To detect the expression levels of serum biomarkers in patients with mass-stage granulomatous lobular mastitis (GLM), breast cancer and breast fibroadenoma based on high-throughput sequencing results, and to explore their diagnostic values.

A cross-sectional diagnostic trial was conducted. A total of 165 patients (55 cases in each group) with mass-stage GLM, breast cancer and breast fibroadenoma in the First Hospital of Hunan University of Chinese Medicine from December 2021 to October 2022 were enrolled. Surgical pathological diagnosis was used as the gold standard. General data including age, gender, height, weight and body mass index (BMI) were collected; routine blood tests, liver and kidney function tests were performed. RT-PCR was adopted to detect the serum expression levels of miR-451a, miR-5571-3p, CLN6, 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1) and phosphodiesterase type 4 (PDE4). Statistical differences in clinical indicators and the serum levels of the five biomarkers among the three groups were analyzed. The receiver operating characteristic (ROC) curve and area under the curve (AUC), Pearson correlation analysis and sensitivity analysis adjusting for age as a confounding factor were used to evaluate the diagnostic efficacy, correlation and result robustness of the five serum biomarkers.

The BMI in the GLM group, breast cancer group and fibroadenoma group was 23.9±3.6, 22.4±3.9 and 21.3±3.2 respectively, with a statistically significant difference (F=10.136, P<0.001). There were significant differences in white blood cell count (WBC), neutrophil count (N), neutrophil-to-lymphocyte ratio (NLR), C-reactive protein (CRP), platelet count (PLT) and globulin (GLO) among the three groups (H=73.693, 72.788, 33.533, 56.689, 20.531, 35.497, all P<0.001); all above indicators were significantly higher in the GLM group than in the fibroadenoma group and breast cancer group (P<0.05). Comparison of the serum levels of miR-451a, miR-5571-3p, CLN6, HSD11B1, and PDE4 among the three groups revealed significant differences （H=99.760, 80.560, 73.550, 75.966, 74.998, all P<0.001）. Compared with the fibroadenoma group, the expression of miR-451a and miR-5571-3p was significantly increased in the GLM group [0.95 (0.58, 1.19) and 7.36 (4.38, 9.50)], but significantly decreased in the breast cancer group [0.08 (0.05, 0.14) and 0.48 (0.22, 0.72)] (P<0.001, P<0.01). The CLN6 expression was significantly elevated in both the GLM and breast cancer groups, indicating a significant difference between two groups [1. 14 (0. 80, 1. 69) and 1.38 (1. 00, 2. 22), P<0.001]. The breast cancer group showed significantly higher levels of HSD11B1 and PDE4 [1.80 (1.17, 2.66) and 1.40 (1.01, 2.40)] than the GLM group [0.93 (0.55, 1.37) and 0.69 (0.47, 1.13)] (P<0.01). For GLM group, miR-451a (AUC=0.96, 95%CI: 0.91–1.00), miR-5571-3p (AUC=0.90, 95%CI: 0.85-0.96), and the combined detection of miR-451a and miR-5571-3p (AUC=1.00, 95%CI: 1.00-1.00) exhibited high diagnostic value. For breast cancer group, the combined detection of miR-451a and miR-5571-3p (AUC=0.98, 95%CI: 0.96-1.00) showed high diagnostic value; miR-451a (AUC=0.85, 95%CI: 0.79-0.92), miR-5571-3p (AUC=0.83, 95%CI: 0.76–0.90), HSD11B1 (AUC=0.84, 95%CI: 0.77-0.91) and PDE4 (AUC=0.83, 95%CI: 0.76-0.90) demonstrated good diagnostic value; CLN6 (AUC=0.75, 95%CI: 0.67-0.83) had moderate diagnostic value. For fibroadenoma group, CLN6 had high diagnostic value (AUC=0.91, 95%CI: 0.86-0.95); HSD11B1 (AUC=0.88, 95%CI: 0.83-0.93) and PDE4 (AUC=0.88, 95%CI: 0.83-0.94) showed good diagnostic value; the combined detection of miR-451a and miR-5571-3p (AUC=0.76, 95%CI: 0.63-0.88) had moderate diagnostic value. Correlation analysis demonstrated that miR-451a was moderately positively correlated with miR-5571-3p (r=0.637, P<0.05), CLN6 with HSD11B1 (r=0.402, P<0.05), and HSD11B1 with PDE4 (r=0.503, P<0.05). Both miR-451a and miR-5571-3p also showed moderate positive correlations with WBC, N, NLR and CRP (r=0.434–0.659, all P<0.05).

miR-451a and miR-5571-3p, especially their combined detection, show high diagnostic value for mass-stage GLM. The combination of miR-451a and miR-5571-3p for breast cancer and CLN6 for breast fibroadenoma show promising potential in diagnostic value, which may provide evidences for differential diagnosis.