There are many other alternative remedies, that can be used to treat cancer and other diseases, I don't believe that there is any reason for anyone to use either of these chemicals. IMHO the risks are too great, and as many people are self diagnosing and self treating, without even a basic knowledge of chemistry, using these toxic substances is a recipe for disaster.
I have not been able to find any credible independant evidence that either mms or mms2 are safe or effective, and wouldn't reccommend either.