| Minichromosome maintenance proteins (MCMs) are members of the pre-replicative complex that is essential for eukaryotic DNA replication. They are only present within the nucleus throughout the cell cycle, but rapidly downregulated in differentiated cells.Minichromosome maintenance protein is an essential factor for the priming and extention of DNA replication and an important mark for potent cell reproductive activity is the positive expression of MCM. Abnormal expression of this family has been detected in different kinds of tumor tissues Furthermore, positive correlation has been determined between the expression level and the cell proliferation degree, while negative correlation between the expression level and the cell differentiation degree. Therefore, MCM has been recognized as an effective indicator for tumor and precancerous change, as well as a reference index for tumor prognostic evaluation. MCM is a more ideal cell proliferation marker, able to reflect the cell reproductive activity in greater accuracy compared to those traditional indexes.Objective:The aim of this study is to determine the pattern and frequency of MCM2 protein and MCM7 protein expression in chronic cervicitis, cervical intraepithelial neoplasias, cervical squamous cell carcinoma , and compare the labelling index of MCM2 and MCM7 with traditional cell proliferation makers such as Ki67, to explore the significance of MCM proteins as a proliferation maker in judgement of malignant degree in cervical squamous cell carcinoma and early diagnosis of cervical epithelium precancerous change。Methods: The expression of MCM2 and MCM7 were analysed in 50 cervical squamous cell carcinoma(14 well-differentiated samples, 29 moderately-differentiateds- amples,7 Poorly-differentiated samples), 87 CIN samples(29 CINⅠ,28 CINⅡ,30 CINⅢ) and 18 chronic cervicitis by immunohistochemistry staining(Envision methods). Results:1. The morphologic characteristic stained of MCM2,MCM7:Nuclear staining of MCM5,MCM7 was identified the postive outcome.Staining was restricted to the nuclei of basal epithelial cells with some cells in 1～2 suprabasal layers in the tissue of chronic cervicitis.The postive cells ascended with the progress of CIN.The postive cells obviously increased in squamous cancer and lost the regular distribution with most dispersion in the complete layers of epithelial and invasion the subjacent cervical stroma2. The expression of MCM2 protein in different cervical tissue:The expression of MCM2 protein gradually increased from chronic cervicitis to invasive cancer. Among the group of chronic cervicitis,the group of CINⅠ,the group of CINⅡ,the group of CINⅢand the group of cervical cancer, there was significant difference with each other(P<0.05).3. The expression of MCM7 protein in different cervical tissue:The expression of MCM7 protein gradually increased from chronic cervicitis to invasive cancer. Among the group of chronic cervicitis,the group of CINⅠ,the group of CINⅡ,the group of CINⅢand the group of cervical cancer, there was significant difference with each other(P<0.05).4. The relation of the expression of MCM2,MCM7 in invasive carcinoma of cervix to the factors related to clinical pathology:The expression of MCM2 in poor and moderately differentiated squamous cancer markedly exceeded that in well differentiated squamous cancer(P<0.05).There was significant difference between well and moderatedly differentiated squamous cancer(P<0.05). The expression of MCM7 in clinical stageⅢand clinical stageⅡsquamous cancer markedly exceeded that in clinical stageⅠsquamous cancer(P<0.05).There was significant difference between in stageⅢand stageⅡsquamous cancer(P<0.05).The expression of MCM2 showed no significant difference in different ages and lymph node metastasis. The expression of MCM7 showed no significant difference than clinical pathology in invasive carcinoma of cervix.5.The expression of Ki67 protein in different cervical tissue :Ki67 expression was mainly detected in the nucleus. Ki67 positive expression rates in 20 chronic cervitis ,87 cervical intraepithelial neoplasia and 50 cervical squamous cell carcinoma samples were 10.0%,20.7%,46.4%,70.7%,86.0% respectively. The expression of Ki67showed no significant difference in chronic cervitis and CINI(P>0.05),but There was also significant difference between the group of CINⅡand CINⅢ, There was also significant difference between the group of CINⅢand the group of cervical cancer(P<0.05) .6.The relation of the expression of Ki67in invasive carcinoma of cervix to the factors related to clinical pathology: The expression of Ki67showed no significant difference than clinical pathology in invasive carcinoma of cervix(P>0.05).Conclusion:1.The expression level of MCM2, MCM7 increased in gradual manner with the cell differentiation degree, from normal to cancer cell, which could help us to distinguish the nature of cervical epithelial tumor early diagnosis of cervical epithelium precancerous change。2.The expression level of MCM2, MCM7 proteins displayed significant difference between different clinical staging and tumor differentiation degree in cervical squamous cell carcinoma , and the level increased with the higher staging, but decreased with higher differentiation degree.3. MCM2, MCM7 are effective markers for cell proliferation. |
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