Good News for Seniors
Seniors might have something to celebrate. Recent research indicates that while aging has been linked to a higher risk of cancer, after a certain age, the chances of developing cancer may actually start to decline.
“The implications of this study could be significant,” said Dr. Dmitri Petrov, the lead author and a professor of biology at Stanford University. He speculated that there might be positive elements of aging that could be utilized for better cancer treatments.
Typically, cancer rates sharply rise after the age of 50, peaking between 70 and 80 years old. “The traditional understanding is that as we age, harmful mutations accumulate,” Petrov noted. “Once you’ve accumulated too many, cancer can occur.” This could lead one to believe that cancer becomes almost unavoidable as we age. However, this research suggests that after a certain point, the trend may level off and even decline.
“It seems that aging can actually serve as a means of cancer suppression,” Petrov mentioned. The reasons behind this have long puzzled scientists, but they are beginning to uncover some explanations.
In the study, Stanford researchers examined mice that were 4 to 6 months old, akin to young humans, versus those aged 20 to 21 months, when signs of aging are most evident. These weren’t just any mice; they were genetically engineered to develop fluorescent lung tumors after exposure to a specific inhaled gene delivery system.
After allowing time for tumor development, scientists checked the mice’s lungs 15 weeks later. Surprisingly, younger mice had developed three times the amount of cancer compared to older mice, with larger tumors as well.
“That’s an incredible finding,” remarked Dr. Monte Winslow, senior author and associate professor at Stanford. He added, “We would imagine that older animals would show greater cancer prevalence, but that wasn’t the case here.” The big question now is why aging-related molecular changes seem to hinder cancer growth.
To dig deeper, the research team disabled 25 tumor suppressor genes in the mice. These genes typically play a role in normal aging and protective measures against cancer.
They found that the impact of turning off these genes was less pronounced in older mice in comparison to younger ones when tumors were induced again. Essentially, while tumor rates increased across all age groups when these suppressors were deactivated, the hike was significantly more significant in younger mice, especially concerning particular genes.
“The inactivation of the PTEN gene was markedly more impactful in the younger mice,” said Dr. Emily Schuldiner, the lead author, who previously worked as a graduate student on the project. She highlighted that this discrepancy hints at how specific mutations affect individuals differently depending on their age, which could also influence the effectiveness of certain cancer treatments.
This is a crucial realization, considering that most animal cancer studies have centered around younger specimens. “We’re creating these animal models to ultimately develop new treatments for patients,” Winslow explained. However, he emphasized that accurately reflecting age-related behavioral changes within these models is essential for their effectiveness.
By focusing on older mice, the researchers aim to better understand how aging might provide protection against cancer, which could lead to significant advancements in human treatment strategies.
