We intend to develop oligonucleotides to suppress the reactivation of reverse transcriptase telomerase (TERT) in cancer cells with mutations in the TERT promoter (mutTERTp). These are often found in various tumors (e.g.: thyroid, liver, skin, central nervous system). The strategy comprises the production of oligonucleotide conjugates specifically directed at cancer cells as a therapeutic for aggressive tumors.