bcl-1 rearrangement and cyclin D1 protein expression in mantle cell lymphoma

Combined epigenetic and immunotherapy for blastic and classical mantle cell lymphoma

Classical MCL (cMCL) constitutes 6-8% of all B cell NHL. Despite recent advances, MCL is incurable except with allogeneic stem cell transplant. Blastic mantle cell lymphoma (bMCL) is a rarer subtype of cMCL associated with an aggressive clinical course and poor treatment response, frequent relapse and poor outcomes. We treated 13 bMCL patients with combined epigenetic and immunotherapy treatment consisting of vorinostat, cladribine and rituximab (SCR). We report an increased OS greater than 40 months with several patients maintaining durable remissions without relapse for longer than 5 years. This is remarkably better then current treatment regimens which in bMCL range from 14.5-24 months with conventional chemotherapy regimens. We demonstrate that the G/A870 CCND1 polymorphism is predictive of blastic disease, nuclear localization of cyclinD1 and response to SCR therapy. The major resistance mechanisms to SCR therapy are loss of CD20 expression and evasion of treatment by sanctuary in the CNS. These data indicate that administration of epigenetic agents improves efficacy of anti-CD20 immunotherapies. This approach is promising in the treatment of MCL and potentially other previously treatment refractory cancers.

An unusual presentation of chronic lymphocytic leukemia/small lymphocytic lymphoma on mammography: Case report

Although rare, breast CLL/SLL should be considered in the differential diagnosis of a breast mass. A high index of suspicion is needed to differentiate this neoplasm from more common breast carcinomas like solid variant of invasive lobular carcinoma.

Cell Cycle Dysregulation in Mantle Cell Lymphoma: Genomics and Therapy

Cell cycle dysregulation caused by aberrant cyclin D1 and CDK4 expression is a major determinant for proliferation of cancer cells in mantle cell lymphoma (MCL). Inhibition of CDK4/6 induces G1 arrest of MCL cells in patients, appearing to deepen and prolong the clinical response to partner agents. This article reviews aberrations of cell cycle genes in MCL cells and clinical trials of CDK4/6 inhibitors for MCL. Integrative longitudinal functional genomics is discussed as a strategy to discover genomic drivers for resistance in cancer cells and cancer-immune interactions that potentially contribute to the clinical response to palbociclib combination therapy in MCL.

Targeting CDK4/6 in mantle cell lymphoma

Targeting the cell cycle represents a rational approach to mantle cell lymphoma (MCL) therapy, as aberrant expression of cyclin D1 and dysregulation of CDK4 underlie cell cycle progression and proliferation of MCL cells. Although cell cycle cancer therapy was historically ineffective due to a lack of selective and effective drugs, this landscape changed with the advent of selective and potent small-molecule oral CDK4/6 inhibitors. Here, we review the anti-tumor activities and clinical data of selective CDK4/6 inhibitors in MCL. We summarize the known mechanism of action of palbociclib, the most specific CDK4/6 inhibitor to date, and the strategy to leverage this specificity to reprogram MCL for a deeper and more durable clinical response to partner drugs. We also discuss integrative longitudinal functional genomics as a strategy to discover tumor-intrinsic genomic biomarkers and tumor-immune interactions that potentially contribute to the clinical response to palbociclib in combination therapy for MCL. Understanding the genomic basis for targeting CDK4/6 and the mechanisms of action and resistance in MCL may advance personalized therapy for MCL and shed light on drug resistance in other cancers.

Targeting Cyclin-Dependent Kinases in Synovial Sarcoma: Palbociclib as a Potential Treatment for Synovial Sarcoma Patients

Background

In synovial sarcomas alterations in the cyclin D1-CDK4/6-Rb axis have been described. Also, β-catenin, a cyclin D1 regulator, is often overexpressed. Additionally, studies have shown that the t(X;18) translocation influences tumor behavior partly through cyclin D1 activation. We investigated how alterations in the cyclin D1-CDK4/6-Rb axis impact prognosis and studied effects of targeting this axis with the CDK4/6 inhibitor palbociclib.

Methods

Synovial sarcoma samples (n = 43) were immunohistochemically stained for β-catenin, cyclin D1, p16, p21, p27, Rb, and phospho-Rb. Fluorescent in situ hybridization (FISH) was performed to detect CCND1 amplification or translocation. In 4 synovial sarcoma cell lines sensitivity to palbociclib was investigated using cell viability assays, and effects on the sensitive cell lines were evaluated on protein level and by cell cycle arrest.

Results

Expression of nuclear phospho-Rb and nuclear β-catenin in the patient samples was associated with poor survival. FISH showed a sporadic translocation of CCND1 in a subset of tumors. An 8-fold CCND1 amplification was found in 1 cell line, but not in the patient samples investigated. Palbociclib effectively inhibited Rb-phosphorylation in 3 cell lines, resulting in an induction of a G1 arrest and proliferation block.

Conclusions

In this series nuclear phospho-Rb and nuclear β-catenin expression were negative prognostic factors. In vitro data suggest that palbociclib may be a potential treatment for a subset of synovial sarcoma patients. Whether this effect can be enhanced by combination treatment deserves further preclinical investigations.

Electronic supplementary material

The online version of this article (doi:10.1245/s10434-016-5341-x) contains supplementary material, which is available to authorized users.

Large B-cell lymphoma of the base of the tongue and oral cavity: a practical approach to identifying prognostically important subtypes

OBJECTIVE

The aim of this study is to illustrate a practical approach to the identification of prognostically important subtypes of large B-cell lymphomas.

STUDY DESIGN

Twenty-six cases of large B-cell lymphoma in the base of the tongue and oral cavity were retrieved from 2003 through 2012. All cases were classified based on the 2008 World Health Organization criteria. Hematoxylin-eosin-stained sections, immunohistochemical stains, flow cytometric immunophenotypic data, and fluorescence in situ hybridization studies were performed and evaluated.

RESULTS

Four different subtypes of large B-cell lymphoma were identified: pleomorphic variant mantle cell lymphoma, Epstein-Barr virus-positive diffuse large B-cell lymphoma of the elderly, diffuse large B-cell lymphoma not otherwise specified, and B-cell lymphoma unclassifiable with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma, including a case of double-hit lymphoma.

CONCLUSIONS

Diverse subtypes of large B-cell lymphoma were identified in the base of tongue and oral cavity, and illustrate a practical approach to recognizing prognostically important lymphoma subtypes.

All trans retinoic acid nanodisks enhance retinoic acid receptor mediated apoptosis and cell cycle arrest in mantle cell lymphoma

Mantle cell lymphoma (MCL) is characterized by translocation t(11;14)(q13;q32), aggressive clinical behaviour, and poor patient outcomes following conventional chemotherapy. New treatment approaches are needed that target novel biological pathways. All trans retinoic acid (ATRA) is a key retinoid that acts through nuclear receptors that function as ligand-inducible transcription factors. The present study evaluated cell killing effects of ATRA-enriched nanoscale delivery particles, termed nanodisks (ND), on MCL cell lines. Results show that ATRA-ND induced cell death more effectively than naked ATRA (dimethyl sulphoxide) or empty ND. ATRA-ND induced reactive oxygen species (ROS) generation to a greater extent than naked ATRA. The antioxidant, N-acetylcysteine, inhibited ATRA-ND induced apoptosis. Compared to naked ATRA, ATRA-ND enhanced G1 growth arrest, up-regulated p21and p27, and down regulated cyclin D1. At ATRA concentrations that induced apoptosis, expression levels of retinoic acid receptor-alpha (RARalpha) and retinoid X receptor-gamma (RXRgamma) were increased. Compared to naked ATRA, ATRA-ND significantly stimulated transcriptional activity of RARA in a model carcinoma cell line. Furthermore, the RAR antagonist, Ro 41-5253, inhibited ATRA-ND induced ROS generation and prevented ATRA-ND induced cell growth arrest and apoptosis. In summary, incorporation of ATRA into ND enhanced the biological activity of this retinoid in cell culture models of MCL.

