P53 EXPRESSION IN CHOROID-PLEXUS NEOPLASMS - AN IMMUNOHISTOCHEMICAL STUDY

Objective.-To evaluate choroid plexus neoplasms for p53 expression. Ca se Material.-We studied 10 choroid plexus tumors (four papillomas and six carcinomas) by immunohistochemistry using the DO7 anti-p53 monoclo nal antibody. Results.-Three of four choroid plexus papillomas demonst rated no staining. Scattered nuclear and rare cytoplasmic positivity w as present in one papilloma, which showed foci of increased mitotic ac tivity (labeling index 2.5%). Six of six carcinomas were immunoreactiv e for p53, and three cases had labeling indexes of over 70%. All immun opositive choroid plexus tumors (7/7) exhibited nuclear staining. Punc tate cytoplasmic positivity was identified in 5 of 7 cases. Conclusion .-Our study suggests that altered p53 expression is detectable by immu nohistochemistry in choroid plexus neoplasms and is consistently prese nt in choroid plexus carcinomas.