Tumor Heterogeneity as a Driver of Cancer Complexity

Tumor heterogeneity encompasses the inherent diversity observed among cancerous tissues, manifesting at multiple biological levels. This variation may appear within a single tumor mass, across different anatomical sites in the same patient, or between individuals diagnosed with the same tumor subtype. Tumors exhibiting heterogeneity demonstrate distinct biological, morphological, phenotypic, and genotypic attributes. As malignant cells progress over time, they often acquire enhanced heterogeneity through genetic mutations, largely driven by genomic instability, and adapt to the pressures of diverse treatment modalities. Genetically, it includes alterations such as single-nucleotide variants and copy number changes; epigenetically, it involves modifications like DNA methylation patterns and fluctuations in gene expression; and at the protein level, it is reflected in differential proteomic profiles. These heterogeneity layers contribute to the dynamic nature of cancer evolution and therapy response. It is commonly linked to diminished therapeutic efficacy, increased resistance to treatment protocols, and generally poorer prognoses for patients. This complexity can hinder the development of uniformly effective interventions and challenge precision medicine strategies. In this paper, we aim to define and contextualize the concept of tumor heterogeneity, classify its diverse manifestations, and examine its influence on cancer therapy, with particular emphasis on the emergence of therapy resistance.

کلیدواژه ها:

Precision Medicine ، Tumor Heterogeneity ، Genetic Instability ، Molecular Variations