In our case our daughter was 12 when dx, so I don't worry too much over what I did while pregnant. I do know that I was much more health conscious during my pregnancy with her than I was with my son, who is 31 and doing just fine 
I have seen many children that are dx after being very healthy, which was true in my daughter's case as well. Except a nasty round of ear infections between her 1st and 2nd birthdays she was incredibly healthy. No other children in our neighborhood (and few adults) in our neighborhood have been dx w/cancer. We never used poisons or toxic cleaners, I breast fed and we eat organic, for the most part.
At the risk of sounding like a complete fruitcake, (and some of the 'oldies' here know this story) her problems seemed to stem from a serious dog bite she got when she was 9. She was bitten in the lower back by a pit bull and the dog's tooth went into the back of her hip bone right to (and into) the marrow. Within 6 months she was dx'd with idiopathic hypereosinophilia, a very rare condition where the body's eosinophils go nuts and start attacking the body. Her white cells were 40% eos, symptoms were high fevers, severe joint and bone pain that moved around-sound familiar? The docs did a bma to rule out leukemia before they started treating her with high dose steroids, gleevec and interferon alpha. These drugs were never entirely successful in controlling her condition. About a (very long!) year and a half later she was dx'd with pre-b ALL. Interestingly enough, the chemo took care of both the ALL and the hypereos. so we were doubly blessed/lucky.
I realize that this is an extreme and very weird case, and I have no idea if it helps anyone, but I thought I'd put it out here anyway. If nothing else, it shows that every child's case is unique!
Patty mom to Sarah, dx 1/04 hr ALL, OT 8/06 and doing great!
Hello!
Thanks mom. I thought we were busy with 5
Here's my technical take on this emotional topic.
So I think the topic of Epigenetics has a bearing on childhood cancer.
And the fact that you can pass on an environment conducive to mutations without being the origin of the mutation. Theoretically the parents or the grandparents could be the origin of the "presentation" of the genes without actually passing on mutated genes.
Epigenetics deals with the presentation of genes - which structure is "heritable" from generation to generation even IF there are no mutations. That means toxicity from an earlier exposure can "degrade" the epigenetic status - resulting in a "signaling environment" that is conducive to the survival of mutations. Mutations that can themselves direct further epigenetic "modifications" to support their own survival (a downward spiral of malignancy).
So the maligancy of cancer is directly related to supporting genetic AND epigenetic problems.
For example - mutations could normally be trying to shut down the cells (apoptosis) but because of epigenetic issues, the cells refuse to listen.
Also - mutations could be driving growth - but because of epigenetic issues, the cells refuse to differentiate.
The key word relating to this topic, I think, is "heritable". Heritable from earlier to later life. And also theoretically heritable from parents to children. In other words even if teenage smokers avoided cancer, they could still pass on poor epigenetic structure to their children ...that would increase the risk of mutations surviving and becoming malignant.
Could that mean cancer risk would grow over multiple generations of poor diet / toxic environment? I think so.
The good news is, that with epigenetic therapy (things like Green Tea, Curcumin, etc.) the cellular signaling environment that supported the genetic mutations can be adjusted, supporting normal apoptosis and/or differentation, and also sensitising the cells to chemo, radiation, and/or immunology.
See studies:
http://www.ncbi.nlm.nih.gov/pubmed/16563357
http://www.ncbi.nlm.nih.gov/pubmed/17570133
http://www.ncbi.nlm.nih.gov/pubmed/18199978
Sorry to jump in with a lecture ...couldn't help myself
(the "man" thing you know)
In the end - you deal with the genetic (or epigenetic) structure you are born with. But there are common sense dietary things you can do to guard against cancer. And that's not some wacko-health-salesman saying that. See study above. That's M.D. Anderson.
...Dave
I drive myself batty with this even though every doctor you come in contact with assures you it is not your fault and a cause is unkown. My daughter was sick at the time of diagnosis with an upper respiratory and ear infection. She never seemed to get over either infection and then became very pale and didn't play a lot. I took her back to the doctor to see if the infections weren't responding to medicine and the next thing I remember is a phone call telling us to go straight to the hospital. Her labs were very wrong.
I read somewhere (and I can't remember where now - information overload) that developed countries seem to have a higher rate of leukemia. This line of thinking seemed to believe that with less of an exposure to germs, the less your immune systems kicks in, which makes it weaker actually. I wondered about this because my daughter has been on prophylactic antibiotics for most of her 3 1/2 years due to high grade bladder reflux on both sides of her bladder. Of course that makes me wonder about the regular VCUG's she has had to watch the reflux and what the radiation could have down. She had her first x-ray at 3 months. Ah, the things your mind comes up with at three in the morning, huh? 