Monoallelic TP53 inactivation is associated with poor prognosis in chronic lymphocytic leukemia: results from a detailed genetic characterization with long-term follow-up.

The exact prognostic role of TP53 mutations (without 17p deletion) and any impact of the deletion without TP53 mutation in CLL are unclear. We studied 126 well-characterized CLL patients by direct sequencing and DHPLC to detect TP53 mutations (exons 2-11). Most patients with 17p deletions also had TP53 mutations (81%). Mutations in the absence of 17p deletions were found in 4.5%. We found a shorter survival for patients with TP53 mutation (n = 18; P = .002), which was more pronounced when analyzed from the time point of mutation detection (6.8 vs 69 months, P < .001). The survival was equally poor for patients with deletion 17p plus TP53 mutation (7.6 months, n = 13), TP53 mutation only (5.5 months, n = 5), and 17p deletion only (5.4 months, n = 3). The prognostic impact of TP53 mutation (HR 3.71) was shown to be independent of stage, VH status, and 11q and 17p deletion in multivariate analysis. Serial samples showed evidence of clonal evolution and increasing clone size during chemotherapy, suggesting that there may be patients where this treatment is potentially harmful. TP53 mutations are associated with poor sur-vival once they occur in CLL. The de-monstration of clonal evolution under selective pressure supports the biologic significance of TP53 mutations in CLL.

Short telomeres are associated with genetic complexity, high-risk genomic aberrations, and short survival in chronic lymphocytic leukemia.

Telomere length is associated with mutation status of the immunoglobulin heavy chain variable (IGHV) gene and clinical course in B-cell chronic lymphocytic leukemia (B-CLL). In a B-CLL cohort of 152 patients, we analyzed telomere length, genomic aberrations, IGHV mutation status, CD38 and ZAP-70 expression to study the prognostic impact and associations among these factors. An inverse correlation existed between telomere length and IGHV homology (P < .001), CD38 (P < .001), and ZAP-70 expression (P = .01). Patients with telomere lengths below median (ie, "short telomeres") and above median (ie, "long telomeres") had similar incidences of genomic aberrations (74% vs 68%), 13q- (57% vs 49%), and +12q (5% vs 12%). In contrast, 13q- as a single aberration was more frequent in patients with long telomeres (51% vs 21%; P = .006), whereas 11q- (27% vs 9%; P = .014), 17p- (17% vs 0%; P < .001), and 2 or more genomic aberrations (39% vs 8%; P < .001) were more frequent in patients with short telomeres. Compared with patients with long telomeres, treatment-free survival (TFS) and overall survival (OS) was significantly shorter (P < .001 and P = .015, respectively) in the group with short telomeres, and telomere length was an independent prognostic indicator for TFS. These observations have biological and prognostic implications in B-CLL.

Clonal evolution in chronic lymphocytic leukemia: acquisition of high-risk genomic aberrations associated with unmutated VH, resistance to therapy, and short survival.

In chronic lymphocytic leukemia (CLL), the acquisition of new genomic aberrations during the disease course (clonal evolution) is thought to be an infrequent phenomenon but comprehensive analyses are limited. Genomic aberrations were analyzed by fluorescence in situ hybridization (FISH) at various time points during the disease course of 64 CLL patients. Results were correlated with the mutation status of the immunoglobulin heavy-chain variableregion genes (VH) and clinical characteristics. Following a median observation time of 42.3 months (range 23.2-73) after first genetic study, 11 out of the 64 (17%) patients showed clonal evolution with the following newly acquired aberrations: del(17p13) (n=4), del(6q21) (n=3), del(11q23) (n=2), +(8q24) (n=1), and evolution from monoallelic to biallelic del(13q14) (n=3). Interestingly, clonal evolution only occurred among cases with unmutated VH status. The group with clonal evolution showed a higher rate of progression in Binet stage (82% vs. 28%), a possibly greater need for treatment (91% vs. 62% previously untreated patients received their first therapy), and a higher hazard risk of death (HR = 2.97, 95% CI 1.40-6.27, p=0.004) in multivariable analysis. The estimated median survival time after the occurrence of clonal evolution was 21.7 months. Expansion of the clone with del(17p13) was observed in all patients during treatment, indicating in vivo resistance to therapy. In multivariable Andersen-Gill regression analysis, clonal evolution was identified as an independent prognostic factor for overall survival. Clonal evolution only occurred in CLL with unmutated VH indicating to karyotypic instability as a pathomechanism. Acquisition of genomic aberrations was associated with poor outcome based on multivariable analysis. In vivo resistance to chemotherapy of CLL clones with del(17p13) emphasizes the need for alternative treatment approaches in these patients.

