Tumor heterogeneity: biological basis, evolutionary dynamics, emerging technologies, and clinical implications

Tumor heterogeneity is a fundamental hallmark of cancer and one of the major challenges of modern oncology. Genetic and epigenetic alterations, as well as interactions with the tumor microenvironment, drive the continuous emergence of distinct cellular subpopulations, generating dynamic intratumor heterogeneity mediated by clonal evolution. These processes promote tumor progression, metastatic dissemination, therapeutic resistance and disease recurrence. Recent advances in next-generation sequencing, liquid biopsy, single-cell sequencing and spatial transcriptomics have substantially improved our knowledge of tumor evolution and enabled more extensive characterization of tumor diversity. This review summarizes the biological mechanisms underlying tumor heterogeneity, the major evolutionary
models of tumor development and current technologies used to investigate tumor evolution. In addition, we discuss the clinical implications of tumor heterogeneity, such as treatment selection, resistance mechanisms and longitudinal disease monitoring. Finally, we discuss emerging technologies and future perspectives that could facilitate the integration of tumor evolution into precision oncology and support the development of more effective personalized therapeutic strategies.