“Several molecules had already shown some anti-kinase activity (albeit with the coarse profiling tools available at the time). There was the isoquinolinesulfonamide from Hidaka’s work. A group from Japan found that a molecule they named erbstatin inhibited EGFR. A group in Israel, led by Yosef Graziani, showed that quercetin, part of a naturally occurring group of chemicals known as flavones, also affected kinase activity inside some tumor cells. The same had been seen with some isoflavones, which also occurred naturally. And there was staurosporine, the antifungal agent that Levitzki had been exploring as an inhibitor of PKC. The fatal flaw of that compound had been its lack of specificity. Could it be adjusted in a way that led it to one kinase, and one kinase only, inside the cell? The next task was to actually make”