**5. Conclusion**

Telomeres are organized into highly specialized structures at chromosome ends. Telomerase and shelterin plays a role in telomere homeostasis. Along with telomere maintenance, telomere-associated proteins also play a significant role in various cell-signaling pathways. The significance and implication of telomerase and shelterin in human diseases have also been firmly established in various models of degenerative diseases. In cancer, telomerase dysfunc‐ tion has been identified as a critical step for immortalization, although the underlying mechanisms are unclear. The recent identification of telomerase promoter mutations has stimulated research, following which numerous studies have reported similar alterations in various cancer models. In several relevant cancer types, telomerase promoter mutations seem to represent a new biomarker for prognosis with potential applications in presurgical diagnosis and in the monitoring of patients. Mechanisms regulating telomerase promoter mutations also hold immense therapeutic value since they occur specifically in cancers.
