Real-time RT-PCR assay for quantifying cyclin D1 mRNA in B-cell non-Hodgkin's lymphomas

Swertia chirayita suppresses the growth of non-small cell lung cancer A549 cells and concomitantly induces apoptosis via downregulation of JAK1/STAT3 pathway

Lung carcinoma is the leading cause of cancer-related mortalities worldwide, and present therapeutical interventions are not successful enough to treat this disease in many cases. Recent years have witnessed a surge in exploring natural compounds for their antiproliferative efficacy to expedite the characterization of novel anticancer chemotherapeutics. Swertia chirayita is a valued medicinal herb and possess intrinsic pharmaceutical potential. However, elucidation of its anticancer effects at molecular levels remains unclear and needs to be investigated. We assessed the anticancer and apoptotic efficacy of S. chirayita ethanolic extract (Sw-EtOH) on non-small cell lung cancer (NSCLC) A549 cells during this exploratory study. The results elucidated that S. chirayita extract induced toxic effects within lung cancer cells by ~1 fold during cytotoxicity and LDH release assay at a 400 μg/ml concentration. Sw-EtOH extract elevates the level of ROS, resulting in the disruption of Δψm and release of cytosolic cytochrome c by 3.15 fold. Activation of caspases-3, -8 & -9 also escalated by ~1 fold, which further catalyze the augmentation of PARP cleavage (~3 folds), resulting in a four-fold increase in Sw-EtOH induced apoptosis. The gene expression analysis further demonstrated that Sw-EtOH extracts inhibited JAK1/STAT3 signaling pathway by down-regulating the levels of JAK1 and STAT3 to nearly half a fold. Treatment of Sw-EtOH modulates the expression level of various STAT3 associated proteins, including Bcl-XL, Bcl-2, Mcl-1, Bax, p53, Fas, Fas-L, cyclinD1, c-myc, IL-6, p21 and p27 in NSCLC cells. Thus, our study provided a strong impetus that Sw-EtOH holds the translational potential of being further evaluated as efficient cancer therapeutics and a preventive agent for the management of NSCLC.

Cyclin D1 mRNA as a molecular marker for minimal residual disease monitoring in patients with mantle cell lymphoma

Chromosomal translocation t(11;14)(q13;q32) is a characteristic molecular marker of mantle cell lymphoma (MCL) and leads to the fusion of the immunoglobulin heavy chain enhancer-promoter with the cyclin D1 gene. Both aberrant cyclin D1 expression and underlying chromosomal aberration may be used as molecular targets for monitoring minimal residual disease (MRD). The present study aims to assess the usefulness of quantitative cyclin D1 gene expression compared to the standardised but more technologically demanding DNA-based method for immunoglobulin heavy chain (IGH) or t(11;14) clone-specific gene rearrangement quantification in a cohort of bone marrow (BM) and peripheral blood (PB) samples from patients with MCL. We simultaneously evaluated DNA-MRD and cyclin D1 expression levels in 234 samples from 57 patients. We observed that both in DNA-MRD positive and negative BM/PB pairs from the same time points the expression levels of cyclin D1 are lower in PB than in BM (median 19×, BM/PB range 0.41-352). The correlation of cyclin D1 transcript levels with DNA-MRD or with flow cytometry was good only in samples with a very high infiltration. In DNA-MRD-negative BM samples, we observed a significant heterogeneity of cyclin D1 expression (in the range of more than three orders of magnitude). This is in contrast to previous reports demonstrating the usefulness of cyclin D1 for MRD monitoring that did not use DNA-based method as a reference. In PB, the specificity of cyclin D1 expression was better due to a lower physiological background. In conclusion, we show that cyclin D1 is unsuitable for MRD monitoring in BM.

