Telomere length in mantle cell lymphoma.

Telomere shortening is of pathogenic and prognostic importance in cancers. In the present study, we analyzed telomere length in 73 mantle cell lymphoma (MCL), 55 chronic lymphocytic leukemia (CLL), and 20 normal B-cell samples using quantitative PCR (Q-PCR) to study its association with disease characteristics and outcome. Telomere length was found to be highly variable in MCL (range, 2.2-13.8 kb; median, 4.3 kb). Telomere dysfunction in MCL was evident from comparison with normal B cells (median, 7.5 kb), but had no significant association with any biologic or clinical feature. This was in contrast to CLL, in which a significant correlation of short telomeres with poor prognostic subgroups was confirmed. There was a trend toward an increased number of genomic aberrations with shortening of telomeres in MCL. No difference in survival was observed between the groups with short and long telomeres, indicating that, as opposed to CLL, telomere length is not of prognostic relevance in MCL.

[The spleen in hematologic malignancies]. / Die Milz bei hämato-onkologischen Erkrankungen.

The spleen represents a major lymphatic and hematologic organ and, as such, is frequently involved in hematologic malignancies. Splenomegaly may constitute the first clinical sign leading to the diagnosis of a hematologic malignancy. Vice versa, the presence, or suspicion of a hematologic malignancy requires investigation of the spleen. In case of splenomegaly of unknown origin, directed history, clinical examination, and laboratory testing including a complete blood count with microscopic investigation of a peripheral blood smear, frequently allow to establish a tentative diagnosis. Whenever possible, further specific testing should be based on a thorough primary evaluation to avoid unnecessary diagnostic procedures. In light of the current diagnostic options, diagnostic splenectomy can usually be avoided to establish definitive diagnosis. Indolent lymphomas (chronic lymphocytic leukaemia, hairy cell leukaemia, splenic marginal zone lymphoma) and myeloproliferative neoplasms (chronic myeloid leukaemia, polycythemia vera, essential thrombocythemia, primary and secondary myelofibrosis) are the most prevalent hematologic malignancies associated with splenomegaly. Therapeutic options are highly differentiated depending on the underlying disease. Apart from very rare exceptions, therapeutic splenectomy can usually be avoided.

SAKK 35/15: a phase 1 trial of obinutuzumab in combination with venetoclax in patients with previously untreated follicular lymphoma.

This phase 1 study evaluated safety, tolerability, and preliminary efficacy of obinutuzumab in combination with venetoclax in patients with previously untreated grade 1-3a follicular lymphoma in need of systemic therapy. Two DLs of venetoclax were evaluated with an expansion cohort at the recommended phase 2 dose. Twenty-five patients were enrolled. The recommended phase 2 dose was venetoclax 800 mg OD continuously for 6 cycles starting on day 2 of cycle 1, with obinutuzumab 1000 mg on days 1, 8, and 15 of cycle 1 and on day 1 of cycles 2 to 6, followed by obinutuzumab maintenance every 2 months for 2 years. Only 1 patient had a DLT consisting of grade 4 thrombocytopenia after the first obinutuzumab infusion. Neutropenia was the most common adverse event of grade ≥3 at least possibly attributed to study treatment. Twenty-four patients were evaluable for response after cycle 6 by computed tomography (CT) and 19 by positron emission tomography/CT (PET/CT): overall and complete response rates were 87.5% (95% CI, 67.6% to 97.3%) and 25% (95% CI, 9.8% to 46.7%) in the CT-evaluated patients and 84.2% (95% CI, 60.4% to 96.6%) and 68.4% (95% CI, 43.4% to 87.4%), respectively, in the PET/CT-evaluated patients. One-year progression-free survival was 77.8% (95% CI, 54.6% to 90.1%) and 79% (95% CI, 47.9% to 92.7%) for CT and PET/CT-evaluable patients, respectively, whereas progression-free survival at 30 months was 73.2% (95% CI, 49.8%, 87.0%) as assessed by CT and 79.0% (95% CI, 47.9%, 92.7%) by PET/CT. Despite the activity observed, our results do not support further development of the combination in this patient population. This trial was registered at www.clinicaltrials.gov as #NCT02877550.

miR-34a as part of the resistance network in chronic lymphocytic leukemia.

