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.
Immunohistochemical Study of p53 Expression in Premalignant and Malignant Cervical Neoplasms
Abstrak
Salah satu faktor risiko penting dalam kanser serviks adalah jangkitan virus papiloma manusia (human papillomavirus - HPV). Gen p53 merupakan salah satu sasaran utama gen E6 HPV. Protein E6 mempunyai keupayaan untuk merangsang degradasi p53, menghentikan beberapa fungsi p53 jenis-liar dan bersaing dengan fungsi lain p53 seperti mencegah pertumbuhan kanser. Tujuan kajian ini adalah untuk mengenalpasti perbezaan pengekspresan p53 dalam neoplasia serviks pra-malignan dan malignan. Kajian retrospektif ini melibatkan 100 kes neoplasia serviks [21 neoplasia serviks intraepitelial 1 (cervical intraepithelial neoplasia 1- CIN1), 8 CIN2, 25 CIN3, 36 karsinoma sel skuamus, 7 adenokarsinoma dan 3 adenoskuamus karsinoma). Semua kes dikaji dengan kaedah immunohistokimia menggunakan antibodi monoklonal p53. Tiga puluh enam daripada 54 kes pra-malignan (66.7%) adalah positif terhadap protein p53 berbanding dengan 40 daripada 46 kes malignan (87.0%) yang menunjukkan kepositifan. Dua puluh sembilan daripada 54 (53.7%) kes CIN menunjukkan sama ada pengekspresan fokal atau tiada pengekspresan. Sebaliknya, 84.8% (39/46) kes karsinoma invasif menunjukkan pengekspresan regional atau pengekspresan keseluruhan. Pengekspresan p53 didapati lebih tinggi dalam neoplasia serviks malignan berbanding lesi serviks pra-malignan. Ini mencadangkan bahawa pengekspresan p53 bukan satu fenomena awal dalam patogenesis kanser serviks. Kajian ini juga menunjukkan terdapat peningkatan peratusan pengekspresan p53 dalam CIN2 dan CIN3 berbanding dengan CIN1. Akan tetapi, terdapat beberapa kes yang tiada pengekspresan p53 mencadangkan kemungkinan penglibatan faktor-faktor lain dan kajian HPV lanjutan adalah diperlukan.
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