2009 Nobel prize given for this work.
Lab animals, due to the way they are bred, are essentially susceptible to cancer and health issues not seen in normal wildtype populations. Shortened telomeres are the primary danger, increasing mutation rate and cell senescence.
Essentially, all data involving the expectation of normal cellular behavior is subject to question - signaling from lab animals is corrupted.
Apparently leukocyte telomere length is heritable though, is that what you are talking about?
Most cancer studies in mice are xenografts of human cancer cells so any relevance of mice telomeres is completely lost anyway.
Also this obsession with telomeres being the fundamental key for all our biological problems seems so conspiratorial. Like you think our cells which do unimaginable things can't keep their DNA ends frothy? Like that's what is gonna spell their doom? Or you consider telomeres are just a symptom of a cells longevity decided by other factors ?
lab rats and mice aren't useful model organisms, but it's not for this reason.
I think this is one symptom of a much greater issue: the inbred mice strains we use are disastrously weird (arising from the initial population artificially bred to make research easier). For the sake of controlling for genetics, we've chosen to make lab research translation drastically less effective.