Charting intratumor heterogeneity from bench to bedside

Intratumor heterogeneity poses a fundamental challenge across the cancer care continuum, from diagnosis to treatment resistance and metastasis. Over recent decades, multiregion and multiomic profiling of tissue, together with functional studies and longitudinal plasma sampling, have revealed the dynamic and multidimensional evolution of tumor ecosystems. This complexity spans genetic and non-genetic mechanisms within cancer cells and their microenvironment. In this Review, we synthesize the current understanding of heterogeneity and evolution and discuss how these insights can inform the development of evolution-aware diagnostic and therapeutic strategies.