In a recent study, a research team from Saint Louis University uncovered a molecular pathway that contributes to triple-negative breast cancer - an often deadly and treatment-resistant form that tends to strike down younger women.
Women who are born with a gene mutation known as BRCA1 are at higher risk than normal for developing breast and ovarian cancers. These tumors are frequently the triple-negative type - and although chemotherapy is the most effective treatment, it comes with very unpleasant and serious side effects.
This study shows that activation of a novel pathway not only allows tumor cells to grow unchecked, but also makes them less sensitive to normal therapies. Importantly, vitamin D appears to play a role in turning off this pathway and consequently may be a safe, inexpensive strategy to fight these types of tumors.
Human cells employ complex mechanisms to protect genetic information and to ensure that none of their damaged DNA is passed on to their daughter cells. They have built-in checkpoints to slow down or completely stop their own growth if necessary. Damaged DNA is usually the result of the loss of these checkpoints and often leads to cancer.
BRCA1 is a well-known tumor suppressor gene and women who carry mutations in this gene have a high risk of breast and ovarian cancer.
The research team found that treatment of tumor cells lacking BRCA1 with vitamin D leads to more DNA instability and reduced growth in these cells. Further, vitamin D restores their sensitivity to standard therapies. This suggests that a combination of vitamin D and standard therapies could be a powerful novel therapy to treat breast cancers with a poor prognosis, such as triple-negative breast cancer.
Finally, the research team found clear biomarkers that are likely to be very useful in the future for customizing breast cancer therapies, along with identifying patients who might benefit the most from vitamin D treatment.
In other words - these researchers appear to have discovered why a deadly, treatment-resistant breast cancer grows unchecked. Their research further suggests that vitamin D may restore the sensitivity of these tumor cells to standard therapies.