c-Src expression is predictive of poor prognosis in breast cancer patients with bone metastasis, but not in patients with visceral metastasis.
ABSTRACT c-Src expression is critical for breast cancer progression and it is particularly important for bone metastasis. In this study, we aimed to evaluate the effect of c-Src on prognosis in metastatic breast cancer patients, and to conduct subgroup analysis to explore the role of c-Src in bone metastasis and visceral metastasis respectively. We analyzed a total of 102 paraffin-embedded primary tumor tissue sections from metastatic breast cancer patients using immunohistochemical staining for c-Src, including 61 patients with bone metastases. Clinical data were collected retrospectively. We utilized survival analysis and the Cox proportional hazards model to explore the prognostic value of c-Src expression in metastatic breast cancer. The c-Src expression rate was 54.9% in the 102 metastatic breast cancer patients. Patients who exhibited c-Src expression demonstrated poor progression-free survival (PFS) (p = 0.044) and disease-specific survival (DSS) (p = 0.017). Subgroup analysis demonstrated that c-Src positive patients exhibited significantly worse bone metastasis-free survival (p = 0.027) and DSS (p = 0.024), whereas in patients with non-bone metastasis no significant difference was observed in PFS (p = 0.819) and DSS (p = 0.381). Multivariate analysis demonstrated that c-Src expression was an independent predictor of DSS for patients with bone metastasis. Our findings demonstrate that c-Src expression is a potential independent predictor of poor prognosis in breast cancer patients with bone metastasis.