To investigate the expression and clinical significance of long non-coding RNA BC200 (lncRNA BC200) in serum exosomes of breast cancer patients.

A retrospective analysis was conducted on clinical data from 100 breast cancer patients and 50 patients with breast hyperplasia treated in the First People’s Hospital of Lianyungang from January 2021 to January 2024. Another 30 healthy women undergoing physical examinations during the same period served as control group. Exosomes were extracted from serum samples, and the morphological characteristics and particle concentration of the exosomes were observed. RT-PCR was used to detect the expression of lncRNA BC200 in exosome samples from the three groups. For measurement data, independent sample t test was used for comparison between two groups, ANOVA for comparison between multiple groups, and LSD for pairwise comparison. The χ² test was used for comparison of categorical data between groups. The diagnostic value of lncRNA BC200 in serum exosomes for breast cancer was analyzed using the receiver operating characteristic (ROC) curve.

Exosomes exhibited a typical round or oval morphology, with clear lipid bilayer structures. The relative expression levels of lncRNA BC200 in serum exosomes were 2.76±0.91, 1.15±0.42 and 0.69±0.18 in the breast cancer group, breast hyperplasia group and healthy control group, respectively, indicating a statistically significant difference among three groups (F=5.087, P<0.001). Further pairwise comparisons revealed that the breast cancer group and breast hyperplasia group showed significantly higher expression levels of lncRNA BC200 compared with the control group (both P<0.001), and the breast cancer group showed significantly higher expression levels of lncRNA BC200 compared with the breast hyperplasia group (P<0.001). Breast cancer patients with advanced clinical stage, higher histological grade and lymph node metastasis had significantly higher expression levels of lncRNA BC200 in serum exosomes (stage Ⅲ-Ⅳ vs stage Ⅰ-Ⅱ: t=5.342, P<0.001; grade 2-3 vs grade 1: t=8.804, P<0.001; lymph node metastasis vs no metastasis: t=5.516, P<0.001). The area under the ROC curve for diagnosing breast cancer with serum exosomal lncRNA BC200 was 0.819 (95%CI: 0.803-0.967, P<0.001), with a sensitivity of 91.73% and a specificity of 84.05%.

The lncRNA BC200 is upregulated in serum exosomes of breast cancer patients, and its expression is associated with histological grade, clinical stage and lymph node metastasis of breast cancer. It may serve as an indicator for clinical diagnosis of breast cancer.