[pragone]

Edit: At the top since I think it may qualify my comments: I think there's a causation/correlation incongruity in this, the parent, and the grandparent posts. Telomere lengthening can lead to cancer; getting cancer is not necessarily a "sure-fire way to increase telomere length"

"Cancer" is an unbelievably broad term. Generally speaking, expression of telomerase and maintenance of telomeres is seen in (many) cancers. The background behind this is that as telomeres shorten with each cell replication, they get to a point where they are too short, and the cell stops dividing. Cancer occurs when cells that are not supposed to divide keep dividing.