Overexpression of the paternally expressed gene 10 (PEG10) from the imprinted locus on chromosome 7q21 in high-risk B-cell chronic lymphocytic leukemia.

We report high expression of the maternally imprinted gene PEG10 in high-risk B-CLL defined by high LPL mRNA expression. Differential expression was initially identified by microarray analysis and confirmed by real time PCR in 42 B-CLL patients. mRNA expression ranged from 0.3- to 375.4-fold compared to normal peripheral blood mononuclear cells (PBMNC). Expression levels in CD19+ B-CLL cells were 100-fold higher than in B-cells from healthy donors. PEG10 expression levels in B-CLL patient samples remained stable over time even after chemotherapy. High PEG10 expression correlated with high LPL expression (p=0.001) and a positive Coombs' test (p=0.04). Interestingly, similar expression patterns were observed for the neighbouring imprinted gene sarcoglycan-epsilon (SGCE). Monoallelic expression and maintained imprinting of PEG10 were found by allele- or methylation-specific PCR. The intensity of intracellular staining of PEG10 protein corresponded to mRNA levels as confirmed by immunofluorescence staining. Short term knock-down of PEG10 in B-CLL cells and HepG2 cells was not associated with changes in cell survival but resulted in a significant change in the expression of 80 genes. However, long term inhibition of PEG10 led to induction of apoptosis in B-CLL cells. Our data indicate (i) a prognostic value of PEG10 in B-CLL patients; (ii) specific deregulation of the imprinted locus at 7q21 in high-risk B-CLL; (iii) a potential functional and biological role of PEG10 protein expression. Altogether, PEG10 represents a novel marker in B-CLL.

Autologous graft-versus-host disease-like syndrome after an alemtuzumab-containing conditioning regimen and autologous stem cell transplantation for chronic lymphocytic leukemia.

A high incidence of autologous graft-versus-host-disease (auto-GVHD) was observed after an alemtuzumab-containing conditioning regimen and autologous stem cell transplantation (auto-SCT) for chronic lymphocytic leukemia (CLL). Skin rash developed in almost all surviving patients (87%). In 7 patients (58%), a diagnosis of auto-GVHD was made (compared with 0% after TBI/Cy; P = .01). All patients with auto-GVHD required immunosuppression, and 3 of 7 were hospitalized because of GVHD. The median duration of GVHD was 517 days (range, 60-867 days). Auto-GVHD was associated with an abnormally high CD4/CD8 ratio because of severe depletion of CD8(+) T cells, pointing to a potential pathomechanism. High non-relapse-related mortality led to the discontinuation of the trial. Current results do not support the use of high-dose alemtuzumab combined with total body irradiation (TBI) and autologous stem cell transplantation (auto-SCT). However, the addition of alemtuzumab led to improved disease control at the molecular level. Longer follow-up will show whether the GVHD-like syndrome may contribute to prolonged minimal residual disease (MRD) negativity.

Additional genetic high-risk features such as 11q deletion, 17p deletion, and V3-21 usage characterize discordance of ZAP-70 and VH mutation status in chronic lymphocytic leukemia.

