PRAD1/Cyclin D1 gene overexpression in mantle cell lymphoma

Clinical and biological features of mantle cell lymphoma patients with co-expression of CD10 and BCL-6: a retrospective study

Background

Mantle cell lymphoma (MCL) with co-expression of CD10 and BCL-6 was scarcely reported, and its biological features were largely remained unknown. Thus, this study aimed to describe the clinical and biological features, as well as outcome of MCL patients with co-expression of CD10 and BCL-6.

Methods

A total of 104 cases of MCL who were admitted to our hospital between January 2011 and October 2018 were recruited. Those patients were diagnosed according to the 2016 World Health Organization (WHO) classification system for tumors of the hematopoietic and lymphoid tissues, in compliance with the results of cytomorphology and immunohistochemical analysis. Patients were followed up through telephone interviews, medical records. Differences in age, gender, leukocyte count, lactate dehydrogenase (LDH) level, beta-2 microglobulin (β2-MG) level and results of immunohistochemistry were analyzed. Then the event-free survival (EFS) rate and overall survival (OS) rate were performed by the Kaplan-Meier method and log-rank test.

Results

The results showed that, in total, 5 patients had superficial lymph node enlargement, 2 patients suffered from abdominal discomfort, and 1 patient’s red blood cell (RBC) count was abnormal at the time of diagnosis. All patients were in stage IV, 75% had bone marrow involvement, and 75% and 100% of patients had elevated levels of LDH and β2-MG, respectively. Three classic genes and five variants were involved in the 8 patients. MCL patients with the co-expression of CD10 and BCL-6 had higher Ki-67 index, white blood cell (WBC) count, LDH level, and β2-MG level than those of without co-expression of CD10 and BCL-6 (P=0.025, 0.038, 0.015, and 0.021, respectively). Besides, MCL patients with CD10 and BCL-6 co-expression had shorter OS and EFS (χ²=6.401 and 5.975; P=0.011 and 0.015, respectively), indicating patients’ susceptibility to get complex karyotype and TP53 abnormality.

Conclusions

MCL patients with co-expression of CD10 and BCL-6 were more likely to have bone marrow involvement, higher Ki-67 index, increased WBC count, and elevated levels of LDH and β2-MG at the time of diagnosis, then might has complex cytogenetic and poor prognosis.

Simultaneous presentation of orbital mantle cell lymphoma and endocrine mucin-producing sweat gland carcinoma

Mantle cell lymphoma is a rare malignancy to present in the orbit, comprising only 1-5% adnexal lymphomas. Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is an equally uncommon adnexal tumor of sweat gland origin that may present on the eyelid. Herein we present a case of a 77-year old man with no previous cancer history who presented with painless progressive left globe proptosis and an enlarging left upper lid margin lesion, ultimately determined upon biopsy to be simultaneous orbital mantle cell lymphoma with systemic involvement and isolated eyelid EMPSGC. The pathogenesis, clinical manifestation, and management for each rare disease entity are reviewed and concept of collision tumors is discussed.

Clinicopathological Features of Ocular Adnexal Mantle-Cell Lymphoma in an International Multicenter Cohort

Importance

To our knowledge, the clinical features of ocular adnexal mantle-cell lymphoma (OA-MCL) have not previously been evaluated in a large multicenter cohort.

Objective

To characterize the clinical features of OA-MCL.

Design, Setting, and Participants

This retrospective multicenter study included patient data collected from January 1, 1980, through December 31, 2015, at 6 eye cancer centers in 4 countries. Medical records of 55 patients with OA-MCL were reviewed; the median length of follow-up was 33 months.

Main Outcomes and Measures

Overall survival, disease-specific survival, and progression-free survival were the primary end points.

Results

Fifty-five patients were included; ocular adnexal MCL was found to be most common in older individuals (mean age, 70 years) and men (n = 42 of 55; 76%). Patients with OA-MCL frequently presented with disseminated lymphoma (n = 34 of 55; 62%), and were likely to experience stage IVE disease (n = 35 of 55; 64%), with bilateral involvement (n = 27 of 55; 47%), tumor masses (n = 27 of 36; 75%), and involvement of the orbit (n = 32 of 55; 58%). Chemotherapy with or without external beam radiation therapy was the most frequently used treatment. Overall survival rates for the entire cohort were 65% at 3 years (95% CI, 52%-78%) and 34% at 5 years (95% CI, 21%-47%). Disease-specific survival after 5 years was 38% for the entire cohort (95% CI, 25%-51%); the disease-specific survival adjusted by eye cancer center was better in patients who had received rituximab in addition to the chemotherapy regimen (hazard ratio, 3.3; 95% CI, 1.0-14.7; P = .06). The median progression-free survival was 2.3 years (95% CI, 1.8-2.7 years) in patients who experienced recurrence after primary treatment, and 4.1 years (95% CI, 3.9-4.3 years) in patients who presented with a relapse of systemic lymphoma in the ocular adnexal region.

