Women under the age of 40 who are diagnosed with early-stage breast cancer tend to have poorer relative survival rates than older women diagnosed with the condition, but why? A new study has identified a potential genetic explanation.
Researchers at the University of Southampton in the United Kingdom found that women aged 15–39 who had early-onset breast cancer possessed specific gene variations that were associated with increased disease progression.
Lead study author Dr. William Tapper — from the Faculty of Medicine at the University of Southampton — and team say that their results not only shed light on why younger women with breast cancer have lower survival rates, but they could also offer new treatment targets for the disease.
The researchers recently reported their findings in the journal Nature Communications.
Breast cancer is most common among women aged 40 and older; women under the age of 40 account for only around 4 percent of new invasive breast cancer cases in the U.S.
But while younger women are at lower risk of developing breast cancer, when they are diagnosed with the disease, their relative survival rates are lower.
Younger women are often diagnosed with breast cancer when the disease is more aggressive, which may partly explain their poorer survival. However, the new study from Dr. Tapper and colleagues suggests that certain gene variations might also play a role.
The researchers came to their findings by conducting a meta-analysis of four cohorts including a total of 6,042 women who had received a breast cancer diagnosis. Of these women, 2,315 were between the ages of 15 and 39.
The team looked at the stage of breast cancer at diagnosis, the overall survival of the women, and their gene expression profiles.
Among younger women diagnosed with early-onset breast cancer, it was found that two single nucleotide polymorphisms (SNPs) in the ADAMTSL1 gene were associated with greater risk of disease progression.
SNPs are variations in a DNA sequence that can affect how a gene functions, and this plays a role in disease.
The researchers say that this finding “suggests that unique disease mechanisms may influence survival in younger women and provide some biological insight into why younger-onset breast cancer has a worse prognosis.”
What is more, Dr. Tapper and team say that the results could pave the way to new diagnostic and treatment strategies for young women diagnosed with early-onset breast cancer.
“Our findings increase our understanding of the genes and pathways that are involved in breast cancer prognosis, and may provide new targets for the development of novel therapies.”
Dr. William Tapper
“In the short- to medium-term,” continues Dr. Tapper, “this genetic factor may be used to improve prognostic models.”
“In the long-term,” he adds, “when more is known about the mechanism underlying this association and its relationship with treatment response, it may have an influence on approaches to the most effective breast cancer treatments.”