hallmarks of cancer

cancer cell on molecular level

Cancer arises through the accumulation of genetic and epigenetic alterations that reprogram normal cells into malignant ones. At the molecular level, these changes are captured by the “hallmarks of cancer,” a framework describing the fundamental biological capabilities acquired during tumorigenesis. Key hallmarks include sustained proliferative signaling through oncogene activation, evasion of growth suppressors via inactivation of tumor suppressor genes, and resistance to apoptosis through deregulation of pro- and anti-apoptotic pathways. Genomic instability fuels these processes by generating mutations, while reprogramming of cellular metabolism supports uncontrolled growth. The tumor microenvironment further shapes malignancy by promoting angiogenesis, enabling invasion and metastasis, and fostering immune evasion through altered antigen presentation and checkpoint signaling. Underlying these hallmarks are molecular mechanisms such as aberrant receptor tyrosine kinase signaling, p53 pathway disruption, PI3K/AKT and RAS/MAPK activation, telomerase reactivation, and modulation of immune checkpoints like PD-1/PD-L1. Together, these molecular alterations form a complex network that drives cancer progression and provides targets for precision therapies.