Folic Acid Supplementation

After reading extensively on many different supplements and their possible benefit for cancer patients, I am left confused about one in particular. There is research available that suggests that high dose (2.5 mg/daily) folic acid can help fight many cancers, including breast cancer. On the other hand, there is also some evidence that cancer cells need large amounts of folic acid to survive, and even have extra large numbers of folate receptors on their surface. Apparently, evidence suggests that folate deficiency can impede cancer cell growth. However, higher doses of folic acid show even further inhibition of malignant cell growth. Oddly enough, the anti-cancer drug methotrexate supposedly attacks the folate use of malignant cells as it's mechanism of action. I wish there could be some clear explanation of the latest research in the area of vitamin and mineral supplementation in the treatment of cancers, as I would hate to find out after the fact that I had been doing anything to aid the cancer.