Role of MYC in B Cell Lymphomagenesis

B cell lymphomas mainly arise from different developmental stages of B cells in germinal centers of secondary lymphoid tissue. There are a number of signaling pathways that affect the initiation and development of B cell lymphomagenesis. The functions of several key proteins that represent branching points of signaling networks are changed because of their aberrant expression, degradation, and/or accumulation, and those events determine the fate of the affected B cells. One of the most influential transcription factors, commonly associated with unfavorable prognosis for patients with B cell lymphoma, is nuclear phosphoprotein MYC. During B cell lymphomagenesis, oncogenic MYC variant is deregulated through various mechanisms, such as gene translocation, gene amplification, and epigenetic deregulation of its expression. Owing to alterations of downstream signaling cascades, MYC-overexpressing neoplastic B cells proliferate rapidly, avoid apoptosis, and become unresponsive to most conventional treatments. This review will summarize the roles of MYC in B cell development and oncogenesis, as well as its significance for current B cell lymphoma classification. We compared communication networks within transformed B cells in different lymphomas affected by overexpressed MYC and conducted a meta-analysis concerning the association of MYC with tumor prognosis in different patient populations.

Consensus reference gene(s) for gene expression studies in human cancers: end of the tunnel visible?

BACKGROUND

Gene expression studies are increasingly used to provide valuable information on the diagnosis and prognosis of human cancers. Also, for in vitro and in vivo experimental cancer models gene expression studies are widely used. The complex algorithms of differential gene expression analyses require normalization of data against a reference or normalizer gene, or a set of such genes. For this purpose, mostly invariant housekeeping genes are used. Unfortunately, however, there are no consensus (housekeeping) genes that serve as reference or normalizer for different human cancers. In fact, scientists have employed a wide range of reference genes across different types of cancer for normalization of gene expression data. As a consequence, comparisons of these data and/or data harmonizations are difficult to perform and challenging. In addition, an inadequate choice for a reference gene may obscure genuine changes and/or result in erroneous gene expression data comparisons.

METHODS

In our effort to highlight the importance of selecting the most appropriate reference gene(s), we have screened the literature for gene expression studies published since the turn of the century on thirteen of the most prevalent human cancers worldwide.

CONCLUSIONS

Based on the analysis of the data at hand, we firstly recommend that in each study the suitability of candidate reference gene(s) should carefully be evaluated in order to yield reliable differential gene expression data. Secondly, we recommend that a combination of PPIA and either GAPDH, ACTB, HPRT and TBP, or appropriate combinations of two or three of these genes, should be employed in future studies, to ensure that results from different studies on different human cancers can be harmonized. This approach will ultimately increase the depth of our understanding of gene expression signatures across human cancers.

Cellular intrinsic factors involved in the resistance of squamous cell carcinoma to photodynamic therapy

Photodynamic therapy (PDT) is widely used to treat non-melanoma skin cancer. However, some patients affected with squamous cell carcinoma (SCC) do not respond adequately to PDT with methyl-δ-aminolevulinic acid (MAL-PDT) and the tumors acquire an infiltrative phenotype and became histologically more aggressive, less differentiated, and more fibroblastic. To search for potential factors implicated in SCC resistance to PDT, we have used the SCC-13 cell line (parental) and resistant SCC-13 cells obtained by repeated MAL-PDT treatments (5th and 10th PDT-resistant generations). Xenografts assays in immunodeficient mice showed that the tumors generated by resistant cells were bigger than those induced by parental cells. Comparative genomic hybridization array (aCGH) showed that the three cell types presented amplicons in 3p12.1 CADM2, 7p11.2 EFGR, and 11q13.3 CCND1 genes. The 5th and 10th PDT-resistant cells showed an amplicon in 5q11.2 MAP3K1, which was not present in parental cells. The changes detected by aCGH on CCND1, EFGR, and MAP3K1 were confirmed in extracts of SCC-13 cells by reverse-transcriptase PCR and by western blot, and by immunohistochemistry in human biopsies from persistent tumors after MAL-PDT. Our data suggest that genomic imbalances related to CCND1, EFGR, and particularly MAP3K1 seem to be involved in the development of the resistance of SCC to PDT.

Molecular detection of t(11;14)(q13;q32) in mantle cell lymphoma

Mantle cell lymphoma (MCL) is characterized by the presence of t(11;14)(q13;q32) which juxtaposes CCND-1 gene (also known as BCL-1, PRAD-1) at 11q13 with an enhancer of the IGH@ gene at 14q32. The resultant overexpression of cyclin D1 plays an essential role in the pathogenesis of MCL. The breakpoints on chromosome 14 occur 5' to one of six JH segments, whereas only 30-50% of the breakpoints on chromosome 11 are localized within a 1 kb region called the major translocation cluster (MTC) which can be easily assessed by polymerase chain reaction (PCR). The remainder of the breakpoints are widely scattered over approximately 120 kb, making PCR analysis infeasible. We describe a TaqMan-based real-time PCR assay to detect and quantify IGH@/BCL1 fusion products in newly diagnosed MCL, and to monitor minimal residual disease during treatment or early relapse in MTC-positive cases.

