Quantitative measurement of telomerase activity in lymphadenopathy: correlation with histologic features and human immunodeficiency virus-1 infection.

Telomerase is a ribonucleoprotein that uses its internal RNA component as a template for synthesis of telomeric DNA on the ends of chromosomes after each round of cell division. It is expressed in approximately 90% of all human cancers tested to date, as well as in most immortal cell lines. Recently, telomerase activity was detected in normal proliferating lymphoid tissue and in non-Hodgkin's lymphomas (NHLs) by use of the telomeric repeat amplification protocol assay, a qualitative measure of telomerase activity. In this study, we modified the assay to measure quantitatively the telomerase activity in lymph node biopsy specimens obtained from patients with lymphadenopathy. The lymph nodes either contained benign reactive changes, were involved by NHL of B-cell lineage, or were involved by Hodgkin's disease. Telomerase activity was detected in all of our samples, benign as well as malignant. The levels of activity were unaffected by the patient's human immunodeficiency virus-1 status. Although the specimens involved by NHLs showed a range in telomerase activity from low to high, the levels did not correlate strictly with the histologic grade according to the Working Formulation. All of the cases of Hodgkin's disease also expressed telomerase activity, and the levels were similar regardless of histologic subtype. Our results showed that telomerase activity was expressed in both benign and malignant lymphoproliferative processes.