Are there circumstances when providing genetic information alone could do more harm than good?
Let me just touch on one final issue in testing before I move on to talk about therapies. And that is, where there is an environmental stimulus that activates a genetic predisposition to a disease, but it is not yet known, could providing genetic information alone do more harm than good? Now, this is a very important area because one of the more exciting frontiers of research currently has to do with the interface between genetic susceptibility and the environment or the environmental factors that switch on the susceptibility gene or trigger it and cause it to activate. We know far too little about this delicate balance, this delicate interaction between environments and genetic predisposition.
For some conditions, we know. For example, for xeroderma pigmentosum, we know that if somebody with this genetic condition is exposed to ultra violet light, that person will develop a usually untreatable and fatal form of melanoma. For people with this genetic condition, avoidance of ultraviolet light, staying out of the sunshine, living in a twilight world, is one thing that can be done to prevent the onset of the disease. So, having the information in this case, when you know what the environmental stimulus is, can be very helpful. For many of the conditions that we're talking about, we simply don't know what the environmental stimulus is. For example, why is the prevalence of breast cancer in women in the Bay Area higher than anywhere else in the country? Nobody knows the answer to this question. It cannot be because of genes alone. There has to be some environmental trigger that is causing the genetic predisposition to be realized.
In the absence of clear information about this delicate connection between the environments and the gene, the information alone about the genetic condition may not be entirely helpful. I mean, we have hypotheses. For example, one hypothesis that has yet to be fully proven is that so-called foreign estrogens or xenoestrogens, which are ingested through the food chain, antibiotics given to animals which we end up eating, which actually cause estrogen overload may, in part, be responsible for the higher incidence of breast cancer. Now, if that hypothesis carries any weight at all, even if it's not fully proven, one thing we could do would be to modify the amount of animal fat that we consume. And even if that isn't the final cause of the development of breast cancer, it's going to be good for us in other ways. So, that sort of hypothesis may help modify life style. But until we have a clearer idea of this interaction, I think we have to be very careful about the way we use genetic information.