differentiation of CKs 1, 5, 10 and 14 in the PFTC or the PTTC were basically the same as those in the skin. In the cholesteatoma, eack CK gradually diminished in molecular weight in the cornified layer and debris. Desmosomal proteins were abundant in skin but not in cholesteatomas.