Vitamin C can prove effective in the fight for cancer prevention, but apples may be better, according to scientists from Cornell University and Seoul National Universit y. In a report published in the Lancet medical journal (vol 359, no 9301), Professor C.Y. Lee, a Cornell expert on food science and technology, and his South Korean colleagues, Ki Won Lee, Hyong Joo Lee and Kyung-Sun Kang, explain that vitamin C's anti-cancer activity is effective because it blocks the carcinogenic effects of hydrogen peroxide on intercellular communication.