Expression And Clinical Significance Of CD44 And Galectin-9 In Cervical Cancer

Objectives:Cervical cancer is the fourth largest gynecology malignant tumor.In recent years,with the popularization of cervical cancer screening,the incidence of cervical squamous cell carcinoma has been showing tendency to descend.However,the tendency of cervical adenocarcinoma is on the contrary.Therefore,searching for new targets to immunotherapy of cervical cancer has been brought to the forefront.Moreover,with the development of tumor immunotherapy,researches of tumor immunity and tumor microenvironment have been paid great attention.Galectin-9 can bind CD44 directly and synergize with transforming growth factor-β receptor to enhance immunosuppression.CD44 is a transmembrane glycoprotein receptor,which is indispensable in cell proliferation,differentiation and migration,and is associated with poor prognosis of many types of tumor patients.Galectin-9 is a glycoprotein,which can not only perform anti-tumor functions,but also have immunosuppressive effect.However,the expression of CD44 and galectin-9 in cervical cancer,and the correlation with clinicopathological characteristics and prognosis of cervical cancer patients have not been fully clarified.The main purposes of this study are(1)to analyze the relationship between CD44(encoding CD44)and LGALS9(encoding galectin-9)mRNA and protein expression and clinicopathological features and prognosis of cervical cancer patients.(2)to analyze the correlation between CD44 and LGALS9 and regulatory genes of tumor immunity by bioinformatics.Methods:(1)The expression of CD44 and LGALS9 mRNA in cervical cancer and normal cervical tissue was compared,and the relationship between their expression and FIGO stage and prognosis of cervical cancer patients was analyzed by using TCGA database.Genes related to CD44 and LGALS9 in TCGA database were screened out by cBioPortal online platform.Then the functional cluster analysis and signaling pathway analysis of those related genes were performed by GO and KEGG.The correlation between immunoregulatory genes(such as CTLA4(encoding CTLA-4)、PDCD1(encoding PD-1)、CD276(encoding B7-H3))with CD44 and LGALS9 was analyzed by cBioPortal.(2)Specimens of 160 cervical cancer patients(including 88 squamous cell carcinoma and 72 adenocarcinoma)who underwent surgical treatment in Peking Union Medical College Hospital from 2012 to 2015 were collected.Patients’ clinicopathological characteristics(age,FIGO stage,type of surgery,degree of tumor differentiation,depth of invasion,lymph vascular space invasion-LVSI,parauterine infiltration,metastasis of lymph node and other places,adjuvant therapy)and prognosis were also retrospectively reviewed.The expression of CD44 and galectin-9 protein in cervical cancer was detected by immunohistochemical staining and the relationship between protein expression and clinicopathological features of patients was analyzed.Results:(1)The expression of LGALS9 mRNA in cervical cancer was significantly higher than that in normal cervix.Patients with higher LGALS9 mRNA expression had longer overall survival time.There was no correlation between CD44 mRNA expression and FIGO stage and prognosis of patients.(2)LGALS9-related genes were mainly involved in immune responses and regulation.There was positive correlation between expression of several co-stimulation immune checkpoint-related genes(such as CD27(encoding CD27)、CD40(encoding CD40))and cytotoxic lymphocyte-related genes(such as IFNG(encoding IFN-y)、GZMB(encoing Granzyme B))and LGALS9.(3)In cervical squamous cell carcinoma,CD44 was both expressed in tumor cells(54.5%)and tumor infiltrating lymphocytes-TILs(71.6%).In cervical adenocarcinoma,CD44 was only expressed in TILs(80.6%),not expressed in tumor cells.Galectin-9 was both expressed in cervical squamous cell carcinoma and adenocarcinoma’s tumor cells(positive rate was 23.9%and 16.7%,respectively)and TILs(positive rate was 72.7%and 80.6%,respectively).The overall expression of galectin-9 was positively correlated with high differentiation of tumor,negative LVSI and negative lymph node metastasis.Conclusions:(1)Expression of LGALS9 mRNA in cervical cancer was significantly higher than normal cervix.Patients with high expression of LGALS9 mRNA had better prognosis.The expression of galectin-9 in cervical cancer was associated with better prognosis of patients.Galectin-9 is a potential target for immunotherapy of cervical cancer.(2)The expression of CD44 was correlated with pathological type of cervical cancer,but not with prognosis of patients.