17p (TP53) deletion identifies patients with chronic lymphocytic leukemia (CLL) who are resistant to chemotherapy. The members of the miR-34 family have been discovered to be direct p53 targets and mediate some of the p53-dependent effects. We studied miR-34a and miR-34b/c expression in a large cohort to define their potential role in refractory CLL. While no expression of miR-34b/c could be detected, we found variable expression levels of miR-34a. miR-34a levels were up-regulated after DNA damage in the presence of functional p53, but not in cases with 17p deletion (P < .001). We found a strong correlation of low miR-34a levels with impaired DNA damage response, TP53 mutations (without 17p deletion), and fludarabine-refractory disease (also in the absence of 17p deletion). Up-regulation of miR-34a after irradiation was associated with induction of Bax and p21, but not Puma. CLL cells with reduced miR-34a expression showed increased viability after DNA damage independently of 17p status. Therefore, low expression of miR-34a in CLL is associated with p53 inactivation but also chemotherapy-refractory disease, impaired DNA damage response, and apoptosis resistance irrespective of 17p deletion/TP53 mutation. The elucidation of mechanisms underlying miR-34a regulation and overcoming its role in chemotherapy resistance warrant further study.

Gene expression factors as predictors of genetic risk and survival in chronic lymphocytic leukemia.

BACKGROUND: A variety of surrogate markers for genetic features and outcome have been described in chronic lymphocytic leukemia based on gene expression analyses. Previous studies mostly focused on individual markers and selected disease characteristics, which makes it difficult to estimate the relative value of the novel markers. Therefore, in the present study a comprehensive approach was chosen investigating 18 promising, partly novel expression markers in a well characterized cohort of patients with long clinical follow-up and full genetic information (IGHV status, genomic abnormalities). DESIGN AND METHODS: Expression markers were evaluated using real-time quantitative reverse transcriptase polymerase chain reaction in CD19(+)-purified samples from 151 patients. Multivariate analyses were performed to test the markers' ability to identify patients at genetic risk and as prognostic markers in the context of established prognostic factors. RESULTS: For individual markers, ZAP70 expression provided the highest rate (81%) of correct assignment of patients at genetic risk (IGHV unmutated, V3-21 usage, 11q- or 17p-), followed by LPL and TCF7 (76% both). The assignment rate was improved to 88% by information from a four-gene combination (ZAP70, TCF7, DMD, ATM). In multivariate analysis of treatment-free survival, IGHV mutation status and expression of ADAM29 were of independent prognostic value besides disease stage. With regards to overall survival, expression of ATM, ADAM29, TCL1, and SEPT10 provided prognostic information in addition to that derived from clinical and genetic factors. CONCLUSIONS: Gene expression markers are suitable for screening but not as surrogates for the information from genetic risk factors. While many individual markers may be associated with outcome, only a few are of independent prognostic significance. With regard to prognosis estimation, the genetic prognostic factors cannot be replaced by the expression markers.

Approved and emerging PI3K inhibitors for the treatment of chronic lymphocytic leukemia and non-Hodgkin lymphoma.

INTRODUCTION: PI3K inhibition with idelalisib (at that time CAL-101) was at the forefront of the development of molecularly targeted therapies in Chronic Lymphocytic Leukemia (CLL)/Small Lymphocytic Leukemia (SLL) and follicular lymphoma. However, after initial approval, subsequent trials identified specific immune-mediated and infectious toxicity that led to a reduced use and stopped the further development of this agent. PI3K inhibition as a treatment paradigm fell out of favor compared to other developments such as BTK or BCL2 inhibitors. AREAS COVERED: This review provides an overview of the experience with approved PI3Ki, including long-term experience, and highlights the current PI3Ki developments in CLL, B-cell and T-Cell Non-Hodgkin's Lymphoma. EXPERT OPINION: With careful monitoring and prophylaxis usage of the first-generation PI3K inhibitor, idelalisib, in the approved indications, it is safe and remains an option in higher line therapy after the failure of other novel agents and/or chemoimmunotherapy. New developments with next-generation PI3K inhibitors of improved tolerability and sustained efficacy reignited the treatment principle and already led to newly approved therapeutic options for patients. Certainly, the authors here believe that PI3K inhibitors as a monotherapy and in combination with other agents is currently a rapidly evolving field in cancer treatment.

