Treatment resistance in triple-negative breast cancers linked to softer tissue environment Researchers at the University of California, San Francisco, have discovered that aggressive, triple-negative breast cancers (TNBCs) can evade treatment by reorganizing and softening the collagen matrix that surrounds the cancer cells. The study, which will be published April 2 in the Journal of Experimental Medicine ( JEM), shows that the softer matrix activates a signaling pathway that promotes the cancer cells' survival, and suggests that targeting this pathway could enhance the effectiveness of chemo- and radiotherapy in TNBC patients. TNBC is an aggressive type of breast cancer with worse survival rates than other forms of the disease. Because TNBC cells lack the HER2 signaling receptor and the estrogen and progesterone hormone receptors, they cannot be eliminated by drugs that specifically target these proteins. Instead, TNBC patients are normally treated with a combination of surgery and chemotherapy/radiation, but these treatments are often unable to completely eliminate the tumor, leading to local recurrence and metastasis to other tissues.