Cyclin D1 (CCND1) messenger RNA expression as assessed by real-time PCR contributes to diagnosis and follow-up control in patients with mantle cell lymphoma

Molecular diagnosis of mantle cell lymphoma (MCL) can be difficult because the t(11;14)/IGH@-CCND1 is extremely heterogeneous at the DNA level. Aiming to establish a reliable molecular tool that could be easily implemented in routine diagnostics, we developed a new real-time polymerase chain reaction (PCR) assay for CCND1 expression measurement and evaluated 451 cases: 142 MCL, 76 chronic lymphocytic leukemia, 20 hairy cell leukemia, 13 hairy cell leukemia-variant, 20 splenic marginal zone lymphoma, 91 other mature B-cell neoplasms, 29 other hematologic neoplasms, and 60 healthy individuals. Sensitivity of the real-time PCR assay was up to 10(-4). In t(11;14)/IGH@-CCND1 positive lymphoma samples (n = 150), median %CCND1/ABL1 expression level was 178.2 (range: 1.5-4, 152.0). Normalized by t(11;14)/IGH@-CCND1 positive cells as determined by fluorescence in situ hybridization IGH@-CCND1 positive samples showed a median %CCND1/ABL1 of 445.8 (range: 17.9-4,848.5). A normalized %CCND1/ABL1 expression of at least 17.0 was chosen as threshold for CCND1 positivity. For unnormalized samples, the positive detection rate of t(11;14)/IGH@-CCND1 by CCND1 expression was 87.3%. Healthy individuals had low %CCND1/ABL1 (median, 1.1; range, 0.0-7.8). The negative predictive value for exclusion of a t(11;14)/IGH@-CCND1 by CCND1 expression was 95.3% by the above threshold. %CCND1/ABL1 was higher in MCL than in the remaining B-cell lymphomas (mean ± SD, 392.9 ± 685.3 vs. 46.0 ± 305.0; p < 0.001). In 66 follow-up samples, CCND1 showed 2.5-3.5 log reduction after chemotherapy and increase at relapse. CCND1 expression could serve as adjunct to other techniques in diagnosis and follow-up of B-cell lymphomas.

Toll-like receptor-9 agonists increase cyclin D1 expression partly through activation of activator protein-1 in human oral squamous cell carcinoma cells

Increasing evidence suggests that malignant transformation can result from chronic infection, and Toll-like receptors (TLRs) may play an important role in this process. We have previously reported that the increased expression of TLR-9 is associated with tumor cell proliferation in oral cancer. However, the mechanisms involved have not been elucidated. The aim of this study was to investigate whether CpG-oligodeoxynucleotides (CpG-ODN), a special TLR-9 agonist, is able to exert the proliferation-promoting effect in human oral squamous cell carcinoma (OSCC), and to explore the possible underlying molecular mechanism. Flow cytometry, MTT, and colony formation assay were used to evaluate cell proliferation and cell cycle distribution. The mRNA and protein levels were analyzed by quantitative RT-PCR and Western blot assay. Luciferase reporter gene, EMSA, and ChIP assays were used to detect the activity of activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) in HB cells. Results showed that CpG-ODN could stimulate proliferation of HB cells in a dose- and time-dependent manner with a promoted G(1) /S cell cycle progression. Increased cyclin D1 expression was detected in the nuclear region after CpG-ODN treatment. Moreover, CpG-ODN promoted nuclear translocation and activation of AP-1, which appeared to be required for TLR-9-mediated cyclin D1 expression and subsequently cell proliferation, but seemed to have little impact on NF-κB activity. Our results indicate that CpG-ODN stimulates tumor cell proliferation through TLR-9-mediated AP-1-activated cyclin D1 expression in OSCC HB cells. Pharmacologic inhibition of the TLR-9/AP-1/cyclin D1 pathway may be a new therapeutic approach for prevention as well as treatment of OSCC.

