ABSTRACT
Activation of telomerase reverse transcriptase (hTERT) is essential for unlimited cell growth and plays a critical role in tumorigenesis. We investigated hTERT gene expression in 134 B-cell chronic lymphocytic leukemia (B-CLL) cases and evaluated its prognostic value with other prognostic markers (IgVH mutation status, CD38 and ZAP-70 expression). Real-time PCR assays to quantify either all hTERT transcripts (AT) or only the full length (FL) transcript encoding the functional protein were developed. hTERT-AT levels strongly correlated with hTERT-FT levels (r=0.743, P<0.0001); both inversely correlated with the percentage of IgVH mutation (P<0.005) and were significantly higher in unmutated than in mutated cases (P=0.004 and P=0.001, respectively). The hTERT values which best discriminated between the unmutated and mutated IgVH cases were 150 and 40 copies for hTERT-AT and hTERT-FL, respectively. Using these cut-off values, there was a significant difference in the survival of patients with high or low hTERT levels (P<0.0001). Unmutated cases with low hTERT levels had an overall survival close to mutated cases with high hTERT levels. Thus, this work identifies hTERT-RNA level as a new prognostic marker in B-CLL, and may be used to identify previously unrecognized patient groups with the same IgVH mutation status and different disease outcomes.