Conclusions and Relevance

These results suggest that the distinctive features of OA-MCL are its appearance in older male individuals, advanced stage and bilateral manifestation at the time of diagnosis, and aggressive course. The prognosis of patients with OA-MCL might be improved by addition of rituximab to chemotherapy treatment.

An Update on Tumors of the Lacrimal Gland

Lacrimal gland tumors are rare and constitute a wide spectrum of different entities ranging from benign epithelial and lymphoid lesions to high-grade carcinomas, lymphomas, and sarcomas with large differences in prognosis and clinical management. The symptoms and findings of a lacrimal gland lesion are a growing mass at the site of the lacrimal gland, including displacement of the eyeball, decreased motility, diplopia, and ptosis. Pain is the cardinal symptom of an adenoid cystic carcinoma. Radiological findings characteristically include an oval, well-demarcated mass for benign lesions whereas malignant lesions typically display calcifications, destruction of bone, and invasion of adjacent structures. The diagnosis ultimately relies on histology, as does the choice of treatment and the prognosis. In recent years, the understanding of the biology of numerous types of lacrimal gland neoplasia has improved and the choice of treatment has changed accordingly and holds further promise for future targeted therapies. Treatment of benign epithelial lesions is surgical excision whereas carcinomas often require adjuvant radiotherapy and/or chemotherapy. In contrast, the cornerstone in management of lymphoid lesions is chemotherapy, often including a monoclonal antibody. This article presents an update on the clinical, radiological, histological, and molecular features, along with treatment strategies for tumors of the lacrimal gland.

Malignant lymphoma of the conjunctiva

Conjunctival lymphomas constitute 25% of all ocular adnexal lymphomas. The majority are B-cell non-Hodgkin lymphomas (NHLs) (98%), whereas conjunctival T-cell NHLs are rare (2%). The most frequent subtype of conjunctival B-cell lymphoma is extranodal marginal zone lymphoma (EMZL; 81%), followed by follicular lymphoma (8%), diffuse large B-cell lymphoma (3%), and mantle cell lymphoma (3%). Extranodal marginal zone lymphoma occurs slightly more often in women and, along with follicular lymphoma, presents late in the seventh decade of life, whereas diffuse large B-cell lymphoma and especially mantle cell lymphoma have a predilection for the male gender and typically present in the eighth decade. Extranodal marginal zone lymphoma and follicular lymphoma present most frequently in the forniceal and bulbar conjunctiva. Conjunctival diffuse large B-cell lymphoma, mantle cell lymphoma and T-cell NHLs are characterized by a short duration of symptoms before the first ophthalmologic consultation. External beam radiotherapy is the treatment of choice for extranodal marginal zone lymphoma and follicular lymphoma, whereas diffuse large B-cell lymphoma, mantle cell lymphoma, and T-cell NHLs are mainly treated with chemotherapy. Conjunctival T-cell NHLs are associated with a particularly poor prognosis, with 50% of patients having progression or recurrence during a 1-year follow-up period.

Diffuse large B-cell lymphoma and mantle cell lymphoma of the ocular adnexal region, and lymphoma of the lacrimal gland: an investigation of clinical and histopathological features

Diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) constitute two distinct subtypes of non-Hodgkin lymphoma (NHL) associated with considerable morbidity and mortality. Marked diversities with regard to molecular biology and clinical features are recognized in different subsets of the two lymphomas. Because these differences could be related to the location of the lymphoma, it is of interest to investigate the clinical and histopathological features of DLBCL and MCL involving the ocular adnexal region (i.e. the orbit, eyelids, conjunctiva, lacrimal gland and lacrimal sac). Similarly, the lacrimal gland is the only glandular structure within the orbit. Because the lacrimal gland represents an important part of the immunological system, it is of interest to investigate lymphomas involving this location with regard to clinical and histological characteristics.

