A comparative analysis of FISH, RT-PCR, PCR, and immunohistochemistry for the diagnosis of mantle cell lymphomas

An alternative method for SARS-CoV-2 detection with use modified fluorescent in situ hybridization

The real-time reverse-transcriptase polymerase-chain-reaction (rRT-PCR) tests are the gold standard in detecting SARS-CoV-2 virus infection. However, despite high sensitivity and specificity, they have limitations that in some cases may result in false negative results. Therefore, it is reasonable to search for additional tools that could support microbiological diagnosis of SARS-CoV-2. The aim of the study was to develop a highly specific molecular test capable of detecting and visualizing SARS-CoV-2 infection. A universal probe and a set of 18 specific oligonucleotides with a FLAP sequence attached to them on both sides were designed to visualize SARS-CoV-2 virus infection based on the fluorescence in situ hybridization method (FISH). FISH conditions using the developed kit were standardized on the Vero CCL-81 cell line infected by SARS-CoV-2 virus. The method was tested on 290 nasopharyngeal swabs (collected in a doublet) from patients with clinical symptoms of SARS-CoV-2. Each one swab from the doublet was subjected to RNA isolation and amplification by rRT-PCR. From the second swab, a microscopic preparation was performed for FISH. The use of the rRT-PCR allowed obtaining 200 positive and 90 negative results, while our FISH method allowed for 220 positive results and 70 negative results. The differences obtained using both methods were statistically significant (p = 0.008). The obtained results support the use of FISH as an additional method in microbiological diagnostics of SARS-CoV-2.

Imprint cytology: Invaluable technique to evaluate fresh specimens received in the pathology department for Lymphoma workup

At the time of intraoperative consultation, cytologic preparations including smears and imprints can be used in combination with frozen sections to increase diagnostic yield; however, these simple and rapid techniques are not adopted by all pathologists and their use varies considerably between institutions. In patients under investigation for suspected lymphoma, optimal triaging of tissue received fresh in pathology for lymphoma workup is paramount to maximize the odds of obtaining an accurate and clinically meaningful diagnosis and to avoid the need for additional procedures and delays in management, particularly in the current context in which core biopsies have become common practice as a first attempt to attain this goal. Imprint cytology is invaluable in this regard, also as these patients may not have a lymphoma but rather one of its clinical mimics. Herein, imprint cytology is used to approach fresh specimens received intraoperatively for lymphoma workup. More specifically, how these specimens are triaged for ancillary studies, such as flow cytometry, florescence in situ hybridization, or molecular analyses based on an interpretation of the touch imprints, is described. Detailed imprint cytological findings of typical benign and malignant lymphoid and nonlymphoid lesions are discussed and illustrated.

Monitoring clinical outcomes in aggressive B-cell lymphoma: From imaging studies to circulating tumor DNA

Recent guidelines have de-emphasized the role of routine surveillance computed tomography (CT) scans for diffuse large B-cell lymphoma (DLBCL) patients who achieve a complete response to front-line therapy. This shift in practice recommendations was prompted by retrospective studies that failed to demonstrate clear clinical utility for surveillance CT in unselected DLBCL patients. Controversy remains, however, over the role of routine surveillance CT in the highest risk patients for treatment failure who would remain candidates for aggressive salvage therapies. Novel high-throughput sequencing methods can non-invasively monitor tumor-specific DNA in the blood and offers clear advantages designed to overcome fundamental limitations of CT scans. This review will discuss the current controversies surrounding monitoring clinical outcomes in aggressive B-cell lymphomas, with a specific emphasis on DLBCL. Fundamental limitations of imaging scans will be addressed and the potential of monitoring circulating tumor DNA as an adjunct or replacement for CT scans will be discussed.

