ObjectiveTo understand research progress of influence of claudins on proliferation and activation for breast cancer. MethodThe relevant literatures of influence of claudins on proliferation and activation for breast cancer were retrieved and reviewed. ResultsThe claudins had 24 members in mammals,claudin-13 was missing in human beings.Expression and distribution mode of the claudins possessed highly tissue-specific,and multiple proteins were expressed in many organizations.The expressions of claudins could be regulated from the levels of transcription and post-transcription,coordinately regulated by the transcription factor and post-synthetic modifications.Claudins were related to epithelial-mesenchymal transition.Now the studies were relatively clear those focused on claudin-1,-2,-4,-6,and other subtypes,and the expression of claudin-1 indicated the poor prognosis of tumor;claudin-2 was closely related to liver metastasis of breast cancer;claudin-4 was closely related to triple negative breast cancer;the function of claudin-6 in the breast cancer was controversial.In addition to the claudins mentioned above,other claudin members also played certain roles in normal breast and malignant breast tumors.Claudin-5 might participate in metastasis of breast cancer through N-WASP and ROCK signal pathway;CD-24 and claudin-7 immunodepression had a certain guiding significance on prognosis of invasive ductal carcinoma;the expressions of claudin-16 and HAPLN3 gene were remarkably increased in human breast cancer;Claudin-20 induced breast cancer cells into a subtype that possessed the high invasiveness and weakened the resis-tance of epithelial-mesenchymal transition.Recently,the claudin-low subtype was proposed,and it differed from other types of breast cancer in many aspects,and also it had a better prognosis than other types of triple negative breast cancer. ConclusionsClaudin,being an important member of tight junction protein,is confirmed to be related to epithelial-mesenchymal transition.Claudins play important roles in dissociaton,activation,invasiveness,and metastasis of breast cancer,but there is no final conclusion which member contributes to invasiveness and metastasis of breast cancer.Moreover,there are opposite conclusions on some certain claudins members in breast cancer which might due to the different subtypes of breast cancer,so,further studies about the function of claudins in different subtypes are needed eagerly.