This lecture covers the deregulation of the R-point transition in cancer, focusing on the perturbation of pRb function and the role of various factors such as cyclins, CDK inhibitors, and alterations in cell cycle genes. It also delves into the telomere end replication problem, discussing the function of telomerase, shelterin complex, and the mechanisms involved in telomere maintenance. Additionally, it explores protein-protein interactions, epitope tagging techniques, and the yeast 2-hybrid system for detecting protein interactions.