PURPOSE: Immunoglobulin heavy chain variable-region (VH) gene mutation status and zeta-associated protein 70 (ZAP-70) expression are correlated in chronic lymphocytic leukemia (CLL), but their concordance is variable. The goal of this study was to elucidate additional factors potentially characterizing their discordance. PATIENTS AND METHODS: We evaluated ZAP-70 expression by flow cytometry, VH status by DNA sequencing, and genomic aberrations by fluorescence in situ hybridization in 148 CLL patients. The parameters were analyzed for their associations and their individual prognostic impact. RESULTS: ZAP-70 expression and VH mutation status were strongly associated in CLL without additional genetic high-risk-features as defined by the absence of 11q or 17p deletion and V3-21 usage (concordance 84%). In contrast, the proportion of discordant cases was significantly higher (39%), if such additional genetic high-risk features were present. Discordant cases with V3-21 usage were almost exclusively ZAP-70 positive and VH mutated (89%), whereas all but one of the discordant cases with high-risk aberrations were ZAP-70 negative and VH unmutated (92%). By multivariate regression analysis, two models were developed, which both include high-risk genomic aberrations and, alternatively, VH mutation status and V3-21 usage or ZAP-70 expression as independent outcome predictors. CONCLUSION: There were characteristic modes of discordance between ZAP-70 and VH mutation status depending on the presence or absence of additional genetic high-risk features such as 11q and 17p deletion or V3-21 usage. Although the biologic background for these findings is yet to be determined, these data have biologic and clinical implications regarding ZAP-70 as a pathogenic factor and outcome predictor, respectively.

Strikingly homologous immunoglobulin gene rearrangements and poor outcome in VH3-21-using chronic lymphocytic leukemia patients independent of geographic origin and mutational status.

We recently reported that Swedish VH3-21-using chronic lymphocytic leukemia (CLL) patients showed restricted immunoglobulin gene features and poor prognosis despite VH mutation status. To investigate this further, we analyzed the VH and VL gene rearrangements in 90 VH3-21+ patients from Sweden, Germany, Italy, United States, Finland, and Australia and correlated these data with survival and other prognostic markers. Sixty-three percent exhibited mutated VH genes and 37% unmutated VH genes. Fifty (56%) patients displayed a short and homologous heavy-chain CDR3, many of these with the amino acid motif DANGMDV. Also, a highly biased Vlambda2-14 use was evident in 72% of patients with a restricted light-chain CDR3, QVWDS(S/G)SDHPWV. Combined restricted heavy- and light-chain CDR3s were found in patients from all included countries. Although VH3-21+ CLLs have a remarkably predominant lambda expression, analyses of kappa deleting element indicated a conserved light-chain rearrangement order. The overall survival was poor in the VH3-21+ cohort (median survival, 88 months), with no significant difference in relation to mutation status or CDR3 homology. High ZAP-70 and CD38 expression was found in both mutated and unmutated VH3-21+ cases as well as a slight increase of 11q-aberrations. In summary, highly restricted B-cell receptors and worse outcome characterize VH3-21+ CLLs independent of geographic origin and mutation status.

Distinct gene expression patterns in chronic lymphocytic leukemia defined by usage of specific VH genes.

The mutation status and usage of specific VH genes such as V3-21 and V1-69 are potentially independent pathogenic and prognostic factors in chronic lymphocytic leukemia (CLL). To investigate the role of antigenic stimulation, we analyzed the expression of genes involved in B-cell receptor (BCR) signaling/activation, cell cycle, and apoptosis control in CLL using these specific VH genes compared to VH mutated (VH-MUT) and VH unmutated (VH-UM) CLL not using these VH genes. V3-21 cases showed characteristic expression differences compared to VH-MUT (up: ZAP70 [or ZAP-70]; down: CCND2, P27) and VH-UM (down: PI3K, CCND2, P27, CDK4, BAX) involving several BCR-related genes. Similarly, there was a marked difference between VH unmutated cases using the V1-69 gene and VH-UM (up: FOS; down: BLNK, SYK, CDK4, TP53). Therefore, usage of specific VH genes appears to have a strong influence on the gene expression pattern pointing to antigen recognition and ongoing BCR stimulation as a pathogenic factor in these CLL subgroups.

Evidence for distinct pathomechanisms in genetic subgroups of chronic lymphocytic leukemia revealed by quantitative expression analysis of cell cycle, activation, and apoptosis-associated genes.

