Research description: We focus on telomere DNA synthesis in cancer cells, a biochemical reaction that all cancer cells rely on for immortality. We demonstrated that condensation of protein liquid droplets on telomeres of telomerase-free cancer cells clusters telomeres to provide templates required for homology-directed DNA synthesis. We ask how the nucleation process is regulated, how the components are recruited , how the material properties are controlled and how they contribute to telomere DNA synthesis and cancer cell growth.