The Relationship Among The Expression Of E6, E7 Protein And MCM7 In The Various Cervical Lesion

ABSTRACTCervical cancer, one of the most common female malignant tumors in all the world, is seriously harmful to the women’s physical and mental health. Cervical cancer gradually develops from the cervical intraepithelial neoplasia, which is involved with a variety of factors and phases. The pathogenesis of cervical cancer is still unclear enough. Studying the molecular mechanism at the protein level contributes to elucidating the pathogenesis of cervical squamous cell carcinoma, and then exploring the molecular biomarker as the early diagnosis evidence of the cervical cancer and precancerous lesion.Persistent infection with high-risk human papillomavirus(HPV) has been recognized as the etiological agent for the cervical cancer. The most common HR-HPV type which causes cervical squamous cell carcinoma is the HPV16. HPV DNA gene includes early gene region, late gene region and the long control region. And early gene region contains 6 open reading frames, which encode the E1, E2, E4, E5, E6, E7 early proteins and so on. When HPV 16 DNA gets integrated into the host cellular genome, the E2 gene will be disrupted, lost or inactive. This leads to a derepression of the E6 and E7 viral oncogene, which cause the overexpression of the E6 and E7 proteins. The E6 and E7 proteins are required for the maintenance of the malignant phenotype, and the cell transformation ability is enhanced. Finally, it will cause the cancer.Minichromosome maintenance protein 7(MCM7), one of the MCM family, plays a very important role in the DNA replication and extension. Additionally, MCM7 has been demonstrated in proliferating cells. Recent studies have found that MCM7 may be a highly specific biomarker for proliferating cell. MCM7 is expressed in the normal, dysplastic tissue and malignant tumors.So far, there are only individual reports that MCM7 protein is seen in the cervical cancer. However, the relationship among HPV16 E6, E7 protein and MCM7, and the possible molecular mechanism in the cervical squamous cell carcinogenesis are still not very clear.Objective:This issue will detect the expression of HPV16 E6, E7 protein and MCM7 by immunohistochemistry in the chronic cervicitis, CIN and the cervical squamous cell carcinoma to study the roles of these proteins for precancerous lesions diagnosis. Investigate the closely correlations among HPV16 E6, E7 protein and MCM7 in CIN and the cervical squamous cell carcinoma in order to analyze the effect of the infection with HPV16 for the expression of MCM7, so as to provide an evidence for further revealing the molecular mechanism of the infection with HPV16 in the cervical squamous cell carcinogenic.Methods:1 105 cases of the cervical lesions which were infected with HPV16 were collected including 20 cases of chronic cervicitis, 30 cases of CINⅠ-Ⅱ, 30 cases of CINⅢ and 25 cases of the cervical squamous cell carcinoma.2 HPV16 was detected by polymerase chain reaction and film chip blot.3 Immunohistochemical SP method was used to detect the expression of the HPV16 E6, E7 protein and MCM7 in the chronic cervicitis, CIN and the cervical squamous carcinoma tissues.4 Analysis the data with SPSS17.0, and it is statistically significant when P < 0.05.Results:1 The HPV16 E6, E7 proteins were localized mainly in the nucleus and partly in the cytoplasm, whereas MCM7 protein was localized mainly in the nucleus.2 The HPV16 E6, E7 and MCM7 proteins increased gradually from the chronic cervicitis tissues, CIN Ⅰ- Ⅱ, CIN Ⅲ to the cervical squamous carcinoma tissues, respectively.The positive examination rate of the HPV16 E6 in cervical carcinoma was higher than that in the chronic cervicitis and CINⅠ-Ⅱ, and that in CIN Ⅲ was also higher than that in the chronic cervicitis group and CINⅠ-Ⅱ(P < 0.0083). However, there was no significant difference between CIN Ⅲ and the cervical carcinoma, chronic cervicitis and CINⅠ-Ⅱ(P>0.0083).The expression intensity of the HPV16 E6 protein in the cervical carcinoma was higher than that in the other groups, and that in CIN Ⅲ was also higher than that in the chronic cervicitis group and CINⅠ-Ⅱ. However, there was no significant difference between the chronic cervicitis and CINⅠ-Ⅱ.The positive examination rate of the HPV16 E7 in the cervical carcinoma was higher than that in the chronic cervicitis and CINⅠ-Ⅱ, and that in CIN Ⅲ was also higher than that in the chronic cervicitis group(P<0.0083). However, there was no significant difference between CIN Ⅲ and the cervical carcinoma, CINⅠ-Ⅱ and CIN Ⅲ, the chronic cervicitis and CINⅠ-Ⅱ(P>0.0083).The expression intensity of the HPV16 E7 protein in the cervical carcinoma was higher than that in the chronic cervicitis group and CINⅠ-Ⅱ, and that in CIN Ⅲ was also higher than that in the chronic cervicitis group and CINⅠ-Ⅱ. However, there was no significant difference between CIN Ⅲ and the cervical carcinoma, CINⅠ-Ⅱ and CIN Ⅲ.The positive examination rate of the MCM7 in the cervical carcinoma was higher than that in the chronic cervicitis and CINⅠ-Ⅱ, and that in CIN Ⅲ was also higher than that in the chronic cervicitis group and CINⅠ-Ⅱ(P < 0.0083). However, there was no significant difference between CIN Ⅲ and the cervical carcinoma, CINⅠ-Ⅱ and CIN Ⅲ, the chronic cervicitis and CINⅠ-Ⅱ(P>0.0083).The expression intensity of the MCM7 protein in the cervical carcinoma was higher than that in the chronic cervicitis and CINⅠ-Ⅱ, and that in CIN Ⅲ was also higher than that in the chronic cervicitis group and CINⅠ-Ⅱ. However, there was no significant difference between CIN Ⅲ and the cervical carcinoma, the chronic cervicitis and CINⅠ-Ⅱ.3 The protein level of HPV16 E6 was positively correlated with that of E7 in the cervical tissues(r = 0.760, P < 0.001), the E6 was positively correlated with MCM7(r = 0.831, P < 0.001), and the E7 was also positively correlated with MCM7(r = 0.856, P < 0.001).Conclusions:1 After HPV16 infects the cervix, the E6, E7 oncoproteins and MCM7 can cooperate to promote the development of the cervical squamous cell carcinoma.2 The HPV16 E6, E7 protein and MCM7 detected by Immunohistochemical methods could be used as biomarkers to screening and diagnosing the cervical precancerous lesions, to guide the clinical treatment.