Cetuximab monotherapy and cetuximab plus capecitabine as first-line treatment in older patients with RAS- and BRAF wild-type metastatic colorectal cancer. Results of the multicenter phase II trial SAKK 41/10.

INTRODUCTION: While the anti-VEGF antibody bevacizumab was studied repeatedly as part of low-intensity regimens in less fit elderly patients with metastatic colorectal cancer (mCRC), anti-EGFR antibodies as upfront treatment modality have been scarcely investigated. MATERIAL AND METHODS: In SAKK 41/10, the benefit of cetuximab, either alone or in combination with capecitabine, was evaluated in vulnerable elderly patients with RAS/BRAF-wild-type mCRC. RESULTS AND DISCUSSION: The trial was stopped prematurely due to slow accrual after the inclusion of 24 patients (11 in the monotherapy arm, 13 in the combination arm). Median patient age was 80 years (range 71-89), median CIRS-G score 7 (range 2-13), and median IADL score 7 (range 3-8). At week 12, 6 of 11 patients (55%) were progression-free in the cetuximab monotherapy arm and 9 of 13 patients (69%) in the combination arm. Response rate was 9% in the monotherapy arm and 38% combination arm. The 6 patients with right-sided primary tumors were not responsive to cetuximab. NGS revealed additional mutations affecting the RAS/RAF/MAP kinase pathway in 5 patients; 4 of these patients showed early disease progression. Cetuximab was generally well tolerated and a trend toward an improvement of symptom-related QoL was observed. In the combination arm, a higher incidence of toxicities and treatment stoppings was observed. In conclusion, trial recruitment - requiring both geriatric as well as molecular eligibility criteria - proved more difficult than expected. Bearing in mind the very small sample size, upfront cetuximab treatment appeared tolerable and showed promising activity in left-sided tumors in both treatment arms.

Delineation of distinct tumour profiles in mantle cell lymphoma by detailed cytogenetic, interphase genetic and morphological analysis.

Mantle cell lymphoma (MCL) is an aggressive lymphoid tumour characterized by the translocation t(11;14)(q13;q32) and a poor clinical outcome (median survival: 3-4 years). Recent studies revealed that increased proliferation of the tumour cells and certain chromosomal aberrations, such as deletions of 17p13 and 9p21 represent major adverse biological markers in this disease, although the molecular targets of chromosomal imbalances in MCL have not been identified for the large majority of loci affected. To correlate histomorphological and proliferation features of MCL with genetic findings, we investigated 223 MCL by fluorescence in situ hybridization (FISH) (n = 157) and/or classical cytogenetic banding analysis (n = 129). FISH analysis turned out to be distinctly more sensitive in the delineation of aberrations. Complex karyotypic alterations were associated with higher proliferation indices and inferior prognosis. A comprehensive analysis of biological features including genetic alterations in MCL by hierarchical clustering resulted in the delineation of four tumour subgroups differing with respect to their genetic constitution and suggesting different transformation or progression pathways. Moreover, in one of the groups identified, a more indolent clinical behaviour was associated with few secondary aberrations and fewer known high-risk chromosomal aberrations, which points to the importance of the quality of karyotypic evolution in MCL tumours.

Genomic aberrations in mantle cell lymphoma detected by interphase fluorescence in situ hybridization. Incidence and clinicopathological correlations.

