1.Immunohistochemical Study of p53 Expression in Premalignant and Malignant Cervical Neoplasms
Tan GC ; Sharifah NA ; Salwati S ; Shiran MS ; Hatta AZ ; Ng HO
Medicine and Health 2007;2(2):125-132
One of the most important cervical cancer risk factors is human papillomavirus (HPV)
infection. The p53 gene is one of the most important targets of the HPV E6 gene. E6
protein has the ability to stimulate p53 degradation, inhibits several functions of wild-type
p53 and it competes with its function including suppression of malignant growth. The aim
of this study is to determine the differences in p53 expressions in pre-malignant and
malignant cervical neoplasms. This is a retrospective study on 100 cases of cervical neoplasms. There were 21 cases of CIN 1, 8 cases of CIN 2, 25 cases of CIN 3, 36 cases
of squamous cell carcinoma, 7 cases of adenocarcinoma and 3 cases of adenosquamous
carcinoma. All cases were evaluated by immunohistochemistry using p53 monoclonal
antibody. Thirty six of the 54 pre-malignant cases (66.7%) were positive for p53 protein, in
contrast to the malignant cases in which, 40 of the 46 cases (87.0%) were positive. The
majority of CIN showed absent to focal staining (29/54, 53.7%). In contrast, 84.8% (39/46)
of the invasive carcinoma showed regional to diffuse staining. The expression of p53 is
greater in the malignant cervical neoplasms than the pre-malignant cervical lesions,
suggesting that p53 overexpression is not an early phenomenon in the pathogenesis of
cervical cancer. It is also shown to be slightly higher in percentage in CIN 2 and 3 when
compared with CIN 1. However, a number of cases were p53 negative, suggesting that
other factors may be involved and further HPV studies are indicated.