Academy of Medical Sciences of I.R. Iran Archives of Iranian Medicine 1029-2977 25 12 2022 12 01 Altered Expression of hsa_circ_0001445 and hsa_circ_0020397 in Breast Cancer Representing Associations with BMI and Reproductive Factors 817 827 10.34172/aim.2022.127 EN Zahra Firoozi https://orcid.org/0000-0002-8103-2244 Elham Mohammadisoleimani Hassan Dastsooz https://orcid.org/0000-0002-0679-4425 Abdolreza Daraei Seyed Alireza Dastgheib Atefeh Raoofat Hosein Mansoori Yaser Mansoori https://orcid.org/0000-0002-9101-5552 Mohammad Mehdi Naghizadeh https://orcid.org/0000-0001-5562-103X Journal Article 10.34172/aim.2022.127 2021 04 04 2021 11 21 Background: Circular RNAs (circRNAs), one of the recent subclasses of non-coding RNAs (ncRNAs), show pivotal functions in regulation of gene expression and have significant roles in malignancies including breast cancer (BC). This study was aimed to assess the hsa_circ_0001445 and hsa_circ_0020397 expression and role in BC, as well as the potential circRNA/miRNA/mRNA crosstalk in these contexts. Methods: The expression of hsa_circ_0001445 and hsa_circ_0020397 in 50 breast tumors and 50 normal tissues adjacent to the tumors was investigated using quantitative real-time polymerase chain reaction (qRT-PCR). Finally, bioinformatics analyses were used to uncover hsa_circ_0001445, hsa_circ_0020397-miRNA-mRNA potential regulatory networks. Results: The hsa_circ_0001445 expression was considerably downregulated in malignant tissues compared to their normal counterparts (P=0.020), while the hsa_circ_0020397 showed an upregulated pattern (P<0.001). Additionally, it was observed that the higher expression of hsa_circ_0001445 was associated with hair dye avoidance (P=0.034) and normal body mass index (BMI) (P=0.016) while hsa_circ_0020397 over-expression had an important association with a lack of vitamin D consumption (P=0.039). On the other hand, lower expression of hsa_circ_0001445 was significantly associated with age at menarche ˂14 years (P=0.027). Our study also revealed that the two circRNAs have potential ability to regulate key mRNAs and miRNAs in competing endogenous RNA (ceRNA) networks. Conclusion: It is suggested that hsa_circ_0001445 and hsa_circ_0020397 with two opposite roles may be involved in BC development through sponging some miRNAs regulating ceRNA networks. However, their molecular interactions should be validated by further functional studies.