A study undertaken by Dr. Mark Heaney and colleagues at the Memorial Sloan-Kettering Cancer Center in New York published findings yesterday claiming that Vitamin C supplements may reduce the efficacy of cancer drugs including Novartis' Gleevec. Vitamin C treated human cancer cells were tested with chemotherapy drugs in lab dishes. The drugs administered killed between thirty and seventy percent less tumour cells than if the human cancer cells had not been treated with Vitamin C. The results were published in the medical research journal Cancer Research.