Monitoring bortezomib therapy in multiple myeloma: screening of cyclin D1, D2, and D3 via reliable real-time polymerase chain reaction and association with clinico-pathological features and outcome

Cyclins D1, D2, and D3 (CCND1, 2, 3) are regulated by proteasomal degradation. Their overexpression in multiple myeloma (MM) has prognostic value. We performed this pilot study to analyze a possible association between CCND1-3 overexpression and response to treatment with the proteasome inhibitor bortezomib, since a specific prognostic marker for bortezomib response has not been reported, but would be ideal to predict who benefits most from bortezomib in times of several potentially efficient therapeutic options. Bone marrow (BM) specimens of 20/47 consecutive patients were available for reliable CCND1-3 analyses by real-time PCR. With CCND1 overexpression in 9/20 patients, the risk for progression after bortezomib treatment was significantly decreased (HR 0.102, 95% CI 0.021-0.498, p = 0.0048) and progression-free survival substantially prolonged (p = 0.0011). Our study is the first to suggest that overexpressed CCND1 in MM is an independent prognostic marker associated with a more durable response to bortezomib. These preliminary results warrant a larger study.

The basis and rational use of molecular genetic testing in mature B-cell lymphomas

An increasing number of neoplasms are associated with variably specific genetic abnormalities. This is best exemplified by hematological malignancies, in which there is a growing list of entities that are defined by their genetic lesion(s); this is not (yet) the case in mature B-cell lymphomas. However, enhanced insights into the pathogenesis of this large and diverse group of lymphomas have emerged with the ongoing unraveling of a plethora of fascinating genetic abnormalities. The purpose of this review is to synthesize well-recognized data and nascent discoveries in our understanding of the genetic basis of a spectrum of mature B-cell lymphomas, and how this may be applied to contemporary clinical practice. Despite the explosion of new and exciting knowledge in this arena, with the potential for enhanced diagnostic and prognostic strategies, it is essential to remain cognizant of the limitations (and complexity) of genetic investigations, so that assays can be developed and used both judiciously and rationally.

Cyclin D1 expression in B-cell lymphomas

OBJECTIVE

Cyclin D1, an important component of cell cycle machinery and a protein with known oncogenic potential, is downregulated in normal mature B lymphocytes. Its expression detected in a number of malignancies, including B-cell lymphomas, may be important for oncogenesis.

MATERIALS AND METHODS

In our work, we determined the level of cyclin D1 expression in various B-cell lymphomas (i.e., mantle cell lymphoma, B-cell chronic lymphocytic leukemia, diffuse large B-cell lymphoma, follicular lymphoma, and marginal zone lymphoma) and compared it with normal B cells. For cyclin D1 level evaluation, the real-time quantitative polymerase chain reaction data was normalized. We tested five reference genes for stability on our sample set and using the three most stable ones (YWHAZ, ubiquitin c, and HPRT) obtained rather small intra-group variance for cyclin D1 expression in most lymphomas. This allowed their statistically significant ranking according to cyclin D1 expression level.

RESULTS

Median values of normalized cyclin D1 expression determined by real-time quantitative polymerase chain reaction were 1.32 for mantle cell lymphoma, 0.02 for B-cell chronic lymphocytic leukemia, 0.009 for diffuse large B-cell lymphoma, 0.004 for marginal zone lymphoma, 0.002 for follicular lymphoma compared with 0.0003 for reactive lymphoid tissue, and 0.00004 for sorted B cells of healthy donors.

CONCLUSIONS

Our data demonstrate that mantle cell lymphoma, a lymphoma with t(11;14)(q13;q32) translocation, has the level of cyclin D1 increased by four orders of magnitude, while other B-cell lymphomas without t(11;14)(q13;q32) translocation still have the level of cyclin D1 significantly elevated above that of normal lymphocytes (2 orders for B-cell chronic lymphocytic leukemia and an order for other lymphomas) and suggests more than one method of its upregulation in malignant B cells.

Expression of matrix metalloproteinases 2 and 9 in human gastric cancer and superficial gastritis

AIM: To assess expression of matrix metalloproteinases 2 (MMP2) and MMP9 in gastric cancer, superficial gastritis and normal mucosa, and to measure metalloproteinase activity.

