[dlaxague]

The body has a way of dealing with these cancer cells so that in most cases, it never becomes a problem. It is thought that normal cancer cells are dealt with by the immune system. So why is it that in some instances the immune system stops dealing with cancer cells in a normal way and people develop cancer?

This is one of my favorite questions. We don't seem to have very good answers, but the more they learn, the more it appears that what is different between a successful cancer and one that is killed by the immune system is not that someone's immune system doesn't function correctly and "allows" a cancer. It's not a matter of a weak or malfunctioning immune system. It's a matter of a stealthy, clever cancer. Some cancers (the successful ones) are able to trick the immune system into allowing their presence, or ignoring their presence, or in some cases being completely unaware of their presence. Some are even able to harness some functions of the immune system to aid them in their growth.

The often-heard statement about everyone having cancer cells wandering about all the time is not untrue. But those cancer cells that are recognized and eradicated by the immune system on a regular basis are the unstealthy ones. To call them "cancer" and then to compare them to cancer that has been able to establish itself and form a tumor is misleading.

So it's all about the cancer's characteristics and almost nothing about a given immune system. A person with the most robust immune system imaginable is still susceptible to the stealthy cancer. A robust immune system cannot act if it doesn't receive notice to do so.

Now if there were a way to turn off the stealth function of the successful cancer, or to mark the cancer cells so that the immune system DOES recognize them (think vaccines), we'd be onto something. Research continues, no big breakthru yet.

Debbie Laxague