The EL4 mouse tumor model is widely utilized within the field of oncology due to its ease of use and excellent response to chemotherapy, with tumors typically experiencing a reduction in mass of 70% following chemotherapy treatment with cyclophosphamide and etoposide for three days. As not much is known regarding the biochemical changes that result in these drastic reductions in tumor mass, we decided to analyze treated and untreated tumors using shotgun proteomics to identify the changes that occur in relative protein abundance following chemotherapeutic treatment, which will help determine the biological processes resulting in tumor death.