642 Background: Chemokine receptor CXCR4 and its ligand CXCL12 (SDF-1alpha) are important in the metastatic spread of breast cancer. Previous studies have shown that CXCR4 is overexpressed in breast cancers as compared to normal breast tissue and that estradiol increases levels of CXCL12. The association between CXCR4 and estrogen receptor (ER) status is unclear. Methods: We performed genome-wide molecular analysis of 61 primary breast cancer tissue samples. Total RNA was extracted and hybridized to Affymetrix HG-U133 oligonucleotide microarrays, and differentially expressed genes between groups were identified using a Welch t-test. CXCR4 protein expression was evaluated by immunohistochemistry (IHC) using a monoclonal antibody (R&D Systems, Minneapolis, MN). We characterized CXCR4 nuclear staining as high vs low-medium. Several clinico-pathologic variables were correlated with CXCR4 expression. Results: A predominantly nuclear staining pattern was noted for CXCR4. Of 61 primary tumors, 15 had high nuclear expression and 46 had low-medium expression. High levels of nuclear CXCR4 expression were significantly correlated with ER-negativity (p =0.0005). CXCR4 protein expression had no association with Her-2 status (gene copy number or IHC 3+), tumor size, or lymph node status. Using p<0.001, protein expression of CXCR4 was associated with 105 significantly differentially expressed genes including relative under expression of ER and ER-related genes and over expression of VEGF. Conclusion: High nuclear protein expression levels of CXCR4 in primary breast cancers are significantly associated with ER-negativity and with low differential expression of ER and ER-related genes. Since estrogen may play a role in CXCR4 activation, further investigation of the association of high CXCR4 expression and ER-negativity is planned. No significant financial relationships to disclose.
P16 Protein Expression in Primary Cutaneous Melanoma with Positive and Negative Lymph Node Biopsies: Particular Aspects of a Study Performed At the Hospital De Clinicas De Porto Alegre, Brazil