PURPOSE: In patients with chronic lymphocytic leukemia (CLL), the VH mutation status and genomic aberrations (13q-, +12q, 11q-, 17p-) identify distinct prognostic subgroups. The aim was to elucidate biologic mechanisms through which these genetic markers may exert their pathogenic influence. PATIENTS AND METHODS: Twenty-four genes involved in apoptosis, cell cycle, B-cell activation, and B-cell receptor (BCR) signaling were analyzed by real-time quantitative reverse transcription polymerase chain reaction (RQ-PCR) in 82 CLL cases constituting prototypic genetic CLL subgroups as defined by the VH mutation status and the genomic aberrations 13q-, +12, 11q-, and 17p-. RESULTS: The VH mutation subgroups were characterized by a differential expression of the BCR associated genes ZAP70 and PI3K. Among the subgroups defined by genomic aberrations, there was a deregulation of candidate genes from the affected critical genomic regions such as CDK4 (up), ATM (down), and TP53 (down) in the groups +12, 11q-, and 17p-, respectively. Additionally, the genomic subgroups were characterized by a significant deregulation of cell cycle and apoptosis regulators: AKT (up) in 13q, E2F1 (up) in +12, MYC (up) and BCL-2 (down) in 17p-, and CCND3 (down) in 11q- as well as 17p-. The 17p- subgroup showed an additional down-regulation of BCR-associated genes such as SYK and PI3K. CONCLUSION: The characteristic gene expression patterns observed implicate a differential regulation of cell cycle, apoptosis, and BCR signaling in the genetic subgroups illustrating distinct pathomechanisms and are evidence for a gene dosage effect being operative in CLL. These findings link the biologic diversity and clinical heterogeneity of CLL.

Duplication of chromosome arms 9q and 11q: evidence for a novel, 14q32 translocation-independent pathogenetic pathway in multiple myeloma.

14q32 translocations [t(14q)] represent critical but not universal events in multiple myeloma (MM). Gains of chromosome arms 1q, 9q, and 11q (+1q, +9q, and +11q) have recently been identified as frequent aberrations in this disease, but their pathogenetic significance remains unclear. We studied a series of 108 MM patients using fluorescence in situ hybridization and DNA probes mapping to chromosome bands 1q21, 9q34, 11q25, 13q14, and 14q32. Three subsets of tumors were defined: (1) MM+/+ (detection of +9q and +11q; 43.5% of cases), (2) MM+/- (+9q or +11q; 21.3%), and (3) MM-/- (neither +9q nor +11q; 35.2%). The incidence of t(14q) was significantly different in these subgroups: 23% in MM+/+, 56% in MM+/-, and 89% in MM-/-. Deletion of 13q (13q-) also was significantly less frequent in MM+/+ (23%) than in MM+/- and MM-/- (36% and 63%, respectively). The nonrandom distribution of chromosomal aberrations in the present series of MM tumors points to a novel, 14q32 translocation-independent pathogenetic pathway in plasma cell neoplasms.

Graft-versus-leukemia activity may overcome therapeutic resistance of chronic lymphocytic leukemia with unmutated immunoglobulin variable heavy-chain gene status: implications of minimal residual disease measurement with quantitative PCR.

The aim of this study was to investigate if graft-versus-leukemia (GVL) activity conferred by allogeneic stem cell transplantation (allo-SCT) is effective in chronic lymphocytic leukemia (CLL) with unmutated V(H) gene status. The kinetics of residual disease (MRD) were measured by quantitative allele-specific immunoglobulin heavy chain (IgH) polymerase chain reaction (PCR) in 9 patients after nonmyeloablative allo-SCT for unmutated CLL. Despite an only modest decrease in the early posttransplantation phase, MRD became undetectable in 7 of 9 patients (78%) from day +100 onwards subsequent to chronic graft-versus-host disease or donor lymphocyte infusions. With a median follow-up of 25 months (range, 14-37 months), these 7 patients remain in continuous clinical and molecular remission. In contrast, PCR negativity was achieved in only 6 of 26 control patients (23%) after autologous SCT for unmutated CLL and it was not durable. Taken together, this study shows for the first time that GVL-mediated immunotherapy might be effective in CLL with unmutated V(H).

The prognostic impact of autologous stem cell transplantation in patients with chronic lymphocytic leukemia: a risk-matched analysis based on the VH gene mutational status.

