The Year 2001 Forum of the William Guy Forbeck Research Foundation dealt with the topic of Differentiation in Cancer Therapy. While the concept has obviously evolved to reflect scientific advances, the general idea of differentiation goes back almost 100 years. Within this framework, cancer is viewed as a disease of relatively immature cells that are occasionally dividing at an accelerated rate, but whose major defect is a decrease in the rate of cell death. The imbalance of dividing cells versus dying cells results in tumor growth that ultimately overwhelms the patient. The relative longevity of cancer cells owes to their being trapped in a prolonged state of adolescence in which their ability to grow up is blocked due to genetic abnormalities. Conceivably, drugs that could eliminate this maturation block might enable these cells to grow up, grow old, and die off. Thus, treatments that reverse this dividing vs. dying imbalance- however slightly – should over time eventually extinguish the disease.