Thanks for the interesting article, Mr X. It speaks mostly of other mushroom species containing this carcinogen, not much on agaricus bisporus. It is quite paradoxical in that these and most other mushroom species boost the immune system and prevent cancer, but at the same time contain a carcinogen? I am not concerned about this issue and hardly ever eat raw mushrooms.
As for the Champex / Odor Cleanse extract, as far as I am able to determine from the analysis on www.directfood.net/champex it is only an extract of amino acids from the mushroom. I have no idea if the carcinogen cited in your article would be in the end product powder or not. If you want to know for sure, you could email them on the directfood website. They should be able to find this out for you.