PURPOSE

  To characterize the clinical and histopathological features of Danish patients with DLBCL of the ocular adnexal region between 1980 and 2009 and of Danish ocular adnexal MCL patients from 1980 to 2005. Furthermore, the aim of this PhD was to review all specimens from patients with lymphoma of the lacrimal gland in Denmark between 1975 and 2009 to determine the distribution of lymphoma subtypes of the lacrimal gland and to describe the clinicopathological features of these patients.

RESULTS

  A total of 34 patients with DLBCL and 21 with MCL of the ocular adnexal region were identified. Twenty-seven patients had lacrimal gland lymphoma, including four DLBCLs and three MCLs from studies I and II. Elderly patients predominated in all three groups, with median ages of 78, 75 and 69 years in the DLBCL, the MCL and the lacrimal gland lymphoma groups, respectively. MCL patients had a preponderance of males, whereas females prevailed among lacrimal gland lymphoma patients. The orbit was the most common site of involvement in DLBCL and MCL. Most DLBCL patients had unilateral involvement, while MCL patients had a high frequency of bilateral involvement. Similarly, localized lymphoma was relatively frequently seen in DLBCL patients in contrast to the predominance of disseminated lymphoma in the MCL group. The majority of lacrimal gland lymphomas were low grade, and the distribution of subtypes was as follows: extranodal marginal zone lymphoma, 10 (37%); follicular lymphoma, 5 (19%); DLBCL, 4 (15%); MCL, 3 (11%); chronic lymphocytic leukaemia/small lymphatic lymphoma, 2 (7%); and unclassified B-cell lymphoma, 3 (11%). The overall survival rates at 3 and 5 years for the entire study group of DLBCL were 42% and 20%, whereas 58% and 22% of MCL patients were alive 3 and 5 years after the time of diagnosis. The 5-year overall survival rate of lacrimal gland lymphoma patients was 70%. Concordant bone marrow involvement and the International Prognostic Index score were predictive factors for the overall survival in the DLBCL group in Cox regression analysis. Rituximab-containing chemotherapy was associated with an improved survival rate in MCL patients.

CONCLUSIONS

  Diffuse large B-cell lymphoma and MCL involving the ocular adnexal region and lymphoma of the lacrimal gland are prevalent among elderly patients. The overall prognosis in DLBCL and MCL was poor, whereas the prognosis for lacrimal gland lymphoma patients was relatively good. Concordant bone marrow involvement and the International Prognostic Index score were independent predictive factors for mortality in the DLBCL group. Chemotherapy containing rituximab significantly improved survival in the MCL group.

Cyclin D1 overexpression in N-methyl-N'-nitro-N-nitrosoguanidine-induced rat gastric adenocarcinomas

Changes in cell cycle regulation are involved in many human cancers, including gastric cancer. In the present study, cyclin D1 expression and localization were immunohistochemically analyzed in 23 N-methyl-N'-nitro-N-nitrosoguanidine-induced rat gastric adenocarcinomas and compared with findings for beta-catenin. Cyclin D1 nuclear overexpression was more frequently observed in tumors displaying nuclear (4/4=100%) and cytoplasmic (3/4=75%) beta-catenin accumulation than those with membranous (3/15=20%) localization (nuclear vs. membranous, P<0.02). In the former cases it was considered that cyclin D1 was induced with beta-catenin activation; in the latter, a direct or indirect pathway for cyclin D1 accumulation bypassing Wnt pathway might be involved. Cyclin D1 was also found to be accumulated in gastric glands within normal-looking mucosa, these perhaps representing preneoplastic lesions for cancers with membranous beta-catenin accumulation.

Derivative (14)t(11;14)(q13;q32)t(11;14)(p11.2;p11.2): a novel unbalanced variant of the t(11;14)(q13;q32) translocation in mantle cell lymphoma

We report the case of a 62-year-old man who presented with splenomegaly, leukocytosis, anemia, and thrombocytopenia. Examination of the peripheral blood, bone marrow, and spleen revealed involvement by mantle cell lymphoma, with some blastoid features and an atypical phenotype. Spleen and bone marrow classical chromosome analysis followed by fluorescence in situ hybridization revealed a novel and unusual unbalanced variant of the t(11;14)(q13;q32) translocation, resulting in a complex derivative chromosome harboring the IGH/CCND1 fusion gene. This chromosome was designated as der(14)t(11;14)(q13;q32)t(11;14)(p11.1;p11.2).