Expression of cyclin D2 is an independent predictor of the development of hepatic metastasis in colorectal cancer

INTRODUCTION

Cyclin D1 has been implicated in the progression of several cancers by virtue of its influence on progression of the G1/S phase of the cell cycle. However, little is known about the possible roles of cyclin D2 and D3 in colorectal cancers (CRCs).

METHOD

We investigated the expression levels of cyclin D2 and D3 in 84 CRC specimens. Antigen expression was determined by immunohistochemical analysis of cyclin D1, D2, D3, p16INK4A and Ki67 on tissue microarrays constructed using core samples from tumour centres and margins.

RESULTS

For the whole cohort, expression of cyclin D2 at the margin was associated with vascular invasion (P = 0.039), lymph node metastasis (P = 0.020) and liver metastasis (P < 0.001). In patients with stage I and II tumours (n = 84), elevated cyclin D2 and D3 were associated with vascular invasion (P = 0.014 and 0.028 respectively), liver metastasis (P = 0.001 and 0.007 respectively) and reduced disease specific survival (Cyclin D2, P < 0.022). No association was noted between the proliferative marker Ki-67 and the D-type cyclins.

CONCLUSION

These findings suggest that cyclin D2 expression at the invasive margin of CRCs is associated with liver metastasis and may serve as a useful prognostic marker and indicator of the need for adjuvant therapy.

Rituximab based therapy followed by autologous stem cell transplantation leads to superior outcome and high rates of PCR negativity in patients with indolent B-cell lymphoproliferative disorders

Autologous stem cell transplantation (ASCT) and rituximab based therapy represent effective treatments of indolent B-cell lymphoproliferative disorders (B-LPDs) that often induce molecular remission (MR). We assessed the impact of MR after treatment on prognosis of 57 patients with indolent B-LPDs. We also evaluated the impact of therapy on patients' outcome. Failure to achieve MR was identified as an independent risk factor regardless of treatment modality. PCR positive patients had shorter progression free survival (PFS) in contrast with patients in MR after rituximab (median 0.75 and 2.5 years respectively; p=0.006) or patients in MR after rituximab followed by ASCT (median 3.3 years; p=0.0032). PCR positive patients had a 5-year overall survival (OS) of only 40% compared to a 5-year OS of 76% for PCR negative patients after rituximab (p=0.0186) and 86% PCR negative patients after rituximab with ASCT (p=0.003). All nine patients transplanted with PCR positive graft relapsed (p=0.0023) with shorter PFS (p=0.0008). Rituximab based therapy induced MR in 25 (64%) compared to 18 (100%) patients after rituximab followed by ASCT (p=0.0025). We observed no difference in PFS between the transplant group (3.3 years) and rituximab based treatment (1.9 years), but the 5-year OS of patients with transplant was 85 and 59% respectively (p=0.0271). Patients with indolent B-LPDs who achieve MR have better prognosis. Rituximab based therapy induces MR in high number of patients, which can be further improved by ASCT and patients have an excellent outcome. PCR positive harvest represents a high risk of relapse after ASCT.

The Leukemic Presentation of Mantle-cell Lymphoma: Disease Features and Prognostic Factors in 58 Patients

Mantle-cell lymphoma (MCL) is a B-cell malignancy with distinct molecular genetics and pathological features. Peripheral blood involvement has been reported with variable frequency, but information on the natural history of cases presenting with leukemia is lacking. This study aimed to determine the clinical and prognostic features of such cases. We studied clinical features, tumor characteristics, prognostic factors and outcome in 58 patients with leukemic presentation of MCL. Diagnosis was based on morphology, immunophenotype, presence of t(11;14), histology and cyclin D1 expression. The median age was 62 years and male:female 2.4:1. Presenting features included splenomegaly (74%), lymphadenopathy (45%), hepatomegaly (17%) and, in a minority, gastro-intestinal involvement or involvement of Waldeyer's ring; 10% had lymphocytosis alone. Six patients developed central nervous system disease. Median lymphocyte count was 58 x 10(9)/l, 55% had anemia and 17% had thrombocytopenia. Morphology of peripheral blood showed small-cell MCL in 15% of cases, typical MCL in 46% and blastoid MCL in 39%. Immunological markers showed a typical phenotype (CD5+ CD23 -) in 68%, and atypical phenotypes, CD5- CD23- in 17% or CD5+ CD23+ in 15%. CLL scores were 0, 1 or 2 in 96%. Median overall survival was 36 months. Good response to first-line treatment (P = 0.0008) and splenomegaly (P = 0.03) were favorable prognostic factors, while other features including morphology and CD38 expression had no impact on survival or treatment response. This analysis demonstrates that except for splenomegaly, survival of MCL patients presenting with leukemia is not significantly influenced by clinical or tumor characteristics. Splenectomy is a useful treatment option in this group of patients.

Combined molecular diagnosis of B-cell lymphomas with t(11;14)(q13;q32) or t(14;18)(q32;q21) using multiplex- and long distance inverse-polymerase chain reaction

Translocations t(14;18)(q32;q21) and t(11;14)(q13;q32) are recurrent findings in follicular lymphoma (FL) and mantle cell lymphoma (MCL), respectively. However, the molecular counterparts of these translocations can only be detected in up to 75% of FL and 50% of MCL cases using routine techniques. To improve the efficiency of detection, we first devised a single-tube multiplex-polymerase chain reaction (PCR) assay with primers located within a conserved immunoglobulin heavy chain (IGH) sequence and 5' to the main breakpoint cluster regions of BCL2 and CCND1. Using this assay in 17 FL and 11 MCL diagnostic DNA samples, we readily identified a BCL2-IGH fusion in 65% of FL patients and a CCND1-IGH fusion in 55% of MCL patients. In the remaining cases, we used long distance inverse-PCR to detect BCL2-IGH and CCND1-IGH fusion genes with different BCL2 and CCND1 breakpoint locations. We found additional translocations in 3 patients (17%) with FL and in 4 patients (36%) with MCL. Taken together, we show that multiplex-PCR combined with long distance inverse-PCR detected a t(14;18) in 82% of FL patients and a t(11;14) in 91% of MCL patients, demonstrating that this 2-step protocol is an effective approach for molecular detection of t(11;14) and t(14;18) in B-cell lymphomas.

Cyclin D1 protein overexpression and CCND1 amplification in breast carcinomas: an immunohistochemical and chromogenic in situ hybridisation analysis

Conflicting results on the prevalence of cyclin D1 ovexpression and its correlation with CCND1 amplification and outcome of breast cancer patients have been reported. Owing to limited sensitivity and specificity of most antibodies against cyclin D1, evaluation of cyclin D1 immunoexpression is reported to be problematic. The aims of this study were to assess the prevalence of cyclin D1 expression in breast carcinomas using the SP4 rabbit monoclonal antibody; to correlate cyclin D1 expression with amplification, assessed using chromogenic in situ hybridisation (CISH); and to analyse the relationship between CCND1 amplification and overexpression with clinicopathological parameters and outcome in a tissue microarray containing replicate tumour samples from 245 breast cancer patients. Immunohistochemistry for cyclin D1 was performed using the SP4 and the results were scored according to the Allred scoring system. CISH was carried out using the Zymed CCND1 SpotLight probe. CISH signals were counted in 60 morphologically unequivocal neoplastic cells. Amplification was defined as >5 signals per nucleus in more than 50% of cancer cells, or when large gene copy clusters were seen. Strong cyclin D1 expression and CCND1 amplification were found in 67.4 and 14.5% of the cases, respectively. A strong correlation between cyclin D1 overexpression and CCND1 amplification was demonstrated (P<0.0001). Cyclin D1 expression showed a positive correlation with hormone receptor expression (both ER and PgR, P<0.0001). An inverse correlation was observed between an immunohistochemical panel of 'basal-like' markers and both cyclin D1 overexpression (P<0.0001) and CCND1 amplification (P<0.0001). On univariate analysis cyclin D1 expression showed a correlation with longer overall survival (OS). Neither cyclin D1 nor CCND1 were independent prognostic factors for disease-free survival or OS. The results of this study confirm the association between cyclin D1 overexpression and positivity for hormone receptors and the lack of CCND1 amplification in basal-like breast carcinomas.

