Senior author Daniel Gottschling, Ph.D., a member of Fred Hutchinson's Basic Sciences Division, and first author Michael McMurray, a graduate student in Gottschling's laboratory, have found striking similarities between humans and simple baker's yeast with regard to the changes their genes undergo as they age.
"While yeast don't get cancer, they do have one of the major hallmarks of malignancy, which is genetic instability," Gottschling said. "We found a similar thing in yeast that has been seen in humans: genetic instability shoots up dramatically in the middle to late stage of life."
When yeast cells hit the equivalent of late-middle age, the Fred Hutchinson researchers discovered they experience a sudden, 200-fold surge in the production of genetic changes typically manifested as loss of heterozygosity, or LOH, a condition characterized by missing or mutated chromosomes. This finding suggests that the yeast Saccharomyces cerevisiae, a simple, single-celled organism, may be an ideal model for understanding the complexities of age-related cancer development in humans.
"Yeast gives us, for the first time, the potential for not only understanding the principles of what's going on mechanistically but also which molecules might be relevant to the process of age-related cancer development," Gottschling said.
Aging indeed is a potent carcinogen. Consider these statistics from the American Cancer Society: Nearly 80 percent of cancers are diagnosed after age 55. After reaching late-middle age, men face a 50 percent chance of developing cancer and women have a 35 percent chance. No one knows why cancer typically surfaces later in life, although a multitude of scientific theories abound. "T
Contact: Kristen Lidke Woodward
Fred Hutchinson Cancer Research Center