Because previous studies demonstrated that the upregulation of telomerase expression and activity following telomerase reverse transcriptase (TERT), promoter mutations comprises the main mechanism through which telomere length is restored (18), we used the telomerase inhibitor BIBR1532 to disrupt telomere maintenance and tested the individual and combinatorial effects of BIBR1532 and TMZ on two glioma cell lines, U87MG and U118MG, with TERT promoter mutations. Here, TERT is linked to glioma.