Relationship between expression of vascular endothelial growth factor and intratumoral hemorrhage in human pituitary adenomas

Aims and background

Although pituitary adenoma is a primary brain tumor that occasionally accompanies intratumoral hemorrhage, there are little reports about the molecular mechanism of intratumoral bleeding in pituitary adenoma. Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis and vascular permeability of various brain tumors. The authors studied the relationship between intratumoral hemorrhage and the expression of VEGF in human pituitary adenomas.

Methods

VEGF expression was assessed by reverse transcriptase polymerase chain reaction (RT-PCR) in 71 pituitary adenomas. Clinical factors to investigate were age, gender, hormonal functioning, and radiological findings of pituitary adenomas. Radiological findings which were investigated by magnetic resonance (MR) images were intratumoral hemorrhage, cystic change, tumor size, and cavernous sinus invasion. The relationship between these factors and VEGF expression was statistically analyzed.

Results

VEGF was expressed in 25 cases (35.2%). Functioning tumors, hemorrhage, cystic change, and cavernous sinus invasion were 32 (45.1%), 18 (25.4%), 12 (16.9%), and 21 (29.6%) respectively. The expression of VEGF showed a significant relationship with the intratumoral hemorrhage of the adenomas (P <0.001). However, age, gender, tumor size, hormonal functioning, cyst formation, and cavernous sinus invasion had no relationship with VEGF expression (P >0.05).

Conclusions

This study suggests that VEGF expression may be responsible for intratumoral hemorrhage of pituitary adenomas. Therefore, VEGF can be a novel target to prevent a catastrophic apoplexy in pituitary adenomas and to establish roles in angiogenesis-based therapeutics of pituitary adenomas.

Cyclin D1 expression by histiocytes may mimic cyclin D1-positive proliferation centres of chronic lymphocytic leukaemia/small lymphocytic lymphoma

AIMS

Cyclin D1, generally considered to be absent in chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL), has been reported in the proliferation centres (PCs) of recent CLL/SLL cases. Cyclin D1 immunostaining in CLL/SLL may lead to diagnostic confusion. The objective of this study was to identify the types of stained cells and the impact on diagnosis.

METHODS

Cyclin D1 expression was assessed by immunostaining samples from 46 cases of CLL/SLL. CD68 and double immunostaining with CD20/CyclinD1, CD68/CyclinD1, and CD163/CyclinD1 were then performed in cases of CLL/SLL positive for cyclinD1 in the PCs.

RESULTS

Dim-positive cyclin D1 staining in randomly scattered cells in the CLL/SLLs were observed in 38/46 cases (82.6%). In five (10.9%) cases, more than 50 cyclin D1-positive cells per high-power field were detected within the PCs in CLL/SLL with weak to moderate intensity. Double immunochemical staining in these cases showed that cyclin D1 in these positive cells was mostly co-expressed with CD68 and CD163 and the cells were negative for CD20.

CONCLUSIONS

The cyclin D1-positive CLL/SLL cells in this study were mostly histiocytes. The expression of cyclin D1 by histiocytes may mimic cyclin D1+ CLL/SLL; thus, the recognition of cyclin D1 expression by non-lymphoid cells in lymphoma is important.

Clear cell renal cell carcinoma: a comparative study of histological and chromosomal characteristics between primary tumors and their corresponding metastases

