Figure 1.
Neoplastic mutations increase proliferation and accelerate telomere shortening. Once telomeres shorten critically, a cell activates a telomere maintenance mechanism (telomerase or ALT) or it will undergo cell cycle arrest, senescence and/or apoptosis. The green X’s represent chromosomes and red dots represent telomeres at each end; blue circles represent proliferating cells, while the shaded blue circle represents a cell that has exited the cell cycle. The smaller red dots represent shortened telomeres.