 Maintaining telomere length is critical for cell immortalization , a key feature of cancer . Most cancers maintain telomeres by <unk> telomerase . However , in several types of human cancer , a BIR @-@ like pathway helps to sustain some tumors by acting as an alternative mechanism of telomere maintenance . This fact has led scientists to investigate whether such recombination @-@ based mechanisms of telomere maintenance could thwart anti @-@ cancer drugs like telomerase inhibitors . 
