Introduction: Osteopontin (OPN), a multifunctional phosphoprotein, has been implicated in a series of important physiologic and pathophysiologic processes. In breast cancer, OPN functionally contributes to the tumorigenicity of spheroid-forming cells. It also plays a critical role in enhancing the proliferation, tumorigenicity, and ability to display vasculogenic mimicry (VM) of spheroid-forming cells in breast cancer. However, the role of OPN in breast cancer is not clear.
Patients and methods: This study investigated OPN expression and VM in breast cancer patients before neoadjuvant chemotherapy (NACT). Their association with clinicopathologic factors was first analyzed by immunohistochemistry. Then, the response of breast cancer patients to NACT was evaluated. The correlation between the clinicopathologic factors, including the molecular subtype, and the response to NACT was analyzed.
Results: Immunohistochemical analysis showed positive staining of OPN in 40% of the breast cancer patients, whereas VM, which was related to tumor stage, was observed in 30% of cases. OPN expression was found to have a significant correlation with VM (P <0.05). The results also indicated that the clinicopathologic factors were not related to the response to NACT, including the molecular subtype. The multivariate analysis of clinicopathologic features correlated with pathological complete response (pCR) indicated that OPN(+)VM(+) was correlated with pCR (P <0.001).
Conclusion: Our findings underlined that the concurrence of OPN-positive expression and VM can predict the pCR to NACT in breast cancer. The efficiency of NACT in certain patients can be easily predicted by detecting the expression of OPN and VM.
Keywords: osteopontin, vasculogenic mimicry formation, breast cancer, neoadjuvant chemotherapy