To assess the therapeutic value of sequential high-dose therapy (SHDT) including autologous stem cell transplantation in chronic lymphocytic leukemia (CLL) we performed a risk-matched comparison between 66 patients who had undergone a uniform SHDT regimen and a database of 291 patients treated conventionally. Matching variables were age, Binet stage, IgVH (variable region of the immunoglobulin heavy chain) gene mutational status, and lymphocyte count. Forty-four pairs fully matched for all 4 variables were identified. Patient groups were well balanced for additional risk factors including adverse genomic abnormalities and CD38 expression. With an overall median follow-up time of 70 and 86 months, respectively, survival was significantly longer for the SHDT patients than for the conventionally treated patients when calculated from diagnosis (hazard ratio [HR] 0.39; P=.03 [log rank]) or from study entry (HR 0.32; P=.006). The benefit for the SHDT group remained significant when the analyses were restricted to those 58 patients who had an unmutated VH status. Cox regression analysis confirmed SHDT as independent favorable prognostic factor for survival from diagnosis (HR 0.38, P=.04) as well as from study entry (HR 0.38, P=.03). These data suggest a survival benefit for patients with poor-risk CLL receiving SHDT during the course of their disease.

VH mutation status and VDJ rearrangement structure in mantle cell lymphoma: correlation with genomic aberrations, clinical characteristics, and outcome.

Immunoglobulin variable heavy chain gene (VH) mutation status and VDJ rearrangement structure were analyzed in 141 patients with mantle cell lymphoma (MCL) and correlated with biologic and clinical characteristics; 29% of the MCLs displayed mutated VH using a 98% germline homology cutoff. Striking differences occurred in the VH mutation subgroups with respect to the use of specific V genes. Rearrangements involving V4-34 and V3-21 were almost exclusively unmutated, whereas rearrangements using V4-59 and V3-23 were typically mutated. Significant association occurred between mutated VH with shorter CDR3 lengths and the use of JH4b. V3-21 and V4-59 were involved in highly characteristic rearrangements, implying that antigen specificity might have been involved in MCL development. There was no evidence for isotype switch recombination or Bcl-6 expression in any MCL. ZAP70 expression was not different in VH-mutated or -unmutated MCL. Although the deletions 11q- and 17p- showed a balanced distribution, an overrepresentation was observed for trisomies +3q, +8q, and tetraploidy in the VH-unmutated subgroup and +12q in the VH-mutated subgroup. Clinically, mutated VH was associated with a higher rate of complete remission, but there was no correlation between VH mutation status and other clinical characteristics or overall survival.

V(H) mutation status, CD38 expression level, genomic aberrations, and survival in chronic lymphocytic leukemia.

In chronic lymphocytic leukemia (CLL), biologic risk factors such as immunoglobulin variable heavy chain gene (V(H)) mutation status, CD38 expression level, and genomic aberrations have recently been identified, but the relative prognostic impact of the individual parameters is unknown. In the current study, we analyzed V(H) mutation status by polymerase chain reaction and sequencing (n = 300), genomic aberrations by fluorescence in situ hybridization (+3q, 6q-, +8q, 11q-, +12q, 13q-, t(14q), 17p-) (n = 300), and CD38 expression by triple-color FACS (CD5, CD19, CD38) (n = 157) in a unicentric CLL cohort. The prognostic influence of V(H) mutation rate and CD38 expression level was tested by maximally selected log-rank statistics. A corrected P value (P(cor)) for a cutoff level allowing the best separation of 2 subgroups with different survival probabilities was identified at 97% V(H) homology (95% confidence interval [CI], 96%-98% homology, P(cor) <.001) and at 7% CD38 expression (95% CI, 20%-71% expression, P(cor) =.02). In univariate analyses, unmutated V(H) genes and high CD38 expression levels predicted for shorter survival times. The overall incidence of genomic aberrations was similar in the V(H) unmutated and V(H) mutated subgroups. High-risk genomic aberrations such as 17p- and 11q- occurred almost exclusively in the V(H) unmutated subgroup, whereas favorable aberrations such as 13q- and 13q- as single abnormalities were overrepresented in the V(H) mutated subgroup. In multivariate analysis, unmutated V(H), 17p deletion, 11q deletion, age, WBC, and LDH were identified as independent prognostic factors, indicating a complementary role of V(H) mutation status and genomic aberrations to predict outcome in CLL.