IGF1R and cancer: Instead, the phenomenon is reminiscent of drug‐tolerant persisters (DTPs), which constitute < 1% of drug‐naïve cell populations, become enriched following exposure to high concentrations of anti‐cancer drugs (> 100‐fold above IC50 values) for > 9 days, and have hyperactive IGF‐1R signaling (Sharma et al, 2010).