Ouroboros weighs in on a recent demonstration of enhanced longevity via telomerase: "Telomerase is tightly repressed in most somatic cells, and for a very good reason: What do you call a cell with an unlimited division potential that's not a stem cell or germ cell? Usually 'cancer.' ... But what if cancer couldn't form for other reasons? In such a case, we could test the hypothesis that increased regenerative capacity [induced via telomerase] confers increased lifespan. ... why is the effect only on median lifespan? ...Mouse cells have really long telomeres, and telomerase expression is widespread in mouse tissues (though not usually at high enough levels to prevent some telomere shortening at every cell division) ... it makes me wonder what's going on. Could telomerase be doing something else - i.e., something other than lengthening telomeres - that is particularly important in determining median lifespan?" I'd wager on protection of mitochondria, a recently discovered secondary (but possibly more important) action of telomerase.