@ddljohn-- I'm not an expert on this but my sister has breast cancer and I've been doing a lot of research on natural cures.
There are a lot of stories about people in South America curing their cancer with pawpaw tree leaves. Apparently, they boil the fresh leaves and then drink the water every day for at least several months and the cancer cells die off. This extract is supposed to be far more powerful than medicines used for cancer today.
I honestly don't know why more studies are not being done on this plant when there are so many claims of its ability to cure cancer. I personally am planning to purchase some and make this for my aunt.