PRKDC and brain neoplasm: Interestingly, there was significant reduction in the level of DNA-PKcs activity in dual inhibited brain tumour cells (Figure 6A) leading to increased growth retardation in MO59K (65%), KNS60 (61%) and ONS76 cells (57%) (Figure 6B).It is suggested that prolonged exposure to telomerase inhibitors may also give rise to population of cells that shows resistance to telomerase inhibition therapy.