Yoshinori Ohsumi, winner on Monday of the Nobel Prize in physiology or medicine, never dreamed that his study of yeast would someday "serve any practical purposes" when he started it alone 28 years ago.

But he never doubted the importance of such fundamental scientific studies, a belief that eventually achieved great progress in the life sciences that helped unlock key mysteries of autophagy, the process of removing unwanted proteins within a cell.

"I want to emphasize one thing here. When I started this study, I wasn't convinced that this would lead to (answers for) any questions such as those concerning cancer and human longevity," Ohsumi, an honorary professor at the Tokyo Institute of Technology, said during a news conference at the university Monday evening.