BACKGROUND: The genetic hallmark of mantle cell lymphoma is a t(11;14)(q13;q32). However, additional genomic alterations are likely involved in the pathogenesis of this lymphoma. DESIGN AND METHODS: To determine the incidence and clinical relevance of these aberrations, we analyzed 103 well-characterized samples of mantle cell lymphoma by fluorescence in situ hybridization for the most common recurrent additional genomic findings. RESULTS: Screening 16 different regions we detected additional genomic aberrations in 92% of the cases of mantle cell lymphoma. Common gains included 3q26, 8q24, 15q23, 7p15, and common losses 13q14, 11q22-q23, 9p21, 1p22, 17p13, 6q27, and 8p22. Deletions 8p22, 9p21, 13q14, and gain of 7p15 were associated with evidence of clonal heterogeneity. While there was no correlation of additional genomic aberrations and VH-mutation status, gain of 15q23 and deletion 6q27 were associated with lower disease stage (p=0.01 and p=0.04, respectively). Patients with deletion 13q14 had shorter overall survival times (p=0.01), and there was a strong trend towards inferior outcome in patients with deletion 9p21 (p=0.07). In multivariable analysis, loss of 13q14 and an International Prognosis Index score >/= 3 turned out to be significantly associated with inferior clinical outcome (p=0.002 and p<0.001, respectively). CONCLUSIONS: The comprehensive analysis of additional genomic aberrations in mantle cell lymphoma provided further evidence for the prognostic relevance of loss of 13q14, which warrants evaluation within prospective trials. Furthermore, our analysis gave novel insights into the pathogenesis of mantle cell lymphoma with regard to the detection of clonal heterogeneity, possibly indicating clonal evolution in this type of lymphoma.

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.

Chronic Lymphocytic Leukemia with Mutated IGHV4-34 Receptors: Shared and Distinct Immunogenetic Features and Clinical Outcomes.

Purpose: We sought to investigate whether B cell receptor immunoglobulin (BcR IG) stereotypy is associated with particular clinicobiological features among chronic lymphocytic leukemia (CLL) patients expressing mutated BcR IG (M-CLL) encoded by the IGHV4-34 gene, and also ascertain whether these associations could refine prognostication.Experimental Design: In a series of 19,907 CLL cases with available immunogenetic information, we identified 339 IGHV4-34-expressing cases assigned to one of the four largest stereotyped M-CLL subsets, namely subsets #4, #16, #29 and #201, and investigated in detail their clinicobiological characteristics and disease outcomes.Results: We identified shared and subset-specific patterns of somatic hypermutation (SHM) among patients assigned to these subsets. The greatest similarity was observed between subsets #4 and #16, both including IgG-switched cases (IgG-CLL). In contrast, the least similarity was detected between subsets #16 and #201, the latter concerning IgM/D-expressing CLL. Significant differences between subsets also involved disease stage at diagnosis and the presence of specific genomic aberrations. IgG subsets #4 and #16 emerged as particularly indolent with a significantly (P < 0.05) longer time-to-first-treatment (TTFT; median TTFT: not yet reached) compared with the IgM/D subsets #29 and #201 (median TTFT: 11 and 12 years, respectively).Conclusions: Our findings support the notion that BcR IG stereotypy further refines prognostication in CLL, superseding the immunogenetic distinction based solely on SHM load. In addition, the observed distinct genetic aberration landscapes and clinical heterogeneity suggest that not all M-CLL cases are equal, prompting further research into the underlying biological background with the ultimate aim of tailored patient management. Clin Cancer Res; 23(17); 5292-301. ©2017 AACR.

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.

Hidden gene amplifications in aggressive B-cell non-Hodgkin lymphomas detected by microarray-based comparative genomic hybridization.

