Cancer is a leading cause of death in California. Many cancers resist current therapies due to therapy-resistant cancer stem cells (CSCs). A team at UCSD is testing an antibody therapy called cirmtuzumab in a clinical trial study to treat a blood cancer, Chronic Lymphocytic Leukemia (CLL). The antibody recognizes and attaches to a protein on the surface of cancer stem cells. This attachment disables the protein which slows the growth of the leukemia and makes it more vulnerable to anti-cancer drugs. The team is also testing cirmtuzumab in combination with an approved cancer fighting drug called ibrutinib, to target can- cer stem cells in a separate clinical trial. The aim is that combining cirmtuzumab with ibrutinib will improve cancer remission and long-term cancer control in patients.