Although there is justifiable optimism regarding telomerase activity and early detection of cancer, it is important to point out that there is much that remains to be understood and additional validation studies will be required before knowledge of telomerase activity will be useful in decisions regarding patient management. A key question is whether we will be able to distinguish those cancers that are going to progress from those cancers that are not by detecting telomerase activity. Molecular staging using markers such as telomerase activity in combination with other molecular markers may be particularly useful in this regard. Basic scientists and clinicians must work together if this strategy is to mature. Telomerase inhibitors in the treatment of cancer are awaited with great anticipation.