In the realm of marine biology it has long been observed that bothstarfish and lobsters have very unique traits which, to the best of current biological knowledge, do not occur elsewhere in nature. For one, starfish have regenerative capabilities: if one were to cut off the limbs of a starfish (as many unknowing fishermen have often done) it does not actually kill the starfish...in fact it creates five more in its place. Biologists know that this is an advanced form of budding, but they do not know how or why.
Parallel to this is the growth of lobsters. In controlled experiments, scientists have not been able to observe lobsters dying of "natural" causes. In addition, their growth rate is not known to subside with age: their apparent cellular reproduction causes them to continue growing until the accident curve picks them off. As far as anyone knows, there could be 300 year old lobsters living in the deepest areas of the oceans.
These two observations have been known for quite some time, yet the examples are rarely used in regard to human aging. Furthermore, I have not personally heard of any research pertaining to the cellular and genetic possibilies when applied to humans. If I am wrong, please correct me, but if not, I believe that this is viable area to look to when considering the possibilities of human longevity.