Abstract:Objective To explore the role and clinical significance of chromatin remodeling gene-AT-rich interactive domain 2(AIRD2) in the occurrence and development of mammary Paget′s disease (MPD). Methods Thirty MPD patients complicated with breast cancer admitted to the Affiliated Hospital of Xuzhou Medical University from March 2011 to January 2019 were selected.Thirty pairs of paraffin-embedded tissue samples from patients with MPD and associated breast cancer were collected.The expression levels of ARID2 and breast cancer molecular markers ［estrogen receptor(ER),progesterone receptor (PR),human epidermal growth factor receptor 2 (HER2),tumor cell proliferating nuclear antigen(Ki-67)］ were detected by immunohistochemistry,and HER2 expression was detected by immunofluorescence in situ hybridization (FISH) in two types of tissues.The difference of ARID2 expression between paired samples,the associations of ARID2 expression with breast cancer molecular markers,molecular typing (based on ER,PR,HER2 results),clinicopathological parameters and survival were analyzed，and the consistency of molecular phenotype among paired samples was analyzed. Results The positive rate of ARID2 was 66.7% in MPD tissues and 30.0% in breast cancer tissues(P<0.01).ARID2 expression was not significantly correlated with expressions of ER,PR,HER2,Ki67,associated breast cancer type,molecular typing,lymph node metastasis,clinical stage and survival (all P>0.05).The consistency rates of expressions of ER,PR,HER2 and molecular typing between MPD epidermal tumor cells and associated breast cancer tissues were 70.0%,73.3%,96.7% and 63.3%,respectively.HER2 had the highest consistency rate between two types of tissues. Conclusions MPD is closely related to associated breast cancer.ARID2 and especially,HER2 may play the role in the occurrence and development of MPD.However,the further study is needed for the significance and mechanism of ARID2 and HER2 expressions.