3D Telomere Dynamics In Hodgkin's Lymphoma

Innovative 3D telomere q-FISH allows a mechanistic understanding of the transition from the mononuclear Hodgkin (H) to the multinuclear Reed-Sternberg (RS) cell in in Hodgkin's lymphoma (HL) derived cell lines and diagnostic patient biopsies (Leukemia. 2009; 23:565-573). In RS-cells the telomere protecting shelterin complex appears to be disrupted and deregulation of DNA repair mechanisms is observed. These changes occur in both, classical EBV negative and EBV-associated, LMP1 expressing HL (Lab Invest. 2010; 90:611-619). However, it is not known whether the 3D telomere profile at diagnostic biopsy is different in patients entering rapid remission after initiation of standard chemotherapy (ABVD) compared to that-one of patients with relapsing or refractory disease. In order to answer this question we analyzed by 3D telomere q-FISH diagnostic biopsies of HL patients entering rapid complete remission and compared them to diagnostic biopsies of patients with relapsing or refractory disease.

Rapid remission group (after 1–4 cycles of ABVD): 7 diagnostic biopsies of 7 patients, 19–57 years old, 5 male, 3 LMP1 expressing, 4 nodular sclerosis subtype, 3 mixed cellularity subtype, stages IA, IIA, IIIA × 2, IIIB x2, IVA. Relapse group: 7 diagnostic biopsies of 4 patients, 40–77 years old, 2 male, 1 LMP1 expressing, 3 nodular sclerosis subtype, 1 mixed cellularity subtype, stages IIA bulky, IIIB × 2, IVB; first remission after 6–8 cycles of ABVD in 3 patients, 1 patient died from progressive disease after 11 months. 3D telomere q-FISH was performed as described (Lab Invest. 2010; 90:611-619) and statistical analysis was performed using nested or two-way analysis of variance.

Bi- or multinuclear RS-cells of all patients from both groups showed a significant increase of very short telomeres and telomere aggregates when compared to the mononuclear precursor H-cells. However, most importantly, all diagnostic biopsies of the relapse group contained a very high percentage of very small telomeres, including so-called “t-stumps”, in both, H-cells (76,8 ± 11,8%) and RS-cells (87,9 ± 7,3%). Compared to the percentage of very small telomeres identified in both, H-cells (33,7 ± 9,4%) and RS-cells (54,6 ± 15,0%) of the rapid remission group, this increase is highly significant (p <0.001). Moreover, analogous findings are observed for the number of telomere aggregates. In the relapse group the average numbers of telomere aggregates per cell were 4,3 ± 2,4 aggregates per H-cell and 5,4 ± 3.0 aggregates per RS-cell, compared to 1,2 ± 0,7 aggregates per H-cell and 3,3 ± 1,1 aggregates per RS-cell in the rapid remission group.

The 3D nuclear telomere organization of H- and RS- cells in diagnostic biopsies of relapsing or refractory HL is characterized by both, H- and RS-cells with abundant “t-stumps” and numerous telomere aggregates. Very short telomeres, including t-stumps, and telomere aggregates, both, are characteristics of aggressiveness in cancer biology (Mol Cell. 2007;28:315-327; J Cell Biochem. 2010; 109:1095-1102). Thus, H- and RS-cells of refractory or relapsing HL show significant differences in the 3D telomere dynamics already at first, diagnostic biopsy when compared to H- and RS-cells of HL entering rapid remissions.

No relevant conflicts of interest to declare.