Abstract: Objective To analyze the changes in the ratio of helper T cell 17 to regulatory T cells (Th17/Treg), serum ferritin (SF), microRNA-145 (miR-145), and microRNA-132 (miR-132) levels in breast cancer patients and their relationships with pathological parameters. Methods A total of 92 breast cancer patients from January 2022 to December 2023 were enrolled as study group, and 105 patients with benign breast diseases during the same period were selected as control group. Changes in SF, miR-132, Th17/Treg, and miR-145 were compared between the two groups, and the diagnostic value of these indicators for breast cancer was analyzed. Results Compared with the control group, the study group had higher peripheral blood Th17/Treg and serum SF levels, and lower serum miR-145 and miR-132 expression levels (P<0.05). Patients with tumor diameters >2 cm, clinical stages of Ⅲ to Ⅳ, moderately or poorly differentiated tumors, and lymph node metastasis had lower serum miR-145 and miR-132 expression levels than those with tumor diameters ≤2 cm, clinical stages of Ⅰ to Ⅱ, highly differentiated tumor, and no lymph node metastasis (P<0.05). Compared with patients with clinical stages of Ⅰ to Ⅱ, highly differentiated tumors, and no lymph node metastasis, those with clinical stages of Ⅲ to Ⅳ, moderately or poorly differentiated tumors, and lymph node metastasis had higher serum SF levels (P<0.05). Patients with lymph node metastasis had higher Th17/Treg levels than those without (P<0.05). The area under the curve (AUC) for combined detection of Th17/Treg, SF, miR-145, and miR-132 levels in breast cancer patients was higher than that for individual detection (P<0.05), with higher sensitivity and specificity. Conclusion Th17/Treg, SF, miR-145, and miR-132 are abnormally expressed in the blood of breast cancer patients and are correlated with their pathological parameters. Combined detection of these four indicators has higher value in the clinical diagnosis of breast cancer.