Abstract: Introduction/Objective: Breast cancer (BC) is the first leading cause of cancer-related mortality in females worldwide. We have investigated the correlation between circ-ITCH gene polymorphisms, circ-ITCH expression, and their effect on catenin levels and BC development. Methods: Participants included 62 BC and 62 controls matched in terms of age. The circ-ITCH polymorphisms rs10485505 and rs4911154 were genotyped using whole blood samples. In addition, mRNA expression analysis of circ-ITCH was performed on BC tissues. The catenin levels in serum samples were measured using ELISA. Results: The qRT-PCR results demonstrated that circ-ITCH was significantly downregulated in BC compared to normal healthy tissues. The genotype distribution of rs10485505 and rs4911154 were significantly associated with BC risk. For rs10485505, genotype CT and TT were significantly associated with an increased BC risk. In contrast, there was a significant association between rs4911154, genotypes GA and AA, and an increased BC risk. Regarding the rs10485505 genotype, carriers of the T allele frequently have a poor prognosis compared to carriers of the CC genotype. Serum catenin in the BC patients’ group was significantly higher than in the control group. The relative expression levels of circ-ITCH were remarkably decreased in the BC samples of patients carrying the A allele at rs4911154 compared to patients with a GG genotype. Conversely, catenin protein levels were increased in patients carrying the A allele. At the same time, rs10485505 genotype carriers of the CT and TT genotypes showed downregulation of circ-ITCH expression fold compared to the CC genotype. Contrarily, catenin levels markedly increased in TT and CT genotypes compared with the CC genotype. Conclusions: Our research showed that the rs10485505 polymorphism (T allele) and the rs4911154 polymorphism (A allele) are associated with the risk and prognosis of BC. This finding may be due to the effect on the level of circ-ITCH mRNA expression in BC tissues as well as the level of catenin in BC patients.