And there's always the chance that a drug to cure that particular mutation doesn't exist. What then? Spend millions on years of research to make the drug? This

And there's always the chance that a drug to cure that particular mutation doesn't exist. What then? Spend millions on years of research to make the drug? This is indeed the case for most mutations that we're finding in cancer genomes. (That's the bad news). The good news is that many cancers do have "druggable" genes that are altered, and even though the cells have many mutations, attacking just the druggable gene is often enough to prolong life and improve outcomes. The other good news is that even though many different genes can be mutated, there are a much smaller number of pathways that are altered. (those for cell cycle control, apoptosis, etc). By targeting key points in those pathways, one drug may be effective against dozens of different mutations.