NF1 and neoplasm: A second screen using the yeast platform also identified another lead candidate, the isoxazoloanthrone Y100, as being synthetic lethal with ira2Δ yeast, hereafter referred to as nf1Δ. In the present study, we describe the mechanisms by which Y100 inhibits cell growth and/or induces cell death in nf1Δ deficient yeast and NF1-deficient tumor cells.