SP4, a Novel Anti-Cyclin D1 Rabbit Monoclonal Antibody, Is a Highly Sensitive Probe for Identifying Mantle Cell Lymphomas Bearing the t(11;14)(q13;q32) Translocation

Immunohistochemistry is the most widely used approach in the diagnosis of mantle cell lymphoma (MCL). However, its reliability may be hampered by several technical reasons, necessitating the use of alternative techniques such as the identification of the t(11;14)(q13;q32) translocation to characterize such lesions. The authors compared two monoclonal antibodies (DCS-6 and SP4) for assessing cyclin D1 immunoreactivity in a series of 22 MCLs. Their results documented that SP4, a novel rabbit monoclonal antibody, is more effective than the mouse monoclonal antibody DCS-6, one of the most commonly used reagents in daily practice. Although DCS-6 and SP4 were capable of identifying cyclin D1 immunoreactivity in 95.4% and 100% of the cases analyzed, respectively, the prevalence of cyclin D1 immunoreactive neoplastic cells was significantly (P < 0.0001) higher with SP4 (86.6 +/- 13.1%) than with DCS-6 (39.8 +/- 32%). Moreover, the staining intensity was faint in 16 (76.2%) cases and moderate to strong in 5 (23.8%) cases immunostained with DCS- 6, while all the cases showed a moderate to strong immunoreactivity with SP4 (P < 0.0001). According to an arbitrary score based on the percentage of immunoreactive neoplastic cells and staining intensity, only 10 (45.4%) cases were considered high cyclin D1 expressors after staining with DCS-6, whereas all the cases were high expressors with SP4 (P < 0.0001). These data provide evidence that the SP4 monoclonal antibody may be a fast, easy-to-interpret, and reliable surrogate for the detection of the (11;14) translocation by molecular techniques.

Paraffin section interphase fluorescence in situ hybridization in the diagnosis and classification of non-hodgkin lymphomas

Cytogenetic data can contribute valuable information that may assist in the diagnosis and classification of non-Hodgkin lymphomas and may in some cases also provide prognostic information. Interphase fluorescence in situ hybridization (FISH) studies offer the ability to assess for characteristic cytogenetic abnormalities even when material for standard metaphase cytogenetic analysis is not available. This review discusses the use of FISH in paraffin-embedded material with particular attention paid to the use of intact thin paraffin sections. The basic principles of FISH analysis are summarized, the advantages and disadvantages of analysis of thin paraffin sections rather than intact nuclei are discussed, and the more commonly encountered artifacts are considered. Each of the well-characterized cytogenetic abnormalities that are associated with particular types of non-Hodgkin lymphoma and can be detected with commercially available FISH probes is discussed individually. In particular, their incidence in various types of lymphoma is reviewed, the types of commercially available FISH probes to detect such abnormalities are discussed, and clinical situations where such analysis can be of diagnostic utility are described.

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.

Consistent immunostaining for cyclin D1 can be achieved on a routine basis using a newly available rabbit monoclonal antibody

Rabbit monoclonal antibody (MAb), which has become available only recently, theoretically combines the advantage of the high affinity attributable to its rabbit origin and the high specificity due to its monoclonal nature. Since immunohistochemical demonstration of cyclin D1 is notoriously difficult, this study aims to assess whether a newly available rabbit MAb against cyclin D1 (SP4) can improve the consistency of immunostaining, especially for the diagnosis of mantle cell lymphoma (MCL). A total of 150 cases of lymphoproliferative lesions, including 30 cases of MCL, histologic mimickers of MCL, and various types of lymphomas and leukemias, were studied. Immunostaining was performed on formalin-fixed, paraffin-embedded tissue sections using a labeled streptavidin-biotin peroxidase system in an automated immunostainer. All cases of MCL expressed cyclin D1, with a higher median staining score (8 out of a maximum of 12) compared with mouse MAb DCS-6 (score 4). In addition, 2 of 15 cases of B-cell chronic lymphocytic leukemia (B-CLL), 3 of 12 cases of multiple myeloma, and 2 of 5 cases of hairy cell leukemia were also positive. Comparable staining results could also be achieved by an optimized manual staining protocol. This study thus confirms the superior performance of the rabbit MAb SP4, which should permit consistent immunostaining for cyclin D1 to be readily achieved. The value of cyclin D1 immunohistochemistry in the differential diagnosis of MCL from other low-grade B-cell lymphomas is also affirmed, but with the caveat that rare cases of B-CLL can also be cyclin D1 positive.

Topoisomerase IIα expression in mantle cell lymphoma: a marker of cell proliferation and a prognostic factor for clinical outcome

Mantle cell lymphoma (MCL) is a malignant lymphoma associated with a relatively aggressive clinical course and a median overall survival time of 3-4 years. Treatment usually consists of combination chemotherapy, often including topoisomerase (topo) inhibitors such as doxorubicin, etoposide and mitoxantrone. Topo IIalpha is an enzyme that is needed whenever uncoiling of DNA is necessary during the cell cycle. The enzyme is a marker of cell proliferation. We analyzed the expression of topo IIalpha in relation to Ki-67 and the clinical outcome in patients with MCL. Biopsy specimens from 95 untreated patients enrolled in two multicenter trials (1975-1985) were investigated immunohistochemically with monoclonal antibodies against topo IIalpha (Ki-S4) and Ki-67 (Ki-S5). Patients with low (0-10%) topo IIalpha expression had a median overall survival time of 49.0 months, compared to 17.0 months for patients with high (more than 10%) topo IIalpha expression. The Kaplan-Meier analysis showed a significant difference in the overall survival time related to the percentage of topo IIalpha (P<0.001) and Ki-67 (P<0.001) positive tumor cells. Multivariate Cox regression analysis revealed the expression of topo IIalpha as the most important prognostic factor (P<0.001) in MCL superior to the international prognostic index (IPI), the Ki-67 index and other clinical characteristics.

Relationship between cyclin D1 and p21(Waf1/Cip1) during differentiation of human myeloid leukemia cell lines

Expression of cell cycle-regulating genes was studied in human myeloid leukemia cell lines ML-1, ML-2 and ML-3 during induction of differentiation in vitro. Myelomonocytic differentiation was induced by phorbol ester (12-o-Tetradecanoyl-phorbol-13-acetate, TPA), tumor necrosis factor alpha (TNFalpha) or interferon gamma (INFgamma), or their combination. Differentiation (with the exception of TNFalpha alone) was accompanied by inhibition of DNA synthesis and cell cycle arrest. Inhibition of proliferation was associated with a decrease in the expression of cdc25A and cdc25B, cdk6 and Ki-67 genes, and with increased p21(Waf1/Cip1) gene expression, as measured by comparative RT-PCR. Expression of the following genes was not changed after induction of differentiation: cyclin A1, cyclin D3, cyclin E1 and p27(Kip1). Surprisingly, cyclin D1 expression was upregulated after induction by TPA, TNFalpha with IFNgamma or BA. Cyclin D2 was upregulated only after induction by BA. The results of the expression of the tested genes obtained by comparative RT-PCR were confirmed by quantitative real-time (RQ) RT-PCR and Western blotting. Quantitative RT-PCR showed as much as a 288-fold increase of cyclin D1 specific mRNA after a 24h induction by TPA. The upregulation of cyclin D1 in differentiating cells seems to be compensated by the upregulation of p21(Waf1/Cip1). These results, besides others, point to a strong correlation between the expression of cyclin D1 and p21(Waf1/Cip1) on the one hand and differentiation on the other hand in human myeloid leukemic cells and reflect a rather complicated network regulating proliferation and differentiation of leukemic cells.

