Approximately 90% of human cancer cells exhibit significant levels of telomerase. does this mean that telomerase is an oncogene?

i. yes, telomerase expression makes cells immortal, and all cancer cells are immortal, so telomerase is an oncogene.
ii. no, telomerase is not an oncogene. all immortal cells are not cancer cells. for example, stem cells are immortal but they are not transformed.
iii. no, telomerase is not an oncogene. it prevents the senescence that would occur due to shortened telomeres, but the cell prolferation might still be mitogen-dependent.
iv. yes, telomerase is an oncogene because it forms complexes with p53 and rb, leading to the inactivation of both tumor suppressors