Prognostic significance of combined serum immunological HER2 and ERα36 biomarkers in estrogen receptor-positive breast cancer subtypes.

BACKGROUND: Breast cancer is the most common cancer among women, with rising incidence and mortality rates, posing clinical treatment challenges. OBJECTIVE: To analyze the prognostic significance of serum immune HER2 and ERα36 biomarkers in estrogen receptor-positive breast cancer subtypes. METHODS: Sixty-one estrogen receptor-positive breast cancer cases from Fourth Hospital of Hebei Medical University (2016-2023) were analyzed. The qPCR was used to detect the expression level of ERα36 mRNA in the sample, and ELISA was used to detect the expression of HER2 in the sample. Associations between biomarker expression, clinicopathological features, and prognosis were evaluated. RESULTS: ERα36 mRNA expression was higher in breast cancer tissues than in adjacent tissues (p < 0.05). High ERα36 expression was associated with menopause (77.78%) and lymph node metastasis (75.00%) (p < 0.05). HER2 positivity correlated with menopause (55.56%) and lymph node metastasis (56.00%) (p < 0.05). No significant differences were found in age, reproductive history, family history, clinical stage, histologic grade, or T stage (p > 0.05). OS rates showed no significant difference, but PFS rates varied significantly (p < 0.05). Patients with high ERα36 expression in HER2-positive cases had the poorest prognosis (p < 0.05). CONCLUSION: ERα36 and HER2 are valuable prognostic biomarkers, with their co-expression linked to increased lymph node metastasis and poorer survival outcomes.