Clear cell renal cell carcinoma (ccRCC) has a poor prognosis with a 50% risk of metastases. Little is known about the phenotypic and molecular profiles of metastases regarding their corresponding primary tumors. This study aimed to screen phenotypic and genotypic differences between metastases and their corresponding primary tumors. We selected four cases with available frozen material. The histological, immunohistochemical (VEGFA, CD31, SMA, Ki67, p53, PAR-3), FISH (VHL gene), next-generation sequencing (VHL and c-MET genes), multiplex ligation-dependent probe amplification, and array-(comparative genomic hybridization) CGH analyses were realized. Metastases were nodal, hepatic (synchronous), adrenal, and pulmonary (metachronous). High-grade tumor cells were significantly more frequent in metastases (p = 0.019). Metastases and high-grade zones of primary tumors shared similar characteristics compared to low-grade zones: a lower microscopic vascular density (43.5 vs 382.5 vessels/mm²; p = 0.0027), a higher expression of VEGF (73 vs 10%, p = 0.045), Ki67 (37.6 vs 8.3%; p = 0.011), and p53 (54 vs 10.6%; p = 0.081), and a cytoplasmic and membranous PAR-3 staining. Metastases exhibited more chromosomal imbalances than primary tumors in total (18.75 ± 6.8; p = 0.044) with more genomic gains (13.5 ± 7; p = 0.013). The loss of chromosome 9 and gain of Xq were found in both primary tumors and metastases but gains of loci or chromosomes 2p, 3q, 5, 8q, 12, and 20 were only found in metastases. The VHL gene status was similar in each tumor couple. Although metastases and primary tumors share common histological features, this study highlights chromosomal differences specific to metastases which could be involved in ccRCC metastatic evolution.

Persistence of a t(11;14)-positive clone in a patient with mantle cell lymphoma for 20 years

We report here a patient with extremely indolent mantle cell lymphoma (MCL) who had progressed and required immunochemotherapy 20 years after diagnostic splenectomy. Non‐nodal, indolent MCL patients may progress after such an extraordinary long indolent phase, and we recommend lifelong follow up for such cases.

Mantle Cell Lymphoma: Contemporary Diagnostic and Treatment Perspectives in the Age of Personalized Medicine

Mantle cell lymphoma is a clinically heterogeneous disease occurring within a heterogeneous patient population, highlighting a need for personalized therapy to ensure optimal outcomes. It is therefore critical to understand the benefits and risks associated with both intensive and deintensified approaches. In the following review we provide a therapeutic roadmap to strategically guide treatment for newly diagnosed and relapsed/refractory patients highlighting pivotal and recently published results involving known and novel therapies.

Dual CD19 and CD123 targeting prevents antigen-loss relapses after CD19-directed immunotherapies

Potent CD19-directed immunotherapies, such as chimeric antigen receptor T cells (CART) and blinatumomab, have drastically changed the outcome of patients with relapsed/refractory B cell acute lymphoblastic leukemia (B-ALL). However, CD19-negative relapses have emerged as a major problem that is observed in approximately 30% of treated patients. Developing approaches to preventing and treating antigen-loss escapes would therefore represent a vertical advance in the field. Here, we found that in primary patient samples, the IL-3 receptor α chain CD123 was highly expressed on leukemia-initiating cells and CD19-negative blasts in bulk B-ALL at baseline and at relapse after CART19 administration. Using intravital imaging in an antigen-loss CD19-negative relapse xenograft model, we determined that CART123, but not CART19, recognized leukemic blasts, established protracted synapses, and eradicated CD19-negative leukemia, leading to prolonged survival. Furthermore, combining CART19 and CART123 prevented antigen-loss relapses in xenograft models. Finally, we devised a dual CAR-expressing construct that combined CD19- and CD123-mediated T cell activation and demonstrated that it provides superior in vivo activity against B-ALL compared with single-expressing CART or pooled combination CART. In conclusion, these findings indicate that targeting CD19 and CD123 on leukemic blasts represents an effective strategy for treating and preventing antigen-loss relapses occurring after CD19-directed therapies.

Ibrutinib-associated tumor lysis syndrome in a patient with mantle cell lymphoma: A case report

Mantle cell lymphoma accounts for 5-7% of all non-Hodgkin's lymphomas. Under the current WHO classification, it is categorized as an indolent B cell lymphoma, but has an aggressive clinical course. New insights into leukemogenic molecular pathways of mantle cell lymphoma have uncovered unique therapeutic targets. Ibrutinib, a Bruton's tyrosine kinase inhibitor, is the newest drug in the arsenal that has shown promising efficacy in relapsed mantle cell lymphoma. Long-term studies have shown that grade 3 or 4 adverse events are infrequent. Asymptomatic lymphocytosis is frequently seen with ibrutinib use in mantle cell lymphoma; however, tumor lysis syndrome is an extremely rare complication. To date, only two patients with ibrutinib-associated tumor lysis syndrome in mantle cell lymphoma have been described in a long-term follow-up study. Both patients met laboratory criteria for tumor lysis syndrome, however, but did not develop clinical tumor lysis syndrome. We, here describe a patient with relapsed mantle cell lymphoma who developed clinical tumor lysis syndrome with ibrutinib monotherapy.