METHODS: MMP2 and MMP9 mRNA expression was determined by quantitative real-time polymerase chain reaction. Normalization was carried out using three different factors. Proteins were analyzed by quantitative gelatin zymography (qGZ).

RESULTS: 18S ribosomal RNA (18SRNA) was very highly expressed, while hypoxanthine ribosyltransferase-1 (HPRT-1) was moderately expressed. MMP2 was highly expressed, while MMP9 was not detected or lowly expressed in normal tissues, moderately or highly expressed in gastritis and highly expressed in cancer. Relative expression of 18SRNA and HPRT-1 showed no significant differences. Significant differences in MMP2 and MMP9 were found between cancer and normal tissue, but not between gastritis and normal tissue. Absolute quantification of MMP9 echoed this pattern, but differential expression of MMP2 proved conflictive. Analysis by qGZ indicated significant differences between cancer and normal tissue in MMP-2, total MMP-9, 250 and 110 kDa bands.

CONCLUSION: MMP9 expression is enhanced in gastric cancer compared to normal mucosa; interpretation of differential expression of MMP2 is difficult to establish.

Wnt signaling stimulates transcriptional outcome of the Hedgehog pathway by stabilizing GLI1 mRNA

Wnt and Hedgehog signaling pathways play central roles in embryogenesis, stem cell maintenance, and tumorigenesis. However, the mechanisms by which these two pathways interact are not well understood. Here, we identified a novel mechanism by which Wnt signaling pathway stimulates the transcriptional output of Hedgehog signaling. Wnt/beta-catenin signaling induces expression of an RNA-binding protein, CRD-BP, which in turn binds and stabilizes GLI1 mRNA, causing an elevation of GLI1 expression and transcriptional activity. The newly described mode of regulation of GLI1 seems to be important to several functions of Wnt, including survival and proliferation of colorectal cancer cells.

Abnormal AP-1 protein expression in primary cutaneous B-cell lymphomas

BACKGROUND

Primary cutaneous B-cell lymphoma (PCBCL) consists mainly of primary cutaneous marginal zone B-cell lymphoma (PCMZL), primary cutaneous follicle centre lymphoma (PCFCL) and primary cutaneous large B-cell lymphoma, leg type (PCLBCL-LT). The activator protein 1 (AP-1) transcription factor includes JUN, FOS and other family members.

OBJECTIVES

To assess the expression pattern of AP-1 transcription factors in PCBCL.

METHODS

We analysed paraffin tissue sections from nine cases of PCMZL, seven PCFCL, six PCLBCL-LT and two unspecified PCBCL cases by using immunohistochemistry with antibodies against c-JUN, JUNB, JUND, c-FOS, RAF1, alphaPAK, CD30 and CCND1.

RESULTS

A positive staining for JUND (++) was observed in six cases of PCFCL (86%), five PCLBCL-LT (83%) and five PCMZL (56%). Positive CCND1 protein expression was present in four cases of PCLBCL-LT (67%), four PCFCL (57%) and four PCMZL (44%), and the two unspecified PCBCL cases. Expression of alphaPAK protein was seen in three cases of PCLBCL-LT (50%), two PCMZL (22%) and one PCFCL. However, c-JUN, c-FOS and RAF1 protein were rarely expressed in the PCBCL cases analysed; JUNB and CD30 protein expression was absent in these cases.

CONCLUSIONS

These findings suggest that the presence of abnormal AP-1 protein expression is associated with upregulation of JUND, CCND1 and alphaPAK and downregulation of JUNB in PCBCL.

Expanding therapeutic options in mantle cell lymphoma

Mantle cell lymphoma (MCL) still carries a poor prognosis. Chemoimmunotherapy (combination with rituximab) is the routine first-line therapy, although data strongly suggest a benefit from intensification through high-dose therapy with stem cell transplantation consolidation or dose-intense chemotherapy with HyperCVAD (fractionated cyclophosphamide/vincristine/doxorubicin/dexamethasone)/rituximab. Unfortunately, most patients still experience relapse, and a multitude of novel agents are currently being tested in this setting, including proteasome inhibitors with bortezomib (the first of its class and first Food and Drug Administration-approved drug in MCL), mammalian target of rapamycin inhibitors, Bcl-2 inhibitors, and antiangiogenesis agents, among others. Because of the relative rarity of the disease-MCL represents 6% of non-Hodgkin lymphoma-an obvious effort is needed to enroll patients on clinical trials. Not surprisingly, as in other non-Hodgkin lymphomas, MCL appears more and more as a heterogeneous disease, which might impact future clinical trial design through pharmacogenomics and hopefully help us develop smaller "molecular" relevant trials.

