Triple-negative breast cancer (TNBC) is an overly aggressive breast cancer subtype that disproportionately affects African American women. In our preliminary studies, we found that p53 mutations in TNBC often coincided with deletion/silencing of the CDKN2A locus that encodes both the ARF and INK4A tumor suppressors. The purpose of this study is to investigate the potential of targeting JAK1 (through loss of p53 and ARF) and CDK4 (through INK4A loss) activity in treating TNBC and the biomarkers predictive of response. In this project period, we have been focusing on the construction of our Tissue Microarray (TMA). We have reviewed 377 of our 525 desired cases, and have succeeded in placing 180 case specimens in the TMA. We anticipate the completion of the TMA sample collection in the next six months.