DNA amplifications are important mechanisms for proto-oncogene activation. Comparative genomic hybridization (CGH) to metaphase chromosome preparations has revealed amplifications in 10-20% of B-cell lymphomas (B-NHL). We analysed a series of 16 aggressive non-Hodgkin lymphomas by the new approach termed Matrix-CGH (M-CGH) using genomic DNA microarrays as hybridization target. For M-CGH, a dedicated B-cell lymphoma chip was constructed containing 496 genomic targets covering oncogenes, tumor suppressor genes as well as chromosome regions frequently altered in B-NHL. In 10 of 16 samples a total of 15 DNA amplifications were identified. The amplicons included BCL2, REL, CCND1, CCND2, JAK2, FGF4 and MDM2. Four of the 15 amplifications remained undetected by chromosomal CGH. The respective amplicons mapped to bands 2p13, 9p13-p21 and 12q24 and, were confirmed by fluorescence in situ hybridization. Furthermore, for four genomically amplified genes real-time quantitative reverse transcription polymerase chain reaction revealed elevated mRNA expression levels. These data show the superior diagnostic sensitivity of the newly developed diagnostic tool. As only a small portion of the genome (approximately 1.5%) has been analysed by the present DNA array, it is likely that gene amplifications are much more common in aggressive lymphomas than previously assumed.

BRAF mutations in chronic lymphocytic leukemia.

BRAF mutations have been shown to occur at a high frequency in melanoma and thyroid cancer, but also at lower frequencies in hematological malignancies. To assess the potential role of BRAF, we have sequenced exons 11 and 15 of BRAF in 138 cases with chronic lymphocytic leukemia (CLL) and 32 cases of B-cell prolymphocytic leukemia (B-PLL). We found an incidence of BRAF mutations of 2.8% in CLL (4/138), while no cases with B-PLL showed BRAF mutations. The analysis of a cohort of patients with fludarabine-refractory disease (n = 87) showed no increase in the mutation incidence, suggesting that this mutation is not selected for during the disease progression. A limited analysis of the effect of BRAF inhibition in primary CLL cells showed no cell death induction in CLL samples with and without BRAF mutations. Our analysis suggests that BRAF mutations occur at a low frequency in CLL. The pharmacological inhibition of MEK/ERK signaling using the mutant BRAF inhibitor PLX4720 showed no effect on viability in vitro in CLL cases.

Hypereosinophilia driven by GM-CSF in large-cell carcinoma of the lung.

In contrast to leukocytosis, paraneoplastic hypereosinophilia is uncommon in lung cancer. We present a patient with large-cell carcinoma of the lung, in which cancer cells generate large amounts of GM-CSF leading to a leukemoid reaction with prominent hypereosinophilia and potentially involved in autocrine tumor stimulation.

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.

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.

Quantitative gene expression deregulation in mantle-cell lymphoma: correlation with clinical and biologic factors.

PURPOSE: There is evidence for a direct role of quantitative gene expression deregulation in mantle-cell lymphoma (MCL) pathogenesis. Our aim was to investigate gene expression associations with other pathogenic factors and the significance of gene expression in a multivariate survival analysis. PATIENTS AND METHODS: Quantitative expression of 20 genes of potential relevance for MCL prognosis and pathogenesis were analyzed using real-time reverse transcriptase polymerase chain reaction and correlated with clinical and genetic factors, tumor morphology, and Ki-67 index in 65 MCL samples. RESULTS: Genomic losses at the loci of TP53, RB1, and P16 were associated with reduced transcript levels of the respective genes, indicating a gene-dosage effect as the pathomechanism. Analysis of gene expression correlations between the candidate genes revealed a separation into two clusters, one dominated by proliferation activators, another by proliferation inhibitors and regulators of apoptosis. Whereas only weak associations were identified between gene expression and clinical parameters or blastoid morphology, several genes were correlated closely with the Ki-67 index, including the short CCND1 variant (positive correlation) and RB1, ATM, P27, and BMI (negative correlation). In multivariate survival analysis, expression levels of MYC, MDM2, EZH2, and CCND1 were the strongest prognostic factors independently of tumor proliferation and clinical factors. CONCLUSION: These results indicate a pathogenic contribution of several gene transcript levels to the biology and clinical course of MCL. Genes can be differentiated into factors contributing to proliferation deregulation, either by enhancement or loss of inhibition, and proliferation-independent factors potentially contributing to MCL pathogenesis by apoptosis impairment.

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.