Role of phosphoserine phosphatase-like in breast disease in African American women

Abstract #2095 Background: Although breast cancer incidence is higher among Caucasian women (CW), mortality is higher in African American women (AAW). AAW also tend to be diagnosed at a younger age and with larger and more aggressive tumors. Previously, we have found that gene expression patterns in AAW and CW differ in both breast tissues from women without breast disease as well as those from women with invasive breast cancer. Characterization of these differentially expressed genes is critical to understanding breast pathogenesis in AAW. Methods: Total RNA was isolated from breast tissue from 29 AAW and 26 CW without evidence of breast disease using the RNeasy Lipid Tissue Midi kit (Qiagen) and from laser microdissected primary breast tumors from 23 AAW and 24 CW using the RNAqueous Micro kit (Ambion). Based on earlier microarray results, genes were selected for validation by quantitative real-time PCR using TaqMan Gene Expression Assays (Applied Biosystems). All TaqMan assays were performed on duplicate samples using the iCycler Real-Time Detection System (Bio-Rad). Relative expression levels were determined using the Comparative Ct Method. A Wilcoxon test was used to determine significance. Results: Among those genes that were confirmed to be differentially expressed in breast tissues from AAW and CW was phosphoserine phosphatase-like, or PSPHL. PSPHL showed significantly higher expression in both disease-free samples as well as primary tumors from AAW when compared to the same sample type from CW. In tissues from disease-free women, the relative level of PSPHL expression was significantly higher in AAW (median = 17.15) compared to CW (median = 0; P