Hypoxic regulation and prognostic value of LAMP3 expression in breast cancer

Abstract

BACKGROUND: LAMP3 is a newly described hypoxia regulated gene of potential interest in hypoxia-induced therapy resistance and metastasis. The prognostic value of LAMP3 in breast cancer was investigated. METHODS: Expression levels of LAMP3 in breast cancer cell lines and patient tissues were determined by real-time polymerase chain reaction and in a tissue microarray by immunohistochemistry. Immunofluorescent staining was used to evaluate the distribution of LAMP3 in tumor xenografts relative to pimonidazole. Kaplan-Meier analysis as well as multivariate Cox regression survival analyses were performed. RESULTS: LAMP3 was variably expressed in breast cancer cell lines and induced in an oxygen concentration-dependent manner. LAMP3 protein expression colocalized with hypoxic areas in breast cancer xenografts. LAMP3 mRNA was higher in breast tumors from patients with node-positive (P =.019) and/or steroid hormone receptor-negative tumors (P