Hi, all. My understanding of COQ10 is that it does have some anticancer properties, but the extent of those properties has not been definitively assessed or described. The problem with "miracle" cures is that spontaneous remissions and cures are known to occur, and it is difficult to verify when a remission is spontaneous, or is caused/assisted by the taking of supplements in the absence of a broad placebo-based study.
One thing that is known for sure about COQ10 is that this is depleted by almost every chemo regimen. Supplementation is needed to maintain it at normal levels following administration of chemotherapy. It is controversial as to whether it should be taken during active chemo, but is generally regarded as OK to take during the weeks of between cycles.
My favorite book about supplements is "Beating Cancer through Nutrition" by Patrick Quillan. He was the head nutritionist at Cancer Treatment Centers for 10 years. The book is like an encylopedia of supplements, vitamins and diets. There are tons of footnotes, so you can verify the claims by reading the original articles cited in mainstream medical journals.
I love supplements, and take a whole bunch of them, including COQ10, milk thistle extract, alpha lipoic acid, selenium, resveratrol, and rice tocotrienols.
To each his own, and good luck to all!
Violarob in Texas