Telomere length is maintained by the enzyme, telomerase, which has been linked to cellular immortality and tumour progression. However, the reasons for the high levels of telomerase found in human tumours are unknown. We have mapped the human telomerase RNA gene, (hTR), to chromosome 3q26.3 and show the hTR gene to be ampli®ed in four carcinomas, (2/33 cervix, 1/31 head and neck, 1/9 lung). In addition, increased copy numbers of the hTR locus was also observed in 97% of tumours. By in situ hybridisation, the histological distribution of high levels of hTR expression could be demonstrated in a lung tumour and its metastasis with hTR ampli®cation. These results are the ®rst report of genetic alterations involving a known component of telomerase in human cancer. Indeed, it is also the ®rst report of the ampli®cation of a speci®c locus within the chromosome 3q region frequently subject to copy number gains in human tumours. In addition, we also show for the ®rst time the histological distribution of the RNA component of telomerase in human tumours.

No abstract

No abstract