Of the 14 million cancer survivors in the United States, a significant number experience a serious side effect called chemotherapy-induced cognitive impairment (CICI). While easily recognized, little is known about the etiology of this condition, also known informally as “chemo brain.” CICI can significantly reduce patients’ quality of life with serious, even devastating, symptoms such as memory lapses, difficulty concentrating, negative impacts on multitasking, confusion and fatigue.