Diagnostic utility of SOX11 immunohistochemistry in differentiating cutaneous spread of mantle cell lymphoma from primary cutaneous B-cell lymphomas

BACKGROUND

Mantle cell lymphoma (MCL) is associated with the worst prognosis among low-grade B-cell lymphomas. While cutaneous involvement by nodal or systemic MCL is uncommon, its differentiation from primary cutaneous B-cell lymphoma (CBCL) or cutaneous involvement by other extra-cutaneous BCL is challenging as neither histomorphology nor immunophenotype can be absolutely specific. We analyzed the diagnostic utility of SOX11 immunohistochemistry in differentiating secondary cutaneous MCL from other low-grade CBCL.

METHODS

Immunohistochemical staining with anti-SOX11 antibody was performed on 8 cases of secondary cutaneous MCL, 16 secondary cutaneous CLL, 20 primary cutaneous MZL, 12 cutaneous FCL (6 primary, 6 secondary), 7 primary cutaneous DLBCL, leg type, 5 systemic DLBCL and 3 B-ALL. SOX11 and cyclin D1 staining were compared in secondary cutaneous MCL.

RESULTS

Nuclear SOX11 staining was seen in seven of eight cases (88%) of secondary cutaneous MCL, including a case with minimal cyclin D1 expression. All other CBCL lacked detectable nuclear SOX11 expression. The sensitivity and specificity for SOX11 in MCL were 87.5 and 100%, respectively. Both the sensitivity and specificity for combined SOX11 and cyclin D1 immunohistochemistry were 100%.

CONCLUSION

SOX11 immunohistochemistry could be a useful adjunct in distinguishing secondary cutaneous MCL from other CBCL.

The Addition of the BTK Inhibitor Ibrutinib to Anti-CD19 Chimeric Antigen Receptor T Cells (CART19) Improves Responses against Mantle Cell Lymphoma

PURPOSE

Responses to therapy with chimeric antigen receptor T cells recognizing CD19 (CART19, CTL019) may vary by histology. Mantle cell lymphoma (MCL) represents a B-cell malignancy that remains incurable despite novel therapies such as the BTK inhibitor ibrutinib, and where data from CTL019 therapy are scant. Using MCL as a model, we sought to build upon the outcomes from CTL019 and from ibrutinib therapy by combining these in a rational manner.

EXPERIMENTAL DESIGN

MCL cell lines and primary MCL samples were combined with autologous or normal donor-derived anti-CD19 CAR T cells along with ibrutinib. The effect of the combination was studied in vitro and in mouse xenograft models.

RESULTS

MCL cells strongly activated multiple CTL019 effector functions, and MCL killing by CTL019 was further enhanced in the presence of ibrutinib. In a xenograft MCL model, we showed superior disease control in the CTL019- as compared with ibrutinib-treated mice (median survival not reached vs. 95 days, P < 0.005) but most mice receiving CTL019 monotherapy eventually relapsed. Therefore, we added ibrutinib to CTL019 and showed that 80% to 100% of mice in the CTL019 + ibrutinib arm and 0% to 20% of mice in the CTL019 arm, respectively, remained in long-term remission (P < 0.05).

CONCLUSIONS

Combining CTL019 with ibrutinib represents a rational way to incorporate two of the most recent therapies in MCL. Our findings pave the way to a two-pronged therapeutic strategy in patients with MCL and other types of B-cell lymphoma. Clin Cancer Res; 22(11); 2684-96. ©2016 AACR.

