Probing the Tyrosine Phosphorylation State in Breast Cancer by Src Homology 2 Domain Binding

Abstract

Pubhc reporting burden for Ms collection of information is estimated to average 1 hour per response, Including the lime for reviewing instructions, searching existing data sources gathering and maintaininn the data neededI andcompletingland renewing this collection of information. Send comments regarding this burden estimate or any other asped of this collection of InfoirnaBorf iffsSÄto" educing this burden to Washington Headquarters AUTHOR(S)Bruce J. Mayer PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)University Abstract (Maximum 200 Words) (abstract should contain no proprietary or confidential information)Improved molecular diagnostic methods that can classify tumors and predict their response to therapy have enormous potential to improve the effectiveness breast cancer treatments. The overall goal of this project is to develop a novel molecular diagnostic method, i: termed SH2 profiling, that can classify cell samples based on their global protein tyrosine phosphorylation state. The first aim is to use an existing SH2 profiling method, based on far-Western blotting, to analyze fresh surgical breast cancer samples. The second aim is to o develop a more high-throughput quantitative reversed-phase SH2 profiling format, and test its usefulness in classifying breast cancer samples. The third aim is to develop histochemical SH2 profiling methods that can be used to analyze archived, formalin-fixed tissue sections, and perform pilot retrospective studies to determine whether SH2 binding patterns have potential prognostic value. In the past year we have made great progress in developing the reversed-phase array and histochemical SH2 profiling formats, and results suggest that these quantitative methods will be useful in classifying breast cancer samples. In the coming year, once HSRRB approval for use of human samples is secured, we will begin to apply these new methods to the analysis of actual breast cancer specimens. SUBJECT TERMS Conclusions 9References 10 Appendices 10-93Mayer, B.J. INTRODUCTIONThe focus is this study is to test whether a novel molecular diagnostic approach, SH2 profiling, can serve as a useful prognostic tool to classify breast cancer. SH2 domains are small protein modules that bind specifically to tyrosine phosphorylated peptides. These domains play an important role in normal signal transduction, mediating the formation of multiprotein complexes in response to changes in tyrosine phosphorylation [1,2]. There are ~116 SH2 domains in the human genome, and different SH2 domains recognize different tyrosine phosphorylated proteins. SH2 profiling is a method in which a battery SH2 domain probes is used to provide a snapshot of the global state of tyrosine phosphorylation in a cell sample [3,4]. Different breast cancers are likely to have different patterns of tyrosine phosphorylation, reflecting differences in the signal transduction pathways active in the tumor, and thus SH2 profiling has the potential to provide a biologically relevant means to classify these tumors. In this project we prop...