Significance of p85 expression as a prognostic factor for patients with breast cancer

p85, the regulatory subunit of phosphatidylinositol 3-kinase (PI3K), functions in the pathogenesis and progression of human breast cancers. Previous studies have observed that p85 isoforms may correlate with cancer cell proliferation. In the present study, immunohistochemical staining of p85 was performed in 126 primary breast cancers. The association between the expression levels of p85 with clinicopathological variables, subtypes and prognosis was studied. The breast cancer specimens were divided into three subgroups according to the expression levels of p85 protein. High p85 protein expression was significantly correlated with tumor grade, vascular invasion and recurrence and/or metastasis (P<0.05). Increased p85 protein expression was associated with the human epidermal growth factor receptor 2-positive and triple-negative breast cancers (P=0.008). Patients with higher p85 protein expression levels showed shorter disease-free survival and overall survival times as compared with those with lower expression levels of p85 (P<0.001). Cox proportional-hazards analysis showed that p85 protein expression was not an independent prognostic factor. Further large-scale studies are required to evaluate the significance of p85 protein expression as a prognostic marker for breast cancer.