The Function Of ABCG2 And MCM2 On The Development Of Salivary Glands And Salivary Gland Tumours

Salivary gland tumors are familiar oral and maxillofacial tumours.There are abnormalities based in the stem cell that underlie salivary gland neoplasia. Nowadays,ABCG2 and MCM2 have been confirmed as markers of stem cells. THE BREAST CANCER RESISTANCE PROTEIN,which will be referred to as BCRP in human and Bcrp in rat in this study,belongs to the ATP-binding cassette transporter G(ABCG)family and is also known as ABCG2,ABCP,and MXR.Members of ABCG,also called the white family,are half transporters with only one ATP-binding cassette and six putative transmembrane domains. Although most of the half-sized ABC transporters are located on the intracellular organelle membrane,immunohistochemical(IHC)studies revealed that BCRP, which most likely forms homodimers,is expressed on the cell-surface membrane in both drug-selected and BCRP-transfected cells,in normal human tissues, BCRP is expressed on the apical membrane of trophoblast cells in the placenta; on the epithelium of the small intestine,colon,brain,prostate,and testis;ducts and lobules of the breast;and in the endothelium of veins and capillaries.MCM2 play an important role for cell adhesion,migration,and differentiation during embryonic development by mediating cell-cell and cell-matrix interactions, MCM2 play a distinctive role on differentiation of epithelial cell types.Our research is to study the expression of ABCG2 and MCM2 in human salivary gland development and salivary gland tumours.Establish the stem cell theory of salivary gland tumour by analyzing the relationship between salivary gland development and salivary gland tumours.Collect 24 embryonic salivary gland samples in different stage,10 normal salivary gland samples,68 different salivary gland tumour samples.Observe the development of embryonic salivary gland through HE-stained sections,and investigate the expression of ABCG2 and MCM2 through immunochemistry sections.Compare and analyze the expression of ABCG2 and MCM2 in embryonic salivary gland and salivary gland tumours.The occurrence of salivary gland begins from 6-7 weeks of embryo.It can be seen on the HE-stained sections that the ectodermal mesenchyme gets together,and epithelial buds proliferate and form the epithelial branches and duct systems,finally the terminal cells differentiate into ductal,myoepithelial and acinous.During the development of salivary gland,the expression of ABCG2 and MCM2 is gradually reduced.In normal adult salivary gland samples the positive cell intersperse in the basal layer of intercalated duct,secretory duct and excretory duct.Cells in different salivary gland tumours are similar to epithelial stem cells and transient amplifying cells in specific embryonic stages.Research conclusions are as follow:1.The result of our experiment shows the distributive characteristic of salivary gland stem cells,which exist abroad in bud stage,but decrease and only exist in the basal layer of intercalated duct,secretory duct and excretory duct in normal adult salivary gland.2.Distinctively salivary gland tumour cells are similar with the distinctively stage embryonic salivary gland epithelial stem cell and transient amplifying cell. Salivary gland tumours maybe come from epithelial stem cells and transient amplifying cells of the normal adult salivary gland.