BOTTOM LINE:
- Researchers have discovered a way in which one of the deadliest and most difficult to treat breast cancers allows tumor cells to grow unchecked and how these tumors resist treatment. Specifically, they found that BRCA1-deficient cells activate CTSL which leads to lower levels of the protein 53BP1 which, in turn, allows cancer cells to grow unchecked.
- In addition, they discovered the potential for a new therapy involving vitamin D, and identified biomarkers that can help identify which patients could benefit from this therapy.
- In the future, women with triple-negative breast cancer may benefit from a treatment that includes vitamin D. As with all laboratory research, vitamin D therapy will have to be studied in a clinical trial before doctors know how safe or effective it will be.
- Researchers’ next steps will be to study molecular mechanisms behind the activation of the degradation of 53BP1 by CTSL. In addition, preclinical studies with vitamin D and cathepsin inhibitors as single agents or in combination with different drugs are underway in mouse models of breast cancers.
