Telomere length is maintained by the ribonucleoprotein enzyme telomerase. T
he RNA component of telomerase (hTR) is widespread, and only the expression
of the mRNA encoding the catalytic protein subunit (hTRT) is correlated wi
th telomerase activity. We have studied the level of expression of hTR and
hTRT in four different models of neoplastic and preneoplastic lesions using
the RT-PCR method on RNA extracted from paraffin-embedded human tissues af
ter microdissection, The expression at the mRNA level was compared with the
enzymatic activity. Our results suggest that there may be a reciprocal con
trol at the transcriptional level of the expression of hTRT and hTR which i
n turn is associated with tumor progression. (C) 1999 Federation of Europea
n Biochemical Societies.