A low toxicity maintenance regime, using eicosapentaenoic acid and readily available drugs, for mantle cell lymphoma and other malignancies with excess cyclin D1 levels

Mantle cell lymphoma is a difficult to treat non-Hodgkin's lymphoma (NHL) whose biochemistry is unusually well characterised. Almost all and perhaps all patients overexpress the cyclin D1 protein which is crucial in driving cells from the G1 to the S phase. This overexpression may be responsible for the refractoriness. Despite this understanding, treatments for mantle cell lymphoma are based on standard NHL regimes of cyclophosphamide, doxorubicin, vincristine and prednisone, perhaps supplemented with the monoclonal antibody rituximab. There has never been any attempt to direct treatment to the cyclin D1 mechanism or to angiogenesis which is now known to be important in all lymphomas. Both these targets lend themselves to long-term maintenance regimes of relatively low toxicity which can be used as adjuvants to standard therapy. Agents which have recently been shown to block cyclin D1 translation by regulating calcium levels are the unsaturated essential fatty acid, eicosapentaenoic acid (EPA), the antidiabetic thiazolidinediones, and the antifungal agent, clotrimazole. Two types of agent which have been shown to inhibit angiogenesis are the teratogen, thalidomide, and the selective inhibitors of cyclo-oxygenase 2 (COX-2). Retinoids exert synergistic effects with EPA and have been shown to inhibit both tumour growth and angiogenesis. The mechanisms of action of these various agents are discussed, and specific suggestions are made for low toxicity maintenance therapy of mantle cell lymphoma and of other tumours which overexpress cyclin D1.

Molecular cytogenetic characterization of Sézary syndrome

Sézary syndrome (SS) is a rare form of erythrodermic cutaneous T-cell lymphoma with hematological involvement and a poor prognosis. At present little is known about the molecular pathogenesis of this malignancy. To address this issue, we analyzed 28 SS cases through the use of molecular cytogenetic techniques. Conventional cytogenetic analysis showed 12 of 28 cases with clonal chromosome abnormalities (43%). Seven cases had aberrations affecting chromosomes 1 and 17; five demonstrated rearrangement of chromosomes 10 and 14; four presented with an abnormality of 6q. Multiplex-fluorescence in situ hybridization (M-FISH) revealed complex karyotypes in 6 of 17 cases (35%), and recurrent der(1)t(1;10)(p2;q2) and der(14)t(14;15)(q;q?) translocations were each identified in two cases, and confirmed by dual-color FISH. There was an overall difference in the incidence of clonal abnormalities detected by G-banded karyotyping and M-FISH. In addition, comparative genomic hybridization studies revealed chromosome imbalances (CIs) in 9 of 20 cases (45%), with a mean DNA copy number change per sample of 1.95 +/- 2.74, and losses (mean: 1.25 +/- 1.77) more frequent than gains (mean: 0.7 +/- 1.26). The most common CIs noted were loss of 1p, followed by losses of 10/10q, 17p, and 19, and gains of 17q and 18. Furthermore, in conjunction with this study a systematic literature review was conducted, which showed a high frequency and consistent pattern of chromosome changes in SS. These findings suggest that chromosomal instability is common in SS, although there are specific chromosomal abnormalities that appear to be characteristic, and the identification of two different recurrent chromosome translocations provides the basis for further studies.

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.

Cyclin D1 by flow cytometry as a useful tool in the diagnosis of B-cell malignancies

The translocation (11;14)(q13;q32) and its molecular counterpart the BCL-1 rearrangement are features observed in mantle cell lymphoma (MCL) and less commonly in other B-cell disorders. This rearrangement leads to cyclin D1 overexpression, which may be the main pathogenic event in these tumours and is therefore recognised as a diagnostic marker. We developed a flow cytometry method to detect cyclin D1 overexpression using the monoclonal antibody (MoAb) 5D4, and characterised its frequency in 93 B-cell malignancies. The competitive reverse transcriptase polymerase chain reaction (RT-PCR) for cyclin D1, D2 and D3 was then performed on 40 of these cases to assess the validity of the flow cytometry method. Fluorescence in situ hybridisation (FISH) to detect t(11;14)(q13;q32) was carried out on 31 cases and results were compared with cyclin D1 expression by flow cytometry. Twenty five cases showed cyclin D1 expression using 5D4, including MCL (12/13, 92%), chronic lymphocytic leukaemia (CLL) (4/30), B-prolymphocytic leukaemia (B-PLL) (1/4), splenic lymphoma with villous lymphocytes (SLVL) (4/13), hairy cell leukaemia (HCL) (1/7) and other B-non Hodgkins Lymphoma (B-NHL) (3/15). There was a good correlation between flow cytometry results and RT-PCR in 36/40 cases (90%), and with FISH for t(11;14) in 25/31 cases (80%). We concluded that the detection of cyclin D1 expression by flow cytometry in cell suspensions could be applied routinely to the study of B-lymphoproliferative disorders and may be of value for their diagnosis and management.

