A study published this last week in the Journal of Cell Biology reports that researchers have uncovered a molecular pathway that contributes to triple-negative breast cancer, a deadly and treatment resistant form of cancer that often occurs in young women. And more yet, vitamin D might be involved in this molecular pathway. A molecular pathway is a series of actions among molecules in a cell that lead to a change in that cell.
Lead author Susan Gonzalo, PhD, Assistant Professor of Biochemistry and Molecular Biology at Saint Louis University and colleagues also identified vitamin D as a possible new cancer therapy, in addition to discovering three biomarkers that will help identify patients who may benefit from the new treatment.
Triple-negative breast cancers are harder to treat than any other type of breast cancer. Women born with the BRCA1 gene are at increased risk of developing triple-negative breast and ovarian cancers. To date, chemotherapy is the most effective and commonly used treatment of triple-negative breast cancer, but it has profound side effects. The understanding of this new pathway will help develop less toxic and invasive treatment options.
The researchers found that activation of the discovered pathway allows tumor cells to continue growing unchecked. This explains why these cancers are less responsive to typical treatment. The authors report that vitamin D can play a role in turning off this pathway.
Finally, the researchers found that high levels of nuclear CTSL and low levels of 53BP1 and nuclear vitamin D receptors are markers that identify certain triple-negative breast cancers. CTSL plays a large role in tumor invasion and the spread of cancer to other areas of the body. 53BP1 is involved in DNA damage response. So, it makes sense that high levels of CTSL (indicates tumor invasion) and low levels of 53BP1 (responds to DNA damage) would suggest the existence of cancer. These biomarkers could allow doctors to customize breast cancer treatment for the patient.
Researchers are currently studying the effectiveness of vitamin D alone or in combination with different treatments in mice with breast cancer. Of course, further clinical trials will need to be conducted before recommendations are made, but nonetheless, the research is a breakthrough in the understanding of breast cancer treatment.