BreaKmer: detection of structural variation in targeted massively parallel sequencing data using kmers

Genomic structural variation (SV), a common hallmark of cancer, has important predictive and therapeutic implications. However, accurately detecting SV using high-throughput sequencing data remains challenging, especially for ‘targeted’ resequencing efforts. This is critically important in the clinical setting where targeted resequencing is frequently being applied to rapidly assess clinically actionable mutations in tumor biopsies in a cost-effective manner. We present BreaKmer, a novel approach that uses a ‘kmer’ strategy to assemble misaligned sequence reads for predicting insertions, deletions, inversions, tandem duplications and translocations at base-pair resolution in targeted resequencing data. Variants are predicted by realigning an assembled consensus sequence created from sequence reads that were abnormally aligned to the reference genome. Using targeted resequencing data from tumor specimens with orthogonally validated SV, non-tumor samples and whole-genome sequencing data, BreaKmer had a 97.4% overall sensitivity for known events and predicted 17 positively validated, novel variants. Relative to four publically available algorithms, BreaKmer detected SV with increased sensitivity and limited calls in non-tumor samples, key features for variant analysis of tumor specimens in both the clinical and research settings.

Role of molecular studies in the classification of lymphoma

The classification of lymphomas has historically lacked both precision and accuracy, potentially compromising both optimal diagnosis and therapy. The genetic characterization of key oncogenic events and the advent of expression profiling have afforded the opportunity to understand, diagnose and treat these diseases in a much more rational and targeted manner. As exciting as these new and testable data are, it is also worth noting that molecular genetic analysis of the tumor in isolation will not be the sole arbiter of patient outcome. It is likely that we will remain reliant on traditional and sometimes subjective technologies, albeit probably to a lesser degree, with molecular studies significantly complementing, but certainly not replacing, microscopic, immunophenotypic and cytogenetic approaches. Furthermore, we will perhaps need to extend genotyping to the tumor milieu (the patient) in order to molecularly dissect drug metabolic pathways and the immune response.

Dietary restriction in the periconceptional period in normal-weight or obese ewes results in increased abundance of angiotensin-converting enzyme (ACE) and angiotensin type 1 receptor (AT1R) in the absence of changes in ACE or AT1R methylation in the adrenal of the offspring

Exposure to dietary restriction during the periconceptional period in either normal or obese ewes results in increased adrenal growth and a greater cortisol response to stress in the offspring, but the mechanisms that programme these changes are not fully understood. Activation of the angiotensin type 1 receptor (AT1R) has been demonstrated to stimulate adrenal growth and steroidogenesis. We have used an embryo transfer model in the sheep to investigate the effects of exposure to dietary restriction in normal or obese mothers from before and 1 week after conception on the methylation status, expression, abundance and localisation of key components of the renin–angiotensin system (RAS) in the adrenal of post-natal lambs. Maternal dietary restriction in normal or obese ewes during the periconceptional period resulted in an increase in angiotensin-converting enzyme (ACE) and AT1R abundance in the absence of changes in the methylation status or mRNA expression ofACEandAT1Rin the adrenal of the offspring. Exposure to maternal obesity alone also resulted in an increase in adrenal AT1R abundance. There was no effect of maternal dietary restriction or obesity on ACE2 and AT2R or on ERK, calcium/calmodulin-dependent kinase II abundance, and their phosphorylated forms in the lamb adrenal. Thus, weight loss around the time of conception, in both normal-weight and obese ewes, results in changes within the intra-adrenal RAS consistent with increased AT1R activation. These changes within the intra-adrenal RAS system may contribute to the greater adrenal stress response following exposure to signals of adversity in the periconceptional period.

