TERT and cancer: Most cancer cells, in contrast to normal adult somatic cells, maintain telomeres through reactivation of TERT (~90% of cancers); alternative lengthening of telomeres (ALT) is used in other cases (Shay and Bacchetti, 1997; Pandita et al., 2015; Heaphy et al., 2011; Akincilar et al., 2016b; Sharma and Chowdhury, 2022).