Toronto team finds 81 new basal-like breast cancer driver genes in living tumors

Researchers in Toronto identified 81 previously unrecognized genes associated with the growth of basal-like breast cancer, one of the most aggressive and difficult forms of the disease to treat, according to SciTechDaily covering a Nature study. The work was led by Dr. Daniel Schramek of Sinai Health and the Lunenfeld-Tanenbaum Research Institute and Dr. Khalid Al-Zahrani, formerly a postdoctoral fellow at LTRI and now at the University of Toronto Donnelly Centre. Using a gene-editing system that can both disable genes and increase their activity inside living animals, the team tested how abnormal chromosome numbers and rearrangements influence the cancer. Basal-like breast cancer, also called triple-negative breast cancer, disproportionately affects younger women of color and is frequently marked by aneuploidy, in which cells contain abnormal numbers of chromosomes or chromosome segments. Its tumors lack three receptors commonly used to classify and target other breast cancers, leaving fewer options for precision therapy. Schramek said that in many extensively researched breast cancers the five-year survival rate is around 95 percent, but in this subset drivers remain poorly known and outcomes are among the worst. Al-Zahrani developed CRISPR-KOALA, a Knockout and Activation Linked Assay that can turn some genes off while switching others on within the same mouse, allowing researchers to imitate both deletion and duplication seen in aneuploidy. The team used the system to examine more than 3,700 genes on chromosomes commonly altered in basal-like breast cancer and identified the 81 genes. Ninety percent of the newly identified genes were not detected in standard cell culture experiments. One gene, PLGRKT, emerged as an especially powerful driver that helps cancer cells survive in low-oxygen regions deep inside a tumor and supported tumor growth, making it a possible candidate for future targeted treatment research. The findings were published in Nature with the reference date 8 July 2026.