Non-Hodgkin's Lymphoma: Molecular Features of B Cell Lymphoma

Interphase fluorescence in situ hybridization is more sensitive than BIOMED-2 polymerase chain reaction protocol in detecting IGH-BCL2 rearrangement in both fixed and frozen lymph node with follicular lymphoma

The detection of t(14;18)(q32;q21) is advisable for the diagnosis of follicular lymphoma (FL). In 51 patients with FL, we evaluated the applicability and sensitivity of interphase fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) using commercially available reagents. In 23 patients, only a formalin-fixed lymph node was available. In 28 patients, both frozen and formalin-fixed lymph nodes were evaluated. Fluorescence in situ hybridization was found to be 100% applicable whatever the material type. With the use of IGH-BCL2 dual-fusion, dual-color probes, t(14;18) translocation was detected in 47 (92%) of 51 FL cases with concordant results between isolated nuclei (n = 41) and frozen cytologic imprints (n = 28). Twenty-two IGH-BCL2-positive cases were also studied on fixed sections with BCL2 split signal probes showing a BCL2 split in all. Conversely, no BCL2 split was observed in IGH-BCL2-negative cases (n = 4). Owing to DNA degradation as assessed by the failure of control genes amplification, the applicability of PCR was found to be 76% in fixed lymph nodes (n = 51). After exclusion of the 12 noninformative cases, the BIOMED-2 protocol allowed the detection of an IGH-BCL2 fusion in 25 (64%) of 39 fixed specimens with 11 PCR-negative (31%) of 36 FISH-positive cases. Even on frozen material with 100% applicability, the amplification of a BCL2-JH breakpoint was achieved in only 20 (71%) of 28 cases with 5 PCR-negative (20%) out of 25 FISH-positive cases. Therefore, FISH was found superior to PCR (using BIOMED-2 protocol) in detecting IGH-BCL2 fusion. Finally, FISH individualized 4 IGH-BCL2-negative FL cases without specific histopathologic features. With the use of split signal DNA probes, 1 case showed a trisomy of the BCL2 locus and another displayed BCL6 and IGH breakpoints that would suggest a t(3;14). Whether such IGH-BCL2-negative cases are characterized by alternative oncogenetic pathways remains to be determined.

Targeting endogenous inhibitors of apoptosis for treatment of cancer, stroke and multiple sclerosis

The inhibitor of apoptosis (IAP) genes have emerged as probably the most important intrinsic regulators of apoptosis. The members of the IAP family are highly conserved in evolutionarily distant species and perform the critical role of binding to and inhibiting distinct caspases. This inhibition is mediated by discrete baculoviral IAP repeat domains that, in a domain-specific manner, inhibit either the initiator or executioner caspases. As such the function of IAPs lies at the very centre of virtually all apoptotic pathways. Since many, if not most, human pathologies involve aberrant apoptosis, the modulation of IAP levels or their activity offers huge therapeutic potential for treatment of various disorders. Indeed, available data suggest that the therapeutic downregulation of IAPs by antisense targeting or their adenovirally-mediated overexpression, can in fact be used to successfully modulate cell death.