For starters, you are aware that one of the ways cancer cells keep dividing is that they do reactivate telomerase? So reactivating telomerase gives a shortcut for cells to turn into cancers.
Also, it appears that many cancers arise from adult stem cells. They do so because those cells do activate telomerase when they divide.
Reactivating telomerase in all cells may be a way to shorten lifespan by getting multiple cancers.
Part of aging and lifespan has to do with the accumulation of damage to DNA by radiation, reactive oxygen species, etc. This leads, hopefully, to apoptosis and cells death. However, if it does not, then telomere shortening is another way to generally stop cells from continuing to divide after they have accumulated DNA damage during their life.
Curing cancer diseases needs early attention by yourself, community members who have passionate towards health symptoms detection, awareness to control the diseases that cost a lot when it goes to the critical stage of caring.