BRCA genetic testing may be a new norm for those at risk for breast cancer, but you may want to test for another gene when you go in for your test.
A new study has pinpointed a gene — the BCL11A — that contributes to triple-negative breast cancer development and progression. About one in five patients affected by breast cancer has triple-negative breast cancer, which is an aggressive form of the disease.
In layman’s terms, triple-negative cancer is missing three receptor proteins that respond to therapies that treat other types of cancer. The prognosis is poor, and only a handful of abnormalities in genes have been linked to this type of breast cancer.
The BRCA1 and BRCA2 genes are genes that suggest a susceptibility to breast cancer. Normally, they function to protect us against the disease; when they mutate, however, it can cause cancer.
The research was conducted in human cells and in mice at the Wellcome Trust Sanger Institute in the U.K. Scientists there examined breast cancers in about 3,000 patients. They were looking for gene changes that affect stem cells and developing tissues. Enter BCL11A, which they also found to be required for breast stem cells — the kind that are believed to trigger basal-like breast cancer upon mutation.
“Our understanding of genes that drive stem cell development led us to search for consequences when these genes go wrong,” explained Dr. Pentao Liu, a study author from the Institute, in a statement.
“BCL11A activity stood out because it is so active in triple-negative cancers,” he said. “It had all the hallmarks of a novel breast cancer gene.”
Increased BCL11A gene activity was noted in about eight out of 10 patients with basal-like breast cancer, and it was linked with a more advanced grade of tumor. In some cases where they found copies of the BCL11A gene created in the cancer, survival prospects were grim.
The finding, however, is good news — earlier detection can lead to a better prognosis.
When the researchers added an active human BCL11A gene to human or mouse breast cells, they behaved as cancer cells. When the BCL11A activity in three samples of human triple-negative breast cancer cells was decreased, they lost some characteristics of cancer cells — and they were less tumorigenic when they were tested on mice.
“By increasing BCL11A activity we increase cancer-like behavior; by reducing it, we reduce cancer-like behavior,” said Dr. Walid Khaled, a researcher from the Institute and the University of Cambridge, in a statement.
What does finding another gene matter? More targeted treatments.
“Finding a novel gene that is active in cancer should also help in the search for new treatments,” said Carlos Caldas, a director of the Cambridge Breast Cancer Research Unit at the University of Cambridge, in a statement.