This document discusses the promise of drug repurposing for combination therapy in cancer, highlighting the potential of existing non-cancer drugs like metformin and HDAC inhibitors in synergistic effects with chemotherapeutic agents. It details methods for evaluating drug combinations through bioinformatics and gene expression analysis, focusing on promising pairings for breast cancer and acute myelogenous leukemia (AML). The findings suggest multiple effective treatment combinations and emphasize the importance of considering side effects while proposing new therapies.