Mutation, Protein Expression Of Pten Gene And Hpv Infection In Development Of Cervical Adenocarcinoma

Background and objectiveCervical carcinoma is one of the most common gynecological malignancies. Its main histology type consists of squamous carcinoma and adenocarcinoma, squamous carcinoma is majority in cervical carcinoma. Recently, there is an increasing tendency in the incidence of cervical adenocarcinoma. Furthermore, several studies also indicated that the frequency of cervical adenocarcinoma increased in younger women. The etiological factor and pathogenesy of cervical adenocarcinoma is still not known. Early diagnosis and differential diagnosis to cervical adenocarcinoma is difficult. Cervical adenocarcinoma is prone to hematogenous metastasis and lymphatic metastasis, its prognosis is worse. Unlike its squamous counterpart (cervical intraepithelial neoplasia, CIN), cervical glandular intraepithelial neoplasia (CGIN) is still not known enough. So cervical adenocarcinoma is been attented generally.PTEN (phosphate and tensin homology deleted on chromose ten) is a tumor suppressor gene that was discovered in 1997. It plays an important role in regulation of cellular proliferation, differentiation and apoptosis and it occured mutation and abnormal expression in many tumors. PTEN has the highest mutation rate in anti-oncogenes of endometrial carcinoma up to the present. Mutation and deletion of expression is invoked quite early in endometrial carcinoma. Cervical adenocarcinoma is similar endometrial carcinoma in etiology and histology morphous. PTEN may be participated the carcinogenesis in cervical adenocarcinoma. There isn't report of mutation of PTEN in cervical adenocarcinoma in China. Studies to mutation of PTEN in cervical glandular intraepithelial neoplasia aren't reported home and overseas. So study is necessary.HR-HPV (high risk-human papilloma virus) infection is necessary to carcinogenesis of cervical carcinoma, but there is few studies HPV infection in cervical adenocarcinoma, finding indicated that HR-HPV infection is correlated with cervical adenocarcinoma.HPV infection alone is insufficient for development of cervical carcinoma, other genetic events, such as suppressor gene inactivation is likely to be required in addition to infection with HPV for the development of cervical carcinoma. In the topic it is detected that expression and mutation of tumour suppressor gene PTEN and HPV infect in cervical adenocarcinoma, cervical glandular Intraepithelial neoplasia and normal cervix glandular epithelium tissue. To discuss the putative role of expression and mutation of tumour suppressor gene PTEN and HPV infect in the cervical adenocarcinoma carcinogenesis and development .The interaction between PTEN and HPV was examined. To find a better early diagnostic molecule marker to cervical adenocarcinoma.Materials and methods42 cases of cervical adenocarcinoma, 20 cases cervical glandular intraepithelial neoplasia and 28 cases normal cervix tissue were collected in the First Affiliated Hospital and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou women and children's hospital. 42 cases of cervical adenocarcinoma were classified according to the WHO standard. 42 cases of cervical adenocarcinoma include 19 cases of mucinous adenocarcinoma, 10 cases of endometrioid adenocarcinoma, 13 cases of other types( 2 cases of serous adenocarcinoma, 4 cases of clear-cell carcinoma,2 cases of not yet typing carcinoma, 5 cases of adenosquamous carcinoma). All cases were identified by two pathologists. Constituent ratio of age is not statistical significance in three groups (P>0.05). Immunohistochemistry was used to examine the protein expression of PTEN gene in 42 cervical adenocarcinoma, 20 cervical glandular intraepithelial neoplasia and 28 normal cervix tissue. Polymerase chain reation-single strand comformation polymorphism (PCR-SSCP) methods were used to detect mutation of exon 5 and exon 8 of PTEN gene. All the samples were examined for the existence of HPV DNA by in situ hybridization broad-spectrum probe. All the datas were analyzed by SPSS11.5 stastistical package. The comparision of two rates uses the fourfold table Chi-square test and Fisher's exact test of probabilities, the comparision of more than two rates uses R×C table Chi-square test, the relation of two variable are analyzed by Spearman's correlation analysis. The level of significant difference wasα=0.05.Results1. PTEN protein was detected in all normal cervical tissues, in contrast, 25.00% of cervical glandular intraepithelial neoplasia, 54.76% of cervical adenocarcinoma was positive of PTEN protein. The positive rates of PTEN protein in cervical adenocarcinoma and cervical glandular intraepithelial neoplasia was significantly lower than that in normal cervix tissue(P<0.05), the positive rates of PTEN protein in cervical glandular intraepithelial neoplasia was lower than that in cervical adenocarcinoma (P<0.05) . PTEN protein expression positive rate in endometrioid adenocarcinoma, mucinous adenocarcinoma and other type was 20.00%, 47.37% and 92.31%, respectively. PTEN positive rate in endometrioid adenocarcinoma and mucinous adenocarcinoma was significantly lower than that in other type (P<0.05).2. Exon 5 and exon 8 of PTEN mutation rate was 0, 45.00%, 19.05% in normal cervical tissues, cervical glandular intraepithelial neoplasia, cervical adenocarcinoma, respectively. PTEN mutation rate in cervical glandular intraepithelial neoplasia and cervical adenocarcinoma was significantly higher than that in normal cervical tissues (P<0.05) , PTEN mutation rate was significantly higher in cervical glandular intraepithelial neoplasia than that in cervical adenocarcinoma (P<0.05) . Exon 5 and exon 8 of PTEN mutation rate in endometrioid adenocarcinoma, mucinous adenocarcinoma and other type was 40.00%, 21.05% and 0, respectively. Exon 5 and exon 8 mutation rate of PTEN in endometrioid adenocarcinoma was significantly higher than that in other type (P<0.05). But the comparison PTEN mutation rate in mucinous adenocarcinoma and that in endometrioid adenocarcinoma was not statistical significance (P>0.05), the comparison PTEN mutation rate in mucinous adenocarcinoma and that in other type was not statistical significance (P>0.05).3. PTEN protein expression was closely correlated to PTEN gene mutation (P<0.05, r_s =-0.619), PTEN protein expression was significantly higher in the without PTEN gene mutation than those with mutation.4. HPV infection rate was 57.14%, 60.00%, 17.86% in cervical adenocarcinoma, cervical glandular intraepithelial neoplasia and normal cervical tissues, respectively. HPV infection rate in cervical adenocarcinoma and cervical glandular intraepithelial neoplasia was significantly higher than that in normal cervical tissues (P<0.05).5. PTEN protein deletion rate was 36.59%, 38.76% in tissue with HPV infection and without HPV infection, respectively, it was not statistical significance (P>0.05). HPV infection was not correlated to PTEN protein expression.6. PTEN exon 5, 8 mutation rate was significantly higher in the without HPV infection than those with HPV infection (the mutation rate is 30.61% and 4.89% respectively) (P<0.05). HPV infection was correlated to PTEN gene mutation (P<0.05, r_s=-0.327).Conclusions1. Development of cervical adenocarcinoma is correlated with mutation and decrease of its expression product of PTEN.2. PTEN mutation and PTEN protein expression decrease is the early event in the development of cervical adenocarcinoma. PTEN protein expression deletion rate and exon 5 and exon 8 mutation rates is significantly associated with histological type. Determination of PTEN protein expression and exon 5 and exon 8 mutation may be helpful for early diagnosis cervical adenocarcinoma. 3. HPV infection is the significance cause in the development of cervical adenocarcinoma.4. There is a HPV-independent pathway in the development of cervical adenocarcinoma. PTEN mutation is likely to play an important role in the development of cervical adenocarcinoma without HPV infection.