Which among the following is TRUE regarding tumorigenesis during aging?
Telomerase reactivation
Telomerase inactivation
Increased apoptosis
Suppression of proto-oncogenes
Telomerase is a ribonucleoprotein that is expressed in stem cells and most cancer cells, but not in somatic cells. More than 90% of human cancers express high levels of telomerase that prevent telomere shoening to critical levels and allow indefinite cell proliferation. Ref: Longo D.L. (2012). Chapter 84. Cancer Cell Biology and Angiogenesis. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.