Primary Hyperparathyroidism and Lymphoproliferative Diseases: Three Case Reports

Pathophysiologic mechanisms of malignancy-associated hypercalcemia are varied. The association of neoplasia and primary hyperparathyroidism (PHP) has been illustrated by clinical cases and by epidemiologic studies which have pointed to an increased risk of different malignancies during PHP. The authors report two cases of monoclonal gammapathy and one case of chronic lymphocytic leukemia (CLL) associated with PHP. A 58-year-old man presented with hypercalcemia due to PHP after remission for multiple plasmacytoma was obtained. A 70-year-old man was hospitalized for malaise, studies showed major hypercalcemia and benign monoclonal gammapathy. In the two cases, resolution of hypercalcemia was obtained by parathyroidectomy. The third patient was a 84-year-old woman with CLL who continued to deteriorate despite response to therapy, further studies confirmed hyperparathyroidism Physiopathogenic mechanisms of this association are discussed. The PHP-malignancy association should be considered ifthe symptoms or outcome of anyone of the two diseases are atypic.

Evidence for a direct correlation between c-Jun NH2 terminal kinase 1 activation, cyclin D2 expression, and G(1)/S phase transition in the murine hybridoma 7TD1 cells

In this study we show that the addition of fresh culture medium to high-density growth-arrested 7TD1 cells induces a strong and transient stimulation of the c-Jun NH2 terminal kinase activity (Jun kinase/JNK), a marked increase in cyclin D2 expression, the phosphorylation of pRb, and the transition from G(1) to S phase. The stimulation of cyclin D2 expression and the induction of JNK activity appear to be the consequences of the alkalinization of the extracellular medium. Indeed both parameters (i) can be induced, regardless of cell dilution, by the addition of a weak base such as triethylamine, and (ii) are together inhibited by (N-ethyl-N-isopropyl)amiloride, a specific inhibitor of the Na(+)/H(+) exchanger. We provide a strong argument indicating the existence of a direct correlation between JNK1 activation and cyclin D2 stimulation. Indeed, we demonstrate that cyclin D2 expression is blocked by SB 202190, an agent known to inhibit both JNK and p38(MAPK), but not by SB 203580, a specific inhibitor of p38(MAPK). Furthermore, we also observed that DMSO and forskolin, two agents that inhibit the proliferation of 7TD1 cells, inhibit in parallel cyclin D2 and JNK1. Altogether our results suggest that (i) JNK1 participates in the signaling pathway which controls the expression of cyclin D2 and (ii) that the inhibition of JNK1 by DMSO and forskolin could explain, at least in part, the antiproliferative action of these drugs in 7TD1 cells.

Transcriptional and post-transcriptional mechanisms induce cyclin-D1 over-expression in B-chronic lymphoproliferative disorders

Cyclin D1 participates in cell-cycle control, in the progression through the G(1) phase and in the transition from the G(1) to the S phase. The CCND1 locus, located in 11q13, is amplified and cyclin-D1 protein is over-expressed in a wide range of human solid tumors. In some B-lymphoid malignancies, the t(11;14)(q13;q32) translocation joins the Ig heavy-chain locus to the CCND1 locus and leads to cyclin-D1 over-expression. In this study, a series of 127 patients presenting a B-chronic lymphoproliferative disorder (B-CLPD) was analyzed using a competitive RT-PCR designed to detect cyclin-D1-mRNA over-expression. Cyclin-D1 mRNA was expressed in patients with mantle-cell lymphoma (MCL; 10/10), hairy-cell leukemia (HCL; 3/5), B-chronic lymphoid leukemia (B-CLL; 4/111) and B large-cell lymphoma (BLCL; 1/1). Densitometric analysis of RT-PCR products and Western-blot autoradiograms, in addition to cytogenetic data, indicated that activation of the cyclin-D1 gene occurred independently of the t(11;14)(q13;q32) translocation in patients with HCL. Indeed, a normal-sized protein of 36 kDa exhibiting a level incompatible with gene activation by a translocation mechanism was detected in lymphoid cells with a normal karyotype. Moreover, we found a discrepancy between cyclin-D1 mRNA and protein levels in MCL and B-CLL, which suggested that some regulatory mechanisms acting at a post-transcriptional level persist in tumor cells.

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 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.