Serum levels of apolipoprotein E correlates with disease progression and poor prognosis in breast cancer.

ApoE has been reported to be associated with tumorigenesis and tumor progression. In this study, we explored the potential diagnostic and prognostic role of serum ApoE in breast cancer patients. Subject cohorts consisted of 152 normal healthy controls female and 257 breast cancer cases. Serum levels of ApoE were determined with turbidimetric immunoassay. The serum levels of ApoE were significantly elevated in breast cancer patients compared with normal healthy controls (45.82 ± 13.96 mg/L vs. 33.61 ± 6.44 mg/L, respectively, P < 0.0001) and also significantly associated with TNM stage and lymph nodes status (all P < 0.05). Area under receiver operating characteristic curve for serum ApoE discriminate breast cancer patients from controls was 0.786 with specificity of 0.974 and sensitivity of 0.541, the cut-off value of ApoE was 43.15 mg/L. Kaplan-Meier log rank analysis showed that the high serum ApoE group (serum ApoE ≥ 43.15 mg/L) had a poorer progression-free survival and overall survival compared with low serum ApoE group (serum ApoE < 43.15 mg/L) (all P < 0.05). In addition, univariate and multivariate Cox regression analysis displayed serum ApoE as an independent risk factor of breast cancer patients prognosis (all P < 0.05). Serum ApoE played a role as serological biomarkers that indicated diagnostic and prognostic evaluation in breast cancer patients.