Telomerase plays a pivotal role in cellular immortality and tumorigenesis. Its 
activity is normally not detectable in most somatic cells while it is 
reactivated in the vast majority of cancer cells. Therefore, inhibition of 
telomerase has been viewed as a promising anticancer approach due to its 
specificity for cancer cells. Studies so far have shown that telomerase 
inhibition can inhibit the proliferation of cancer cells or cause apoptosis 
while it has no effect on most normal cells. Strategies currently being applied 
to induce telomerase inhibition target virtually all of the major components of 
the ribonucleoprotein holoenzyme and related cell signal pathways that regulate 
its activity. These strategies include inhibition of telomerase through 
targeting at the telomerase reverse transcriptase (TERT) catalytic subunit, the 
telomerase RNA (TR) component, and associated proteins. Other strategies have 
been developed to target the proteins associated with telomerase at the 
telomeric ends of chromosomes such as tankyrase. The specific mechanisms that 
mediate those inhibition effects include small molecules, antisense RNA, and 
ribozymes. Although the beneficial evidence of telomerase inhibition is obvious, 
limitations of strategies remain to be resolved to increase the feasibility of 
clinical application. This analysis will summarize recent developments of 
strategies in telomerase inhibition.