ABNORMAL EXPRESSION AND MUTATION OF P53 IN CERVICAL-CANCER - A STUDY AT PROTEIN, RNA AND DNA LEVELS

Objectives: The objectives of this study are to document the status of p53 expression and mutation in cervical cancer at protein, RNA and DN A levels and to relate this to the presence of HPV. Materials and meth ods: Biopsy specimens from one hundred and three squamous cell carcino ma of the cervix and histologically normal ectocervix were analysed. F resh tissues were extracted for protein, RNA and DNA and flash frozen tissue cryostat sectioned for immunohistochemical staining. HPV DNA st atus was determined by PCR using L1 consensus primers and typed for HP V 16 and 18 with E6 specific primers, p53 expression was determined at the protein level by Western blotting an protein extracts and at RNA level by Northern blotting. Results: There was no p53 overexpression o r mutation detectable in the protein extracts. Three of 65 (4.6%) of t he carcinomas were positive for p53 by immunostaining with the polyclo nal antibody CM1. Overexpression at the RNA level was detected in 2 of 32 (6.3%) carcinomas. p53 mutation was screened for by PCR/SSCP (sing le strand conformation polymorphism) followed by sequencing to define the site of mutation. Two of the cervical cancers (2.0%) showed mutati on in p53 in exons 7 or 8. The mutation rate in HPV positive tumours w as 1.2% (1/81) and in HPV negative tumours was 5.2% (1/19). Conclusion : p53 overexpression or mutation does not seem to play a significant r ole in cervical carcinomas.