Cancers are brilliant adversaries and because of the fundamental heterogeneity, the variability within a cancer population, there is almost always going to be a population of cells that is primed to survive the attack that we attempt with chemotherapy agents or targeted therapies or immunotherapy. But as has been amply demonstrated by the work that Dr. Groopman referenced in his New Yorker article and also very exciting results with immune therapies for cancer, it's quite clear that we can gain the upper hand and sometimes do so in a durable fashion.