Telomerase activity in chronic lymphoproliferative disorders of B-cell lineage

The progressive shortening of telomeres at each cell division is a key mech anism in controlling cell proliferative capacity, The activation of telomer ase, a reverse transcriptase that extends telomere length, potentially lead s to unlimited cell proliferation, and is believed to play a critical role in the neoplastic process. High levels of telomerase activity have been dem onstrated in almost all solid tumours, however. little data is available co ncerning its expression in chronic B-cell neoplasms. By using a quantitativ e polymerase chain reaction-based method we quantified telomerase activity in normal B lymphocytes, and in various B-cell malignancies, including chro nic lymphocytic Leukaemia (CUI, mantle cell lymphoma (MCL) and hairy cell l eukaemia (HCL). Compared to normal B cells, which expressed very low levels of telomerase activity malignant cells from most of the patients showed a significant increase in telomerase activity, with highest values observed i n HCL samples. Moreover, among the CLL and HCL cases, significantly higher levels of telomerase activity were found in patients with progressive disea se at 1 year follow-up versus patients with stable disease, These data sugg est that telomerase activity might correlate with disease progression.