The MAIN reason I started on Grapeseed Extract back in 1995 was that the organization I was buying it from gave us a list of issues GE "attacked" and one was Cancer. And Anti-Aging.
Many other health issues have been helped since I've been taking it now 13 yrs. A big one allergies/sinus/headaches.
A gf sent me a message today about GE and leukemia being prevented.
There are many many sites and books written about GE and Cancer Prevention.