CRISPR-KOALA In Vivo Screen Pinpoints 81 Aneuploidy Drivers in Basal-Like Breast Cancer

Researchers led by Schramek and Al-Zahrani at Sinai Health adapted CRISPR editing for simultaneous knockout and activation within intact mammary tissue. The screen targeted chromosomal segments recurrently altered in triple-negative basal-like tumors, which lack ER, PR, and HER2 and carry five-year survival near 70 percent versus 95 percent in receptor-positive subtypes. PLGRKT emerged as the strongest hit, promoting survival under hypoxia via an uncharacterized mechanism.

Standard two-dimensional screens miss microenvironment-dependent dependencies; 90 percent of the 81 genes showed no phenotype in vitro yet drove tumor formation when tested in vivo. This gap explains why decades of cell-line work yielded few actionable targets for basal-like disease, which disproportionately affects younger women of African ancestry.

The work remains preclinical. Orthotopic mouse models capture tissue architecture better than cell lines but still omit human stroma, immune editing, and long-term clonal dynamics. Next required steps are orthogonal validation in patient-derived xenografts, functional assays of top candidates, and assessment of pharmacologic tractability before any clinical translation.