Fig. 2.

While most tumor specimens have short telomeres there is heterogeneity such that some cells may have slightly longer telomeres than others. After standard radiotherapy or chemotherapy a subset of residual cancer cells often regrow and become resistant to the initial therapy. In this setting, adding a telomerase inhibitor in the maintenance or consolidation phase of treatment may prolong progression free survival. Clinical trials are in progress to test this idea in humans with non small cell lung cancer following standard doublet chemotherapy.