Discovery of novel epigenetic markers in non-Hodgkin's lymphoma

Non-Hodgkin's lymphoma (NHL) is a group of malignancies with heterogeneous genetic and epigenetic alterations. Discovery of molecular markers that better define NHL should improve diagnosis, prognosis and understanding of the biology. We developed a CpG island DNA microarray for discovery of aberrant methylation targets in cancer, and now apply this method to examine NHL cell lines and primary tumors. This methylation profiling revealed differential patterns in six cell lines originating from different subtypes of NHL. We identified 30 hypermethylated genes in these cell lines and independently confirmed 10 of them. Methylation of 6 of these genes was then further examined in 75 primary NHL specimens composed of four subtypes representing different stages of maturation. Each gene (DLC-1, PCDHGB7, CYP27B1, EFNA5, CCND1 and RARbeta2) was frequently hypermethylated in these NHLs (87, 78, 61, 53, 40 and 38%, respectively), but not in benign follicular hyperplasia. Although some genes such as DLC-1 and PCDHGB7 were methylated in the vast majority of NHLs, others were differentially methylated in specific subtypes. The methylation of the candidate tumor suppressor gene DLC-1 was detected in a high proportion of primary tumor and plasma DNA samples by using quantitative methylation-specific PCR analysis. This promoter hypermethylation inversely correlated with DLC-1 gene expression in primary NHL samples. Thus, this CpG island microarray is a powerful discovery tool to identify novel methylated genes for further studies of their relevant molecular pathways in NHLs and identification of potential epigenetic biomarkers of disease.

Blastoid and common variants of mantle cell lymphoma exhibit distinct immunophenotypic and interphase FISH features

AIMS

The recognition of blastoid variant (BV) of mantle cell lymphoma (MCL) is based on morphological criteria. Our aim was to analyse 18 MCL cases including four BV-MCL for their clinicopathological features, proliferation index, cyclin D1 and CDK4 expression and interphase fluorescence in-situ hybridization (FISH) pattern.

METHODS AND RESULTS

BV-MCL versus common MCL was characterized by a shorter overall duration of response after first-line therapy (11 months versus 28 months) and shorter overall survival (20 months versus 42 months). Interphase FISH showed a t(11;14) fusion pattern in all MCL tested cases. However, the four blastoid cases were characterized by extra copies of CCND1 signals. Using additional probes of chromosomes 11, 18, 21, these signals were shown to be the result of hypotetraploidy and not of a specific amplification of the normal or the translocated CCND1 allele. Moreover, the BV-MCL cases were characterized by a combined high percentage of cells expressing cyclin D1 and/or CDK4 with a proliferation (MIB-1-Ki67) index above 50%. Such features allowed the recognition of areas of large cell transformation in the case of secondary BV-MCL.

CONCLUSIONS

Since distinction between BV and common MCL is of clinical relevance, our data underline the need to add phenotypic and cytogenetic criteria to cytomorphology for a better recognition of BV-MCL.

The role of molecular studies in lymphoma diagnosis: a review

Lymphoma classification is based on a multiparametric approach to diagnosis, in which clinical features, morphology, immunophenotype, karyotype and molecular characteristics are important to varying degrees. While in most cases, a diagnosis can be confidently established on the basis of morphology and immunophenotype alone, a small proportion of diagnostically difficult cases will rely on molecular studies to enable a definitive diagnosis. This review discusses the various molecular techniques available including Southern blotting (SB), polymerase chain reaction (PCR), fluorescence in situ hybridisation (FISH)--including multicolour-FISH/spectral karyotyping and comparative genomic hybridisation--and also gene expression profiling using cDNA microarray technology. Emphasis is given to the analysis of antigen receptor gene rearrangements and chromosomal translocations as they relate to lymphoma diagnosis and also in the setting of minimal residual disease (MRD) detection and monitoring. Laboratories performing these tests need to have expertise in these areas of testing, and there is a need for greater standardisation of molecular tests. It is important to know the sensitivity and specificity of each test as well as its limitations and the pitfalls in the interpretation of results. Above all, results of molecular testing should never be considered in isolation, and must always be interpreted in the context of clinical and other laboratory data.

