Analyzing the Blueprint: Exploring the Molecular Profile of Metastasis and Therapeutic Resistance.

Metastases are the leading cause of cancer-related deaths. The spread of neoplasms involves multiple mechanisms, with metastatic tumors exhibiting molecular behaviors distinct from their primary counterparts. The key hallmarks of metastatic lesions include chromosomal instability, copy number alterations (CNAs), and a reduced degree of subclonality. Furthermore, metabolic adaptations such as enhanced glycogen synthesis and storage, as well as increased fatty acid oxidation (FAO), play a critical role in sustaining energy supply in metastases and contributing to chemoresistance. FAO promotes the infiltration of macrophages into the tumor, where they polarize to the M2 phenotype, which is associated with immune suppression and tissue remodeling. Additionally, the tumor microbiome and the action of cytotoxic drugs trigger neutrophil extravasation through inflammatory pathways. Chemoresistant neutrophils in the tumor microenvironment can suppress effector lymphocyte activation and facilitate the formation of neutrophil extracellular traps (NETs), which are linked to drug resistance. This article examines the genomic features of metastatic tumors, along with the metabolic and immunological dynamics within the metastatic tumor microenvironment, and their contribution to drug resistance. It also discusses the molecular mechanisms underlying resistance to chemotherapeutic agents commonly used in the treatment of metastatic cancer.