Interesting. Wikipedia makes that 80% claim, citing:<p>Aschacher; Wolf; Enzmann; Kienzl (2015). &quot;ALINE-1 induces hTERT and ensures telomere maintenance in tumour cell lines&quot;. Oncogene. doi:10.1038&#x2F;onc.2015.65.<p>Aschacher et al write:
&quot;In about 80% of tumour cells, telomere maintenance is controlled by telomerase (TA), a reverse transcriptase, which adds DNA repeats onto chromosomal ends.&quot;12, 22, 23, 24, 25<p>I checked all five references and none had anything about this 80% of tumors number. It appears to be made up.