Mantle cell lymphoma: improved diagnostics using a combined approach of immunohistochemistry and identification of t(11;14)(q13;q32) by polymerase chain reaction and fluorescence in situ hybridization

INTRODUCTION

Mantle cell lymphoma (MCL) is a clinicopathological entity characterized by an aggressive clinical course, morphological features, and overexpression of cyclin D1 due to juxtaposition of the bcl-1 locus (and CCND1 gene coding for the cyclin D1) to the IgH gene. This phenomenon is caused by t(11;14)(q13;q32). The morphological diagnosis of MCL may pose difficulties. Ancillary methods are available to support the diagnosis.

PATIENTS AND METHODS

We studied a group of 32 patients with MCL; 24 men and 8 women. The median age at the diagnosis was 64 years. We characterized the investigated group by histology, and to analyze the immunohistochemical (IHC) profile we used a panel of antibodies including anti-cyclin D1. Polymerase chain reaction (PCR) was used to detect the rearrangement of bcl-1/IgH in 26 cases (in 11 patients, the DNA was isolated from frozen tissues or from nucleated cells of bone-marrow aspirate or peripheral blood, in 15 patients we utilized paraffin-embedded material). Dual color fluorescence in situ hybridization (FISH) on interphase nuclei detecting the t(11;14)(q13;q32) was applied in all 32 cases.

RESULTS

Cyclin D1 IHC was positive in 29 of 30 cases tested (97%). In six, the result was weak and difficult to rely on to support the diagnosis. PCR revealed the fusion gene in 14 of the 26 cases (54%). The best yield was obtained from fresh and frozen samples (8 of 11 positive). Using FISH, we identified the translocation in all 32 patients, the findings being easily interpretable in 29 patients. In three cases, the intensity of red and green signals was weaker and difficult to read though the co-hybridized signals were identified. The classical pattern of the translocation was observed in 26 patients, while in 3 we found variant patterns suggesting a loss of the V segment of the IgH gene (2x) and a shift in the breakpoint region at chromosome 11 (1x).

CONCLUSION

The diagnosis of MCL should be supported by a complex laboratory approach. Interphase FISH seems a useful complementary method to morphology and IHC. It is applicable to various tissues and cells prepared as tissue imprints or histological sections.

Catalyzed signal amplification for cyclin D1 detection in mantle cell lymphoma

Mantle cell lymphoma is characterized by a t(11;14)(q13;q32) translocation resulting in cyclin D1 protein overexpression. Immunohistochemical detection of the latter, therefore, is a useful marker for the diagnosis of mantle cell lymphoma. Nevertheless, interpretation of results is often hampered by the weak immunoreactivity obtained with routine detection techniques. This problem can be overcome by resorting to highly sensitive catalyzed signal amplification methods based on peroxidase-catalyzed deposition of a biotinylated phenolic compound. The present study compares the results obtained with catalyzed signal amplification, labeled streptavidin biotin, and dextran polymeric conjugate (EnVision+) techniques in cyclin D1 demonstration in mantle cell lymphoma. The study was performed on formalin-fixed, paraffin-embedded archival tissue from 20 mantle cell lymphoma cases. Ten cases of small lymphocytic lymphoma and 10 instances of follicular center cell lymphoma were used as controls. Antigen retrieval was done by autoclaving under controlled pressure (2 bar) and temperature (120 degrees C) conditions. The best results were obtained after 1 minute of exposure with catalyzed signal amplification and after 6 minutes with other detection systems. Regarding cyclin D1 expression in mantle cell lymphoma cases, 17 (85%) were weakly positive and 3 (15%), moderately positive with labeled streptavidin biotin, whereas 15 (75%) were weakly positive and 5 (25%) moderately positive with EnVision+. In contrast, all 20 mantle cell lymphoma cases were strongly cyclin D1 positive with catalyzed signal amplification. No evidence of cyclin D1 immunostaining was obtained in any of the small lymphocytic lymphoma and follicular center cell lymphoma instances with any of the three methods used. In conclusion, catalyzed signal amplification methods provide a very useful tool for cyclin D1 demonstration in cases in which other immunohistochemical techniques yield inconclusive results.

Detection of cyclin D1 in B cell lymphoproliferative disorders by flow cytometry

AIMS

To describe and revise a flow cytometric assay for evaluating cyclin D1 overexpression in B cell lymphoproliferative disorders (B-LPDs).

METHODS

Cyclin D1 expression was evaluated in 11 healthy controls and 51 patients with B-LPD by flow cytometry using the 5D4 monoclonal antibody. In 25 cases, experiments were repeated up to four times with mononuclear cells (MNC) fixed in ethanol for 1-120 days to evaluate the consistency of cyclin D1 expression. Flow cytometry results were compared with fluorescence in situ hybridisation (FISH) for the t(11;14) translocation in 19 patients and with immunohistochemistry (IHC) using the DCS-6 monoclonal antibody in nine patients.

RESULTS

A mean fluorescence intensity ratio (MFIR) of 4.8 was defined as the cut off point for positivity based on cyclin D1 expression in healthy controls (mean + 3 SD). Ten patients overexpressed cyclin D1 by flow cytometry. These included five of eight patients with mantle cell lymphoma, four of 19 with chronic lymphocytic leukaemia, and one with follicular lymphoma. MFIR in the repeat experiments differed less than 25% in 20 of 25 patients and in no cases did it cross the cut off point. There was a good correlation between cyclin D1 expression by flow cytometry and FISH for t(11;14) in 15 of 19 patients and six of nine had concordant results with flow cytometry, FISH, and IHC.

CONCLUSION

Cyclin D1 expression remains fairly stable once MNC are fixed in ethanol and the flow cytometric assay can be used for the routine screening of B-LPD. Further comparisons between flow cytometry, IHC, and FISH may be needed to ascertain the diagnostic value of the flow cytometric assay.

Determination of cyclin D1 and CD20 mRNA levels by real-time quantitative RT-PCR from archival tissue sections of mantle cell lymphoma and other non-Hodgkin's lymphomas

Cyclin D1 overexpression is a valuable marker for the diagnosis of mantle cell lymphoma (MCL). We used a real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) method to quantify levels of cyclin D1, CD20, and cyclophilin A mRNA in manually microdissected, paraffin-embedded tissue sections using an ABI 7700 qRT-PCR system. The study group included 21 cases of MCL and 37 cases of other types of B-cell non-Hodgkin's lymphoma. Cyclin D1 mRNA copy number was normalized to CD20 and cyclophilin A mRNA and evaluated statistically by analysis of variance. The relative cyclin D1 levels were similar whether normalized to CD20 or cyclophilin A, indicating that CD20 levels are stable and can be used as a B-cell-specific normalizer. Statistically significant differences were found in the median levels of cyclin D1 mRNA (expressed as % CD20 mRNA) among cases of MCL (87.6), small lymphocytic lymphoma (9.9), follicular lymphoma (2.4), diffuse large B-cell lymphoma (5.9), marginal zone B-cell lymphoma (39.8), and Burkitt lymphoma (7.1) (P < 0.05). We conclude that qRT-PCR can be used to quantify cyclin D1 mRNA levels in archival tissue sections. Normalization of cyclin D1 to a B-cell-specific marker more accurately reflects overexpression by MCL than other methods that normalize using constitutively expressed mRNA species.

