Potential of blood exosomal ENAH, SEPT9, EGF, MMP-9 and CXCL8 for the early screening of breast cancer

Exosomal contents have been recognized as candidate biomarkers for cancer screening and prognosis. The current study aimed to evaluate the potential of the expression levels of exosomal enabled homolog (ENAH), septin 9 (SEPT9), epidermal growth factor (EGF), matrix metalloproteinase-9 (MMP-9) and C-X-C motif chemokine ligand 8 (CXCL8) in the blood for the early screening of breast cancer. Therefore, exosomes were extracted and purified from the peripheral blood of 47 patients with breast cancer, 63 disease controls (DCs) and 33 healthy controls (HCs). Subsequently, the exosomal mRNA expression levels of ENAH, SEPT9, EGF, MMP-9 and CXCL8 were detected by reverse transcription-quantitative polymerase chain reaction. The results showed that the exosomal levels of ENAH and EGF were significantly higher in patients with breast cancer compared with DCs and HCs (both P<0.001). In addition, receiver operating characteristic curves revealed that exosomal ENAH was able to discriminate patients with breast cancer from DCs [area under the curve (AUC), 0.841] and HCs (AUC, 0.859). However, exosomal EGF was only able to discriminate patients with breast cancer from HCs (AUC, 0.776). Furthermore, the levels of exosomal SEPT9 were lower in patients with breast cancer compared with DCs and HCs (P=0.021), and exosomal SEPT9 expression levels exhibited good potential in the discrimination of patients with breast cancer from DCs (AUC, 0.717) and HCs (AUC, 0.830). However, no significant difference was detected in exosomal levels of MMP-9 and CXCL8 among the three groups, and these RNAs showed no discriminative ability. In addition, in patients with breast cancer, the exosomal levels of ENAH were associated with molecular subtypes (P=0.010), while those of MMP-9 were associated with a Ki-67 index of ≥30% (P=0.011). In conclusion, the exosomal levels of ENAH, SEPT9 and EGF in blood samples were able to identify patients with breast cancer, thus providing a novel approach for the early screening of breast cancer.