Chronic lymphocytic leukemia is the most common leukemia in adults, yet its earliest warning sign often hides in plain sight. Monoclonal B cell lymphocytosis, or MBL, affects millions of adults who may never know they carry this precursor to CLL. In this episode of Tomorrow's Cure from Mayo Clinic, host Cathy Wurzer talks with hematologist Dr. Sameer Parikh and researchers Dr. Susan Slager and Dr. Gerald Marti about how MBL was discovered, what it reveals about inherited risk, and why it