Identification of novel regions of amplification and deletion within mantle cell lymphoma DNA by comparative genomic hybridization

We have carried out comparative genomic hybridization (CGH) analysis on archival biopsy material from a series of 30 UK mantle cell lymphomas. The most frequent aberrations were gains of 3q (21 cases), 6p (19 cases), 7q (8 cases), 12p (8 cases), 12q (9 cases) and 17q11q21 (8 cases), and losses of 1p13p32 (10 cases), 5p13p15.3 (9 cases), 6q14q27 (11 cases), 8p (7 cases), 11q13q23 (8 cases) and 13q (18 cases). Nineteen cases (63%) had a common region of amplification at 3q28q29, which was highly amplified in three cases, suggesting the presence of a mantle cell lymphoma (MCL)-related oncogene in this region. There was a minimal common region of deletion at 6q25q26 in nine cases (30%). No MCL-specific locus has previously been identified on chromosome 6 and this region may contain a tumour suppressor gene specifically implicated in the development of this subtype of lymphoma. An increased number of chromosome aberrations, gain of Xq and loss of 17p were all significantly associated with a worse prognosis. A greater understanding of the genetics of mantle cell lymphoma may allow the identification of prognostic factors which will aid the identification of appropriate treatment regimens.

Cyclin D1 as an aid in the diagnosis of mantle cell lymphoma in skin biopsies: a case report

Mantle cell lymphoma (MCL), an uncommon and aggressive form of non-Hodgkin lymphoma, typically involves lymph nodes. It usually only secondarily involves extranodal sites. We describe an unusual case of a MCL that presented and relapsed in the earlobes. Light microscopic findings were initially regarded as suggestive of small lymphocytic lymphoma, although subsequent analysis of fresh tissue by flow cytometry led to the diagnosis of MCL. Retrospective application of a broad panel of recently developed markers suitable for analysis of routinely processed tissue yielded results that also permitted a diagnosis of MCL. If these results had been available at the time of initial presentation, they would have obviated the need for rebiopsy. Greater awareness not only of the phenotypic criteria by which lymphomas are classified but of the lymphoma markers available for evaluation of routinely processed tissue should facilitate the accurate diagnosis of diseases like MCL and minimize the risk of misdiagnosis as an indolent disorder.

Cyclophosphamide/fludarabine (CF) is active in the treatment of mantle cell lymphoma

The purpose of this study was to determine the efficacy and toxicity of the cyclophosphamide and fludarabine (CF) regimen in patients with newly diagnosed and relapsed/refractory mantle cell lymphoma (MCL). Thirty patients with pathologically confirmed MCL were treated with the CF regimen. Ten (33%) had no prior therapy, six (20%) had one previous regimen, and 14 (47%) received two or more prior regimens. Ninety cycles of CF with a median of 3 cycles/patient (range, 1-5 cycles) were administered to patients with MCL. Nine patients (30%) had a complete response (CR) and 10 (33%) had a partial response (PR) for an overall response rate (RR) of 63%. The median failure-free survival (FFS) and overall survival (OS) was 4.8 months and 17.5 months, respectively. When patients were analyzed based upon the number of previous treatments (0, 1, or 2 or more), those with no previous treatment (n=10) had an overall response of 100%, with 70% CR. The median FFS was 28.1 months and the median OS for this group has not been reached at 42.3+ months. Hematologic and infectious toxicity were the major toxicities encountered with the CF regimen. Grade 3-4 neutropenia, thrombocytopenia and anemia were seen in 50%, 37%, and 36% of patients, respectively. There were 13 episodes of grade 3 infections. There was no treatment related mortality, In conclusion, the high response rate associated with the CF regimen merits further investigation in previously untreated patients with MCL, particularly in those who are not candidates for aggressive therapy.

Lymphoma immunophenotyping: a new era in paraffin-section immunohistochemistry

Recent advances in immunohistochemistry have made it possible to investigate lymphomas for the expression of a wide range of antigens in fixed tissues. Epitope retrieval, sensitive detection methods, and the availability of new monoclonal antibodies have all contributed to one's ability to perform detailed immunophenotyping that previously could only be done in cryostat sections or by flow cytometry. Current lymphoma classifications make use of characteristic immunophenotypic profiles that aid in the reproducible diagnosis and subcassification of these neoplasms. The following is a review of the current state of immunophenotyping for lymphoid neoplasms in fixed tissues.

In situ hybridization and reverse transcription-polymerase chain reaction for cyclin D1 mRNA in the diagnosis of mantle cell lymphoma in paraffin-embedded tissues

Mantle cell lymphoma (MCL) is characterized by the chromosomal translocation t(11;14), which involves rearrangement of the bcl-1 proto-oncogene to the immunoglobulin heavy chain gene and results in overexpression of cyclin D1 mRNA. In this study, we evaluated the diagnostic relevance of three methods that may be helpful in the diagnosis of MCL: in situ hybridization (ISH) and a stringent reverse transcriptase-polymerase chain reaction (RT-PCR) protocol for cyclin D1 mRNA, and immunohistochemistry for cyclin D1 protein. The study group included 37 paraffin-embedded specimens (25 from lymph nodes and 12 from extranodal tissues) from 30 patients. MCL diagnosis was performed according to the Revised European-American Classification of Lymphoid Neoplasms. Twenty-nine patients with non-MCL lymphoproliferative disorders comprised the control group. Biotin-labeled ISH was performed in 28 cases of MCL, 24 (86%) of which were found to be positive. As shown by ISH in extranodal tissues, cyclin D1 mRNA was present not only in neoplastic lymphoid cells, but in other cell types as well. For this reason, RT-PCR results were considered reliable for MCL diagnosis only on informative material (from tissues that do not normally express cyclin D1); this method was evaluated as positive in 16 of 18 (89%) MCL cases. Cyclin D1 immunopositivity was present in 20 of 29 (69%) MCL cases. No members of the control group were found to express cyclin D1 mRNA by either ISH or RT-PCR under the stringent conditions used. In conclusion, stringent RT-PCR for cyclin D1 expression can be helpful in MCL diagnosis in paraffin-embedded material from lymph nodes. ISH is a sensitive method for cyclin D1 mRNA detection; its sensitivity is superior to that of cyclin D1 immunohistochemistry and similar to that of the stringent RT-PCR used. ISH is very specific as well, clearly more specific than RT-PCR, because it allows the correlation of molecular findings with morphology. This method can be applied on all types of paraffin-embedded tissues and provides an accurate tool for MCL diagnosis.

Quantitative Real-Time Reverse Transcription-PCR Assay for Cyclin D1 Expression: Utility in the Diagnosis of Mantle Cell Lymphoma

Background: The t(11;14)(q13;q32) translocation present in the majority of mantle cell lymphomas (MCLs) places the cyclin D1 gene under the control of immunoglobulin transcriptional regulatory elements, causing overexpression of cyclin D1. Quantification of cyclin D1 expression can distinguish MCL from other lymphomas.

Methods: A quantitative real-time reverse transcription (RT)-PCR assay was developed for cyclin D1 mRNA suitable for use with RNA extracted from fresh and formalin-fixed, paraffin-embedded tissues. Specimens were amplified in an Applied Biosystems Model 7700 Sequence Detection System in reactions containing primers and probes for cyclin D1 and a control gene, β2-microglobulin. Relative expression of the two genes was standardized against a control MCL cell line, M02058.

Results: The range of cyclin D1 expression among 20 MCLs was substantially higher than that in other lymphomas and reactive lymph nodes. By choosing an optimal cutoff point for assessing overexpression, the sensitivity and specificity of the assay for the diagnosis of MCL in lymph node specimens both approached 100%: Overexpression was detected in 20 of 20 MCLs, but in none of 21 non-mantle-cell lymphomas or 10 reactive lymph nodes.

Conclusions: Quantitative real-time RT-PCR for cyclin D1 overexpression provides a rapid diagnostic test with clinical utility in the diagnosis of MCL.

