Urokinase receptor splice variant uPAR-del4/5-associated gene expression in breast cancer: identification of rab31 as an independent prognostic factor

Purpose To evaluate the pure prognostic impact of the uPA-receptor splice variant uPAR-del4/5 for lymph node-negative breast cancer patients, and to identify differentially expressed genes associated with high or low uPAR-del4/5 mRNA levels. Patients and methods mRNA transcript levels were measured by real-time PCR in tumor samples from 280 node-negative breast cancer patients who had not received adjuvant systemic therapy. Endpoints were distant metastasis-free survival (DMFS) and overall survival (OS). Gene expression analysis was performed with RNA isolated from breast cancer tissue and breast cancer cell lines using Affymetrix U133a GeneChips. Results In multivariate analysis, uPAR-del4/5 significantly contributed to the base model of traditional prognostic factors for DMFS (HR = 3.29, P