These are the premature aging syndromes and they all have to do with cell replication:

Stem cells need to replicate faithfully and efficiently. When they don’t, it’s like you are not filling the bathtub quickly enough with water.

Now some of the most common oncogenes are failures in the ones charged with carrying out cell suicide, although there are also ones that involve ignoring cell signals of anti-growth, anti-invasion, and vascular formation.

Here is an example of failed suicide (apoptosis) from a larger reference page.

When the oncogenes are mutated and cell-suicide is impaired, it is like you can’t fish out the foul stuff from your bath. And when that happens in an immortal, telomerase-active stem cell, you can get a cancer stem cell, and a shot at manifesting a disease that might be hard to fight off.

So in a sense, good health is like keeping a bathtub full of clean water.  The supply of water is nearly endless if we can keep the mesenchymal stem cell library frozen in our cartilage from aging when recruited. And if we can drain out the foul water (mutated stem cells), then we are going to be just fine.