Immunohistochemical detection of cyclin D1 using optimized conditions is highly specific for mantle cell lymphoma and hairy cell leukemia

Mantle cell lymphoma (MCL) is more aggressive when compared with other lymphomas composed of small, mature B lymphocytes. Cyclin D1 is overexpressed in MCL as a result of the translocation t(11;14)(q13;q32). Cyclin D1 immunohistochemistry in fixed, paraffin-embedded tissue contributes to the precise and reproducible diagnosis of MCL without the requirement of fresh tissue. However, its use in bone marrow biopsies is not well established. In addition, increased levels of cyclin D1 mRNA have been found in hairy cell leukemia but have not consistently been detected by immunohistochemistry. We used a polyclonal antibody and heat-induced antigen retrieval conditions to evaluate 73 fixed, paraffin-embedded bone marrow, spleen, and lymph node specimens with small B-cell infiltrates, obtained from 55 patients. Cyclin D1 was overexpressed in 13/13 specimens of MCL (usually strong, diffuse reactivity in most tumor cells) and in 14/14 specimens of hairy cell leukemia (usually weak, in a subpopulation of tumor cells). No reactivity was detected in five cases of B-chronic lymphocytic leukemia; five cases of splenic marginal zone lymphoma; six cases of nodal marginal zone cell lymphoma; two cases of gastric marginal zone cell lymphoma; or ten benign lymphoid infiltrates in bone marrow, spleen, or lymph nodes. In summary, although the total number of studied cases is small and a larger series of cases may be required to confirm our data, we present optimized immunohistochemical conditions for cyclin D1 in fixed, paraffin-embedded tissue that can be useful in distinguishing MCL and hairy cell leukemia from other small B-cell neoplasms and reactive lymphoid infiltrates.

Multiparameter immunohistochemical analysis of the cell cycle proteins cyclin D1, Ki-67, p21WAF1, p27KIP1, and p53 in mantle cell lymphoma

BACKGROUND

Mantle cell lymphoma (MCL) is characterized by overexpression of cyclin D1, a G1 cyclin that participates in the control of cell cycle progression at the G1 to S phase transition. In addition to cyclin D1, other cell cycle regulatory molecules may be involved in the proliferation and progression of MCL. Mutation of p53, deletion of p16(INK4a), and loss of p21(WAF1) expression have been reported in some cases of blastoid MCL.

OBJECTIVE

We sought to examine levels of expression of these proteins in typical and blastoid MCL and to determine whether differences were present between these subtypes of lymphomas.

DESIGN

A retrospective series of typical and blastoid MCLs was evaluated for expression of the cell cycle-related proteins cyclin D1, p21(WAF1), p27(KIP1), Ki-67, and p53, as well as mitotic index. Paraffin-embedded archival tissues from 24 MCL specimens (17 typical, 7 blastoid) were immunostained with antibodies to p21(WAF1), p27(KIP1), p53, Ki-67, and cyclin D1. The percentage of positive cells for each specimen was estimated by counting 1500 cells under oil immersion microscopy. Levels of antigen expression were compared for the typical and blastoid MCLs. The mitotic index was estimated using twenty 100x oil immersion fields (OIFs) for each specimen.

RESULTS

Cyclin D1 expression was seen in 22/24 specimens (92%). Blastoid MCLs were characterized by a significantly higher mean mitotic index (>20 mitoses/20 OIFs) and Ki-67 index (>45%) when compared with typical MCLs (P <.001 and P <.008, respectively; Fisher's exact test). High expression of p27(KIP1) (>25% staining) was seen more frequently in typical MCLs than in the blastoid variants (P =.03; Fisher's exact test). No significant differences were found between typical and blastoid MCLs for the expression of p21(WAF1) or p53.

CONCLUSIONS

A significantly higher mitotic index and Ki-67 index were found in blastoid MCLs as compared with typical MCLs. Low p27(KIP1) expression was associated with the blastoid MCL variant. These findings confirm the high proliferative nature of blastoid MCL and suggest a role for p27(KIP1) in the negative regulation of the cell cycle in MCL.

Diagnostic utility of fluorescence in situ hybridization in mantle-cell lymphoma

Mantle-cell lymphoma (MCL) has a poorer prognosis than other small B-cell lymphomas, thus a definitive diagnosis is essential. The t(11;14)(q13;q32) associated with MCL juxtaposes portions of CCND1 (11q13) and IGH (14q32), resulting in over-expression of cyclin D1. In this study, a highly sensitive two-colour fluorescence in situ hybridization (FISH) method was developed to detect t(11;14)(q13;q32) in nuclei isolated from paraffin-embedded tissue. Twenty-three MCLs, 13 normal controls and nine small B-cell lymphomas other than MCL were studied by FISH. Each MCL had been previously investigated to detect genomic IGH-CCND1 fusion by polymerase chain reaction (PCR) using DNA extracted from frozen tissue. The IGH-CCND1 fusion detection rate in the MCLs was 96% by FISH compared with 35% by PCR. By FISH, one MCL and three small B-cell lymphomas other than MCL harboured abnormalities involving only IGH. Less than 1% of cells showed false-positive IGH-CCND1 fusion in normal specimens by FISH. Thus, this highly sensitive FISH assay is very useful in confirming the diagnosis of MCL, has wide applicability as it may be performed on both paraffin-embedded and fresh tissue, and may also facilitate detection of translocations involving these loci in tumours other than MCL.

Optimized cyclin D1 immunoperoxidase staining in mantle cell lymphoma

Mantle cell lymphoma (MCL) has a worse prognosis than MALT lymphoma (MALTL). Distinction between MCL and MALTL on purely morphologic grounds can be difficult. Cyclin D1 (PRAD1/bcl1) is overexpressed in MCL as a result of a t(11:14) gene rearrangement, which leads to overexpression of cyclin D1 mRNA and protein. The immunohistochemical detection of cyclin D1 in MCL has been reported by several authors to be highly specific with sensitivity ranging from 70%-100%, but diagnostic laboratories have reported difficulty in finding a reliable method for cyclin D1 immunostaining. The aim of this study was to evaluate and optimize a method for detection of cyclin D1 by paraffin section immunoperoxidase staining. Sections of routinely processed tissue from five MCL and one splenic marginal zone lymphoma (MZL) were immunostained using a mixture of two primary monoclonal antibodies and a standard avidin-streptavidin method. Antigen retrieval was performed using 1) steam heat in citrate buffer, 2) as in "1" followed by sonication for one minute, and 3) as in "2" followed by enzymatic digestion. All the above were repeated, with the additional use of catalyzed signal amplification (CSA). Later, sections of the same cases, plus three MALTL were immunostained as in "2". Steam heat antigen retrieval alone produced the best results. All MCL showed positive nuclear staining while the MZL and all MALTL were negative. Sonication did not enhance staining noticeably, whereas enzymatic digestion produced cytoplasmic staining. CSA increased background staining with no significant gain in nuclear stain intensity. We conclude that cyclin D1 immunostaining of formalin-fixed, paraffin-embedded tissue can be reliably achieved by heat induces antigen retrieval and a cocktail of two monoclonal antibodies.

Increased proteasome degradation of cyclin-dependent kinase inhibitor p27 is associated with a decreased overall survival in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive neoplasm characterized by the deregulated expression of cyclin D1 by t(11;14). The molecular mechanisms responsible for MCL's clinical behavior remain unclear. The authors have investigated the expression of p53, E2F-1, and the CDK inhibitors p27 and p21 in 110 MCLs, relating their expression to proliferative activity (Ki-67). For comparison, they have similarly analyzed low-grade (12 MALT, 16 CLL/SLL) and high-grade (19 DLCL) lymphomas. p53 was detected more frequently in large-cell MCL (l-MCL; 5 of 7) than in classical MCL (s-MCL; 13 of 103) and DLCL (8 of 19). In MCL and DLCL, the percentage of E2F-1+ nuclei was high, correlating with high Ki-67 expression. Most MCLs (91 of 112) and DLCLs (12 of 19) showed a loss of p27; MALT and CLL/SLL, however, were p27 positive. Reverse transcription–polymerase chain reaction and in vitro protein degradation assays demonstrated that MCLs have normal p27 mRNA expression but increased p27 protein degradation activity via the proteasome pathway. Correlation of MCL p53 and p27 expression with clinical data showed an association between reduced overall survival rates and the overexpression of p53 (P = .001), the loss of p27 (P = .002), or both. Loss of p27 identified patients with a worse clinical outcome among p53 negative cases (P = .002). These findings demonstrated that MCL has a distinct cell cycle protein expression similar to that of high-grade lymphoma. The loss of p27 and the overexpression of p53 in MCL are prognostic markers that identify patients at high risk. The demonstration that low levels of p27 in MCL result from enhanced proteasome-mediated degradation should encourage additional clinical trials. (Blood. 2000;95:619-626)

