ALK and cancer: Other advances have shown that tumor heterogeneity may influence the outcomes of targeted cancer therapy.163,164 For example, some scientists have reported that ALK-targeted therapy differs among cancer patients, with many patients treated with ALK-targeted therapy developing therapy resistance, which results in cancer progression.165 Targeted therapies against other cancers, such as non-small cell lung cancer (NSCLS), also face challenges related to tumor heterogeneity, which impact acquired and inherent drug resistance.166