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

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

Nucleic acid amplification using microfluidic systems

In the post-human-genome-project era, the development of molecular diagnostic techniques has advanced the frontiers of biomedical research. Nucleic-acid-based technology (NAT) plays an especially important role in molecular diagnosis. However, most research and clinical protocols still rely on the manual analysis of individual samples by skilled technicians which is a time-consuming and labor-intensive process. Recently, with advances in microfluidic designs, integrated micro total-analysis-systems have emerged to overcome the limitations of traditional detection assays. These microfluidic systems have the capability to rapidly perform experiments in parallel and with a high-throughput which allows a NAT analysis to be completed in a few hours or even a few minutes. These features have a significant beneficial influence on many aspects of traditional biological or biochemical research and this new technology is promising for improving molecular diagnosis. Thus, in the foreseeable future, microfluidic systems developed for molecular diagnosis using NAT will become an important tool in clinical diagnosis. One of the critical issues for NAT is nucleic acid amplification. In this review article, recent advances in nucleic acid amplification techniques using microfluidic systems will be reviewed. Different approaches for fast amplification of nucleic acids for molecular diagnosis will be highlighted.

Detection of genetic translocations in lymphoma using fluorescence in situ hybridization

Certain lymphoma types are characterized by recurring genetic translocations. Detection of these translocations enables confirmation of a suspected diagnosis and provides a genetic marker which can be subsequently monitored and followed. Rapid and reliable identification of these molecular rearrangements is a key component in the workup of lymphoma. While conventional cytogenetics may be a useful tool in this regard, fluorescence in situ hybridization (FISH) offers additional advantages including the ability to use formalin-fixed tissues, no requirement for dividing cells, ability to score many cells, improved sensitivity, and faster turnaround time for results.

Transformation of indolent mantle cell lymphoma to pleomorphic mantle cell lymphoma: case report and review of clinical and morphologic variants

We report a case of indolent mantle cell lymphoma with progression to pleomorphic mantle cell lymphoma 8 years after initial presentation. The first lymph node biopsy showed expanded mantle zones composed of uniformly small B lymphocytes. A cyclin D1 immunohistochemical stain was negative and the patient was observed. Eight years later, the patient developed symptomatic splenomegaly. Microscopic examination of the spleen revealed expanded mantle zones with an increased number of large cells with irregular nuclear contours. Immunohistochemistry for cyclin D1 was positive. A repeat cyclin D1 immunohistochemical staining performed on the initial lymph node biopsy was positive, indicating an inadequate initial study. Immunoglobulin heavy-chain gene rearrangement studies confirmed clonal identity. A revised diagnosis of indolent mantle cell lymphoma with progression to pleomorphic mantle cell lymphoma was rendered. The differential diagnosis of mantle cell lymphoma, including clinical and morphologic variants, is discussed.

Mantle cell lymphoma: a clinically heterogeneous disease in need of tailored approaches

BACKGROUND

Mantle cell lymphoma (MCL) remains incurable using conventional chemotherapeutic approaches. New clinical data show that some patients have a chronic/indolent course and others have a more fulminant course and short survival, similar to that of patients with acute leukemias.

METHODS

This review presents an overview of this aggressive disease, including the diagnosis, epidemiology, prognosis, and management of this protean and challenging condition.

RESULTS

Distinguishing indolent MCL from in situ MCL is important but can be challenging. Molecular exploration has identified SOX11 and HDAC11 as potential candidate genes for discrimination of indolent cases. Improvements in the prognosis in MCL are likely the result of earlier identification of more indolent cases and the application of modern modalities, including rituximab and autologous transplantation. Younger patients may be able to tolerate more intensive therapy, while treatment for elderly or frail patients may focus on maintenance to prolong remission. For patients with relapsed disease, some agents have shown promise, such as lenalidomide and bortezomib. Emerging drugs such as PCI37625 and CAL-101 are being explored in phase I and II studies.

CONCLUSIONS

Although patients with MCL continue to experience poor outcomes, new treatment approaches for various stages of disease are showing promise in improving survival.