Molecular Characterization of 11q Deletions Points to a Pathogenic Role of the ATM Gene in Mantle Cell Lymphoma

Deletions involving the long arm of chromosome 11 (11q) have been recently found as recurrent chromosome aberrations in mantle cell lymphoma (MCL). In the current study, the incidence and molecular extent of 11q deletions were analyzed in a series of 81 MCL by fluorescence in situ hybridization with probes from a contiguous set of yeast artificial chromosomes (YACs). Loss of chromosome 11 material was observed in 37 of 81 cases (46%). The minimally deleted segment comprised YAC 801e11 containing the ATM gene. To further narrow the minimal region of loss, P1-derived artificial chromosomes mapping to the critical region were isolated and used as probes in cases without aberrations detectable with YACs. This allowed the identification of an ATM deletion that was beyond the resolution of YAC probes. The identification of a minimally deleted segment affecting ATM suggests a pathogenic role of ATMas a tumor suppressor gene in MCL.

Molecular Characterization of 11q Deletions Points to a Pathogenic Role of the ATM Gene in Mantle Cell Lymphoma

Deletions involving the long arm of chromosome 11 (11q) have been recently found as recurrent chromosome aberrations in mantle cell lymphoma (MCL). In the current study, the incidence and molecular extent of 11q deletions were analyzed in a series of 81 MCL by fluorescence in situ hybridization with probes from a contiguous set of yeast artificial chromosomes (YACs). Loss of chromosome 11 material was observed in 37 of 81 cases (46%). The minimally deleted segment comprised YAC 801e11 containing the ATM gene. To further narrow the minimal region of loss, P1-derived artificial chromosomes mapping to the critical region were isolated and used as probes in cases without aberrations detectable with YACs. This allowed the identification of an ATM deletion that was beyond the resolution of YAC probes. The identification of a minimally deleted segment affecting ATM suggests a pathogenic role of ATMas a tumor suppressor gene in MCL.

Differential expression of cyclin D1 in mantle cell lymphoma and other non-Hodgkin's lymphomas

Mantle-cell lymphomas are associated with a characteristic chromosomal translocation, t(11;14)(q13;q32). This translocation involves rearrangement of the bcl-1 proto-oncogene from chromosome 11 to the immunoglobulin heavy chain gene on chromosome 14, resulting in an overexpression of cyclin D1 mRNA (also known as bcl-1 and PRAD1). In the current study performed on paraffin-embedded tissue, cyclin D1 mRNA could be detected in 23 of 24 mantle-cell lymphomas by reverse transcription polymerase chain reaction (RT-PCR) whereas only 9 of 24 demonstrated a t(11;14) by PCR. However, we also found that cyclin D1 mRNA could be detected in the majority (11 of 17, 65%) of non-mantle-cell lymphomas and in a minority of atypical lymphoid hyperplasias (3 of 7, 43%). Cyclin D1 mRNA expression was not observed in floridly reactive lymph nodes (0 of 9) or in unstimulated lymph nodes (0 of 20), suggesting that it is a sensitive adjunct marker for malignant lymphoproliferative processes, but not specific for mantle-cell lymphoma. A semiquantitative RT-PCR assay was developed that compared the ratio of cyclin D1 to the constitutively expressed gene beta2-microglobulin. Using this assay on a limited number of our specimens, cyclin D1 overexpression in mantle-cell lymphoma could be reliably distinguished from its expression in other non-Hodgkin's lymphomas. This assay for cyclin D1 expression, designed for formalin-fixed, paraffin-embedded tissue, was a very sensitive and specific marker for mantle-cell lymphoma.

The cytomorphological spectrum of mantle cell lymphoma is reflected by distinct biological features

Mantle cell (centrocytic) non-Hodgkin's lymphoma (MCL) is a malignant tumour with unique biological features. The pathogenesis of MCL seems to be strongly associated with aberrant function of the cell cycle. 110 cases of MCL have been analysed for their cytomorphological features, mitotic and proliferation indices, bcl-1 rearrangements, p53 expression patterns and DNA content by both interphase cytogenetic as well as DNA flow cytometric analyses. According to cytomorphology, three subtypes were recognized: a common, a lymphoblastoid and a pleomorphic variant of MCL. Blastic MCL subtypes were characterized by distinctly elevated mitotic and proliferation indices, frequent bcl-1 rearrangements at the MTC locus, and overexpression of p53. The most interesting finding, however, was a striking tendency of blastoid MCL subtypes to harbour chromosome numbers in the tetraploid range, a feature clearly separating these neoplasms from other types of B-cell NHL and possibly being related to its unphysiological expression of cyclin D1. Although characterised by a uniform immunophenotype and common biological background, MCL shows a broad spectrum of morphological features ranging from small cell to blastic types, and this spectrum is mirrored by distinct biological features.

The blastic variant of mantle cell lymphoma arising in Waldeyer's tonsillar ring

We present three cases of blastic mantle cell lymphoma with an unusual initial manifestation in Waldeyer's ring with methods for differentiating it from other blastic neoplasms of the head and neck. All cases presented with a feeling of fullness in the area of the mass. Morphologically, the tumours were blastic with a high mitotic rate (three to nine per high power field). All were B-cell phenotype with coexpression of CD43. In all cases cyclin D1 and bcl-2 were positive and CD23 negative. Blastic mantle cell lymphoma occurring in Waldeyer's tonsillar ring may be mistaken for other high grade haematopoietic neoplasms. Immunohistochemistry and awareness of this type of lymphoma are helpful in differentiating it from other neoplasms.

Molecular methods for detecting t(11;14) translocations in mantle-cell lymphomas

The t(11;14)(q13;q32) and its molecular counterpart, bcl1/JH, are characteristic of mantle-cell lymphomas (MCL). Molecular detection of the translocation is useful in diagnosis and classification, and also shows promise in detecting minimal residual disease. The purpose of this study was to determine the frequency of detecting bcl1/JH by polymerase chain reaction (PCR) compared with Southern blot analysis in cases proven by cytogenetic analysis to harbor t(11;14). Southern blot analysis using two probes targeting the major translocation cluster (MTC) and a third probe targeting the p94 region was performed, along with PCR using two different bcl1 MTC primers, on 18 cases of MCL known to have t(11;14). Southern blot analysis revealed bcl1 rearrangement in 13 of 18 cases (72%), 12 with MTC breakpoints and 1 with a p94 breakpoint. The 2.1-kb MTC probe "b" was superior to the smaller 700-bp probe "a" in detecting these rearrangements. The MTC translocation was identified by PCR in 10 of 12 cases, and both primer sets that were tested performed equally well. This study illustrates the frequency with which molecular methods detect known t(11;14) translocations in MCLs. These results may help clinical laboratory scientists optimize their procedure for detecting bcl1 translocations by molecular methods at initial diagnosis and for purposes of detecting minimal residual disease.

Expression patterns of cyclin D1 and related proteins regulating G1-S phase transition in uveal melanoma and retinoblastoma

BACKGROUND/AIMS

A checkpoint mechanism in late G1, whose regulation via loss of retinoblastoma protein (pRB) or p16, or overexpression of cyclin D1 or cyclin dependent kinase 4 (CDK4), has been proposed to constitute a common pathway to malignancy. The aims of this study were (a) to compare markers of cell cycle G1-S phase transition in an intraocular tumour with known pRB deficiency (retinoblastoma) and compare it with one with an apparently functional pRB (uveal melanoma); (b) to determine if one of these markers may have a role in the pathogenesis of uveal melanoma; and (c) to determine if there is a difference in cell cycle marker expression following treatment of uveal melanoma and retinoblastoma.