Real-time quantitative reverse transcription-PCR for cyclin D1 mRNA in blood, marrow, and tissue specimens for diagnosis of mantle cell lymphoma

BACKGROUND

Overexpression of cyclin D1 mRNA, found in mantle cell lymphoma (MCL), is a critical diagnostic marker. We investigated the use of real-time reverse transcription-PCR (RT-PCR) for cyclin D1.

METHODS

We studied 97 fresh specimens (50 blood, 30 bone marrow, 15 lymph node, and 2 other samples) from patients diagnosed with a variety of lymphoproliferative diseases, including 25 cases of MCL. We used real-time quantitative RT-PCR to evaluate cyclin D1 mRNA expression. Because blood and marrow specimens may contain only a minority of potentially malignant cells (as opposed to most lymph nodes) and to increase sensitivity, we normalized the cyclin D1 mRNA concentrations to mRNA of a B-cell-specific marker, CD19, as well as to previously characterized beta(2)-microglobulin mRNA.

RESULTS

In 16 of 21 cases of MCL with overt disease, the ratio of cyclin D1 mRNA to beta(2)-microglobulin mRNA was increased, but all 21 cases showed increased ratios of cyclin D1 mRNA to CD19 mRNA. Cyclin D1 mRNA was low or undetectable in various lymphoproliferative diseases, including cases of ambiguous immunophenotype. The mRNA ratios were stable over 3-7 days of sample storage.

CONCLUSION

Quantitative RT-PCR for cyclin D1 mRNA normalized to CD19 mRNA can be used in the diagnosis of MCL in blood, marrow, and tissue.

Chromosomal translocations involved in non-Hodgkin lymphomas

CONTEXT

The discovery that recurrent chromosomal translocations are involved in the pathogenesis of non-Hodgkin lymphomas has greatly improved our understanding of these diseases and revolutionized their diagnosis.

OBJECTIVE

To review the mechanisms by which chromosomal translocations occur and contribute to the pathogenesis of various types of non-Hodgkin lymphomas and to review the utility of molecular genetic methods for the assessment of these translocations.

DATA SOURCES AND STUDY SELECTION

Primary research studies and reviews published in the English language that focus on chromosomal translocation and non-Hodgkin lymphomas.

DATA EXTRACTION AND SYNTHESIS

Chromosomal translocations, which usually result in oncogene activation, occur in many types of B- and T-cell lymphoma, and their detection is helpful for establishing an accurate diagnosis and monitoring disease following therapy. However, the precise mechanisms that explain how translocations occur remain unknown, although for some types of translocations a clear relationship has been established with immunoglobulin gene rearrangement mechanisms. In recent years, a number of genes deregulated by chromosomal translocations have been identified, and the detailed molecular mechanisms by which chromosomal translocations contribute to the pathogenesis of non-Hodgkin lymphoma are beginning to be elucidated.

CONCLUSIONS

Molecular genetic analysis has played a major role in improving our understanding of B- and T-cell non-Hodgkin lymphomas and has allowed more precise definition of lymphoma types. Molecular genetic tests to detect these translocations are important ancillary tools for the diagnosis and classification of malignant lymphomas.

Fluorescence in situ hybridization: method of choice for a definitive diagnosis of mantle cell lymphoma