Functions and uses of immunohistochemical stains in cutaneous infiltrates of hematopoietic origin: a review for the practicing dermatologist

BACKGROUND

Immunohistochemical stains, particularly those for cutaneous lymphomas, have similar-sounding names, which may lead to confusion among dermatologists who are not well versed in the terminology of the tools used for pathologic diagnosis. Also aiding in this is the fact that some familiar stains are constantly investigated for novel utility in different tumors, and a plethora of new stains regularly emerge in the peer-reviewed literature.

OBJECTIVE

To review the major stains encountered in dermatopathologic reports for cutaneous lymphomas. A select number of other stains are reviewed that are either new and under investigation in several cutaneous processes or have a new use described in recent reports.

METHODS

The peer-reviewed literature was searched and analyzed for the accepted purposes of using these markers.

RESULTS

All pertinent findings for these immunostains are reported with the purpose of educating the dermatology community.

CONCLUSION

This review serves as a reference to clarify potentially confusing immunohistochemical stains.

Nuclei micro-array FISH, a desirable alternative for MCL diagnosis

Mantle cell lymphoma (MCL) is a rare, specific lymphoma subtype. Though the morphologic and immunophenotypic features of MCL have been well described in recent literatures, it is still a diagnostic dilemma because of its frequent confusion with other small B cell lymphomas (SBCLs). In the present study, we primarily focus on establishing a sensitive and specific method for the diagnosis of MCL, which is efficient to distinguish this disease from other SBCLs. We carried out our investigation for MCL and other SBCLs (including SLL, FL, MZL, and MALT) on their feature of morphology, immunophenotype, and t(11;14)(q13;q32) translocation analysis based on polymerase chain reaction (PCR) and interphase nuclei micro-array fluorescence in situ hybridization (FISH). The morphologic and immunologic analysis showed the positive rate of cyclin D1 was 76.47% in MCL, which was significantly higher than that in other SBCLs. The positive rate of t(11;14) translocation was 25.81% and 35.48%, respectively, tested by general and semi-nested PCR, while 93.10% positive rate was shown with low background and strong signals pattern when tested by Nuclei micro-array FISH. Our research shows that t(11;14) translocation is a special and useful diagnostic marker for MCL, and detection of the marker by nuclei micro-array FISH is convenient and economic, especially more sensitive and specific than other methods for the diagnosis of MCL.

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

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

Molecular diagnosis of hematopoietic and lymphoid neoplasms

This chapter summarizes the significance and molecular diagnostic detection of genetic abnormalities commonly associated with hematolymphoid neoplasms. Methodologic aspects of laboratory diagnosis are presented, as well as discussion of multiparameter genotyping of tumors for prognosis and the role of minimal residual disease monitoring in specific neoplasms.

Characterization of genetic changes in MCL by interphase FISH on tissue sections

Mantle cell lymphoma is a clinically heterogeneous disease, where further elucidation of pathogenetic mechanisms and better prognostic information is required. We evaluated genetic aberrations by interphase FISH on tissue sections or cytological material in 38 samples from 30 MCL patients, including 5 cases with cyclin D1 3'UTR low, which previously has been associated to unfavourable prognosis. The findings have been related to proliferation and clinical outcome. All but one of MCL showed t(11:14) translocation and in 22/30 samples taken at diagnosis or first relapse, one or several cytogenetic changes were detected; 11 deletions of ATM, 13 p53 deletions, 8 numerical c-myc-aberrations and 6 delp16. All but one MCL with low cyclin D1 3'UTR had additional cytogenetic changes, however no particular genetic change was strictly associated with this MCL variant. One fourth of MCL had none of the investigated additional aberrations and these tumours were in general less proliferative and some of these patients had a very long survival.

Usefulness of long-distance inverse polymerase chain reaction for molecular detection of 14q32 translocation in a clinical setting

All mature B-cell leukaemias and lymphomas have a clonal Ig gene recombination, and half of them have a reciprocal