METHODS

90 eyes were enucleated from 89 patients for retinoblastoma (n = 24) or for choroidal or ciliary body melanoma (n = 66). Conventional paraffin sections were assessed for cell type and degree of differentiation. Additional slides were investigated applying standard immunohistochemical methods with antibodies specific for cyclin D1 protein, pRB, p53, p21, p16, BCL-2, and MIB-1.

RESULTS

Cyclin D1 protein and pRB were negative in retinoblastoma using the applied antibodies. In contrast, cyclin D1 protein expression was observed in 65% of uveal melanomas; a positive correlation between cyclin D1 cell positivity and tumour cell type, location, growth fraction, as well as with pRB positivity was observed. p53, p21, and p16 could be demonstrated in both tumours. An inverse relation between p53 and p21 expression was demonstrated in most choroidal melanomas and in some retinoblastomas. Apart from a decrease in the growth fractions of the tumours as determined by MIB-1, a significant difference in the expression of G1-S phase transition markers in vital areas of uveal melanoma and retinoblastoma following treatment with radiotherapy and/or chemotherapy was not observed.

CONCLUSION

Retinoblastomas and uveal melanomas, two tumours of differing pRB status, differ also in their immunohistochemical pattern for markers of the G1-S phase transition of the cell cycle. The results of the present study support the concept of (a) an autoregulatory loop between pRB and cyclin D1 in tumours with a functional pRB and the disruption of this loop in the presence of pRB mutation, as well as (b) a checkpoint mechanism in late G1, whose regulation via loss of p16 or pRB, or overexpression of cyclin D1 constitutes a common pathway to malignancy. Further, the results raise the possibility of cyclin D1 overexpression having a role in the pathogenesis of uveal melanoma.

Aberrations of the G1- and G1/S-regulating genes in human cancer

Deregulated cell proliferation is the hallmark of cancer, and convergent data from the fields of cell-cycle research and molecular oncology have revealed the key role played by abnormalities of the cell-cycle control genes in multistep tumorigenesis. Along with the p53-mediated DNA damage checkpoint, the G1-governing pathway of D-type cyclins, their partner cyclin-dependent kinases (Cdk), Cdk inhibitors, and the retinoblastoma protein constitute a functional unit and prominent oncogenic target. We have learned a great deal about the molecular basis of G1 phase progression and G1/S transition, their proto-oncogenic defects, and potential clinical significance including diagnostic and prognostic applications and new approaches to gene therapy of cancer.

Cyclin D1 Expression in Mantle Cell Lymphoma Is Accompanied by Downregulation of Cyclin D3 and Is Not Related to the Proliferative Activity

The cell cycle regulatory protein cyclin D1 is essential for G1-S phase transition in several epithelial and mesenchymal tissues but is apparently not essential in normal mature B cells. An overexpression of cyclin D1 is induced by the chromosomal translocation t(11; 14)(q13; q32), which characterizes non-Hodgkin's lymphomas (NHLs) of mantle cell type. We studied 26 cases of mantle cell lymphoma (MCL) for the expression of cyclins D1 and D3. A total of 23 lymphomas showed a nuclear staining for cyclin D1, whereas reactive B cells of residual germinal centers were constantly negative. When compared with cyclin D3, an inverse staining pattern emerged. Whereas the B cells of residual germinal centers reacted strongly positive for cyclin D3, there was low or missing expression of cyclin D3 in MCL cells. In other B-cell lymphomas (n = 55), including chronic lymphocytic leukemia, low-grade lymphomas of mucosa-associated lymphatic tissue, follicular lymphomas, and diffuse large B-cell lymphomas, no cyclin D1 expression could be detected and 89% of these cases displayed cyclin D3 positivity. Lymphoma cell lines harboring the t(11; 14) showed cyclin D1 protein but no or very low levels of cyclin D3; three other B-cell lines, a T-cell line, and peripheral blood lymphocytes strongly expressed cyclin D3 and reacted negatively for cyclin D1. We conclude that the chromosomal translocation t(11; 14) leads to an abnormal protein expression of cyclin D1 in the tumor cells of MCL and induces a consecutive downregulation of cyclin D3. In contrast to other B-NHLs, cyclin D1 and D3 expression in MCL is not related to the growth fraction.

Blastoid Variants of Mantle Cell Lymphoma: Frequent bcl-1 Rearrangements at the Major Translocation Cluster Region and Tetraploid Chromosome Clones

Sixty-four cases of mantle cell (centrocytic) non-Hodgkin's lymphomas have been analyzed for their cytomorphologic features, proliferation indices, bcl-1 rearrangements, p53 expression patterns, and DNA content by both interphase cytogenetic and DNA flow cytometric analyses. According to cytomorphology, three subtypes were recognized: a common, a lymphoblastoid, and a pleomorphic variant of mantle cell lymphoma (MCL). Blastoid MCL subtypes were characterized by distinctly elevated mitotic counts (57 and 51/10 HPF v 21/10 high-power fields in common MCL), proliferation indices (58% and 53% v 27% in common types, respectively; P < .001), frequent bcl-1 rearrangements at the major translocation cluster locus (59% v 40%), and overexpression of p53 (21% v 6%). However, the most interesting finding was a striking tendency of blastoid MCL subtypes to harbor chromosome numbers in the tetraploid range (36% of lymphoblastoid and 80% of pleomorphic types v 8% of common variants, P < .001), a feature clearly separating these neoplasms from other types of B-cell non-Hodgkin's lymphoma and possibly being related to cyclin D1 overexpression. Our data indicate that, although characterized by a uniform immunophenotype and common biologic background, MCL shows a broad spectrum of morphologic features ranging from small cell to blastoid types and that the morphologic spectrum is mirrored by distinct biologic features.

The value of immunohistochemistry on paraffin wax embedded tissue sections in the differentiation of small lymphocytic and mantle cell lymphomas

AIMS

To determine whether immunohistochemistry applied to paraffin wax embedded biopsy tissue can be used to distinguish between B-small lymphocytic lymphoma (B-SLL) and mantle cell lymphoma (MCL).

METHODS

Formalin fixed, paraffin wax embedded tissue blocks of 12 cases of B-SLL and 12 cases of MCL were retrieved from the files of the Department of Pathology, Southampton University Hospitals Trust. Following antigen retrieval, where appropriate, sections were stained for CD3, CD5, CD20, CD23, CD43, Cyclin D, PGP9.5, and MIB1 using a streptavidin-biotin complex technique.

RESULTS

CD20 stained the neoplastic cells of B-SLL and MCL, and CD3 labelled the reactive T cells in these tumours. In B-SLL, the T cells were generally dispersed among the tumour cells, whereas in MCL they often formed bands around tumour cell nodules. CD5 could be detected on T cells, following antigen retrieval. The level of expression on B cells of B-SLL and MCL was generally too low to allow detection in paraffin wax embedded tissues. CD23 stained B-SLL but not MCL. However, it could be detected in only five of the 12 cases of B-SLL. CD43 could be detected in most cases of B-SLL and MCL. It is not, therefore, of value in distinguishing between these tumours. It will, however, help in the differentiation of B-SLL and MCL from other low grade B cell lymphomas, such as follicle centre cell and marginal zone lymphomas. Cyclin D was expressed in all of the MCL but in none of the B-SLL. PGP9.5 showed reactivity in most cases of MCL and much weaker reactivity in B-SLL. The proliferation indexes of MCL were generally higher than those of B-SLL, as measured by MIB1 labelling. Both tumours, however, showed a wide range of values and considerable overlap.

CONCLUSION

Staining for Cyclin D is the most reliable immunohistochemical mean of differentiating between B-SLL an MCL. High levels of PGP9.5, expressed in MCL, may be related to the degradation of Cyclin D by the ubiquitin pathway.