Fluorescence in situ hybridization (FISH) using IGH/CCND1 probes was used to analyze 35 specimens including 27 paraffin sections, 3 bone marrow aspirates, and 5 peripheral blood smears. The 27 paraffin sections included 7 bone marrows, 10 lymph nodes, 3 spleens, 3 tonsils, 3 gastrointestinal biopsies, and 1 skin biopsy. Among these cases, 23 specimens were from 20 patients with mantle cell lymphoma (MCL) and 12 specimens were from 12 patients with non-MCL lymphomas/lymphoid hyperplasia. Specimens from all MCL patients showed positive results with FISH. In one patient, the archived paraffin sections were negative with FISH, but a fresh peripheral blood specimen showed a positive result. Negative results were obtained in all specimens from non-MCL cases. Flow cytometric analysis revealed that all cases of MCL showed CD19/CD5 staining, but the percentages of cells positive for CD23 and FMC-7 were variable, thus they cannot be depended upon for a definitive diagnosis of MCL. Immunohistochemical stains demonstrated positive staining for CD5 and CD20 and negative staining for CD23 in MCL cases but cyclin D1 was positive in only 10 of 13 MCL cases studied. Therefore, it appears that immunophenotyping alone is not sufficient to establish a definitive diagnosis of MCL. FISH should be routinely used when the diagnosis needs confirmation. FISH can be performed in a routine clinical laboratory, and it is applicable to archived material for retrospective studies. Other molecular cytogenetic techniques in comparison with FISH are discussed.

Detection of minimal residual disease in hematologic malignancies by real-time quantitative PCR: principles, approaches, and laboratory aspects

Detection of minimal residual disease (MRD) has prognostic value in many hematologic malignancies, including acute lymphoblastic leukemia, acute myeloid leukemia, chronic myeloid leukemia, non-Hodgkin's lymphoma, and multiple myeloma. Quantitative MRD data can be obtained with real-time quantitative PCR (RQ-PCR) analysis of immunoglobulin and T-cell receptor gene rearrangements, breakpoint fusion regions of chromosome aberrations, fusion-gene transcripts, aberrant genes, or aberrantly expressed genes, their application being dependent on the type of disease. RQ-PCR analysis can be performed with SYBR Green I, hydrolysis (TaqMan) probes, or hybridization (LightCycler) probes, as detection system in several RQ-PCR instruments. Dependent on the type of MRD-PCR target, different types of oligonucleotides can be used for specific detection, such as an allele-specific oligonucleotide (ASO) probe, an ASO forward primer, an ASO reverse primer, or germline probe and primers. To assess the quantity and quality of the RNA/DNA, one or more control genes must be included. Finally, the interpretation of RQ-PCR MRD data needs standardized criteria and reporting of MRD data needs international uniformity. Several European networks have now been established and common guidelines for data analysis and for reporting of MRD data are being developed. These networks also include standardization of technology as well as regular quality control rounds, both being essential for the introduction of RQ-PCR-based MRD detection in multicenter clinical treatment protocols.

Optimization of quantitative real-time RT-PCR parameters for the study of lymphoid malignancies

Real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) is a powerful method for measurement of gene expression for diagnostic and prognostic studies of non-Hodgkin's lymphomas (NHL). In order for this technique to gain wide applicability, it is critically important to establish a uniform method for normalization of RNA input. In this study, we have determined the best method to quantify the RNA/cDNA input per reaction and searched for the most useful endogenous control genes for normalization of the measurements, based on their abundance and lowest variability between different types of lymphoid cells. To accomplish these aims, we have analyzed the RNA expression of 11 potential endogenous control genes (glyceraldehyde-3-phosphate dehydrogenase, beta-actin, peptidylprolyl isomerase A, beta 2 microglobulin, protein kinase cGMP-dependent, type I, hypoxanthine phosphoribosyltransferase 1, TATA box binding protein, transferrin receptor, large ribosomal protein, beta-glucoronidase and 18S ribosomal RNA). In all, 12 different B- and T-cell lymphoma/leukemia cell lines, 80 B- and T-cell NHL specimens, and resting and activated normal B and T lymphocytes were screened. Normalization of the nucleic acid input by spectrophotometric OD(260) measurement of RNA proved more reliable than spectrophotometric or fluorometric measurements of cDNA or than electrophoretic estimation of the ribosomal and mRNA fractions. The protein kinase cGMP-dependent, type I (PRKG1) and the TBP genes were expressed at common abundance and exhibited the lowest variability among the cell specimens. We suggest that for further lymphoma studies based on the real-time RT-PCR quantification of gene expression, that RNA input in each reaction be equalized between the specimens by spectrophotometric OD(260) measurements. The expression of the gene of interest in different samples should be normalized by concomitant measurement of the PRKG1 and/or the TBP gene products.