Nephronectin is Correlated with Poor Prognosis in Breast Cancer and Promotes Metastasis via its Integrin-Binding Motifs

Most cancer patients with solid tumors who succumb to their illness die of metastatic disease. While early detection and improved treatment have led to reduced mortality, even for those with metastatic cancer, some patients still respond poorly to treatment. Understanding the mechanisms of metastasis is important to improve prognostication, to stratify patients for treatment, and to identify new targets for therapy. We have shown previously that expression of nephronectin (NPNT) is correlated with metastatic propensity in breast cancer cell lines. In the present study, we provide a comprehensive analysis of the expression pattern and distribution of NPNT in breast cancer tissue from 842 patients by immunohistochemical staining of tissue microarrays from a historic cohort. Several patterns of NPNT staining were observed. An association between granular cytoplasmic staining (in