Eight cases of adenoid cystic carcinoma were studied clinico-pathologically and immunohistochemically. The eight cases were classified into three histological grades according to Philip's grading system. Localizations of PCNA, p 53, and EGF were examined by using an immunohistochemical staining method. The results were as follows:
1. Neural invasion was found in 2/3 of the Grade III cases and Vascular permeation was found in all of the Grade III cases.
2. The expression or p 53 protein was detected in only one of the Grade III cases.
3. The PCNA-positive rates in Grade III cases were higher than in Grades III and II.
4. The expression of EGF antigen was not detected in eight cases of adenoid cystic ca rcinoma.