[Gene expression profiling by suppression subtractive hybridization (SSH): a example for its application to the study of lymphomas].

Suppression subtractive hybridization (SSH) was used to isolate genes that were differentially expressed in anaplastic lymphoma kinase (ALK)-positive and ALK-negative anaplastic large cell lymphoma. In addition, this approach was applied to Hodgkin's disease cases with different clinical outcomes. SSH combines a normalization step that equalizes the abundance of cDNAs within the sequences to be tested and a subtraction step that excludes the common sequences between the target and the control.

Telomerase activity might persist in the human thymus throughout life.

Telomerase activity has been demonstrated at low levels in peripheral blood lymphocytes but at high levels in germinal centre B cells and thymocyte subpopulations. This study shows that telomerase is activated in the normal human thymus at different times of life. Telomerase activity was detected in thymic protein extracts from two newborn babies and from a 12 year old boy, as well as in extracts from two of six adult patients.

Telomerase activity in Hodgkin's disease.

Telomerase activity has been demonstrated in various types of cancers including lymphoid neoplasms. The tumour specificity of telomerase activity has been a subject of debate since the description of detectable enzymatic activity in non neoplastic tissues. We and others have demonstrated that such activity was present in non Hodgkin's lymphomas as well as in reactive hyperplastic lymph nodes and tonsils.

[Techniques for detection of telomerase activity in tissue samples. Diagnostic and prognosis importance].

Telomerase activation has been shown to be an almost universal property of malignant tumors evoking its role in the immortalisation process. We used the recently described sensitive and rapid detection assay called telomeric repeat amplification protocol (TRAP) to detect telomerase activity in neoplastic and non neoplastic tissues. Human telomerase is a ribonucleoprotein which functions as a telomere terminal transferase by adding multiple repeats of the TTAGGG hexamer at the 3'-OH ends of either telomeres or oligonucleotide specifically designed for the TRAP assay.

Telomerase activity in human thyroid carcinomas originating from the follicular cells.

Telomerase activity is known to be absent from most normal and well-differentiated tissues, although being detectable in the vast majority of malignant tumors. An increasing number of reports demonstrate that telomerase may be activated in benign tumors, such as adenomas. We have investigated a series of normal and neoplastic thyroid tissues for the presence of telomerase activity.

Telomerase activity in reactive and neoplastic lymphoid tissues: infrequent detection of activity in Hodgkin's disease.

We used the recently described sensitive and rapid detection assay called telomeric repeat amplification protocol (TRAP) to detect telomerase activity in lymphoblastoid (n = 5) and lymphoma cell lines (n = 7), hyperplastic lymph nodes (n = 6) and tonsils (n = 5), and tissues involved by non-Hodgkin's lymphoma (NHL) (n = 43) and Hodgkin's disease (HD) (n = 14). Clearly evident telomerase activity was found in all lymphoblastoid and lymphoma cell lines, and in 34 of 43 cases (80%) of NHL. These results were expected because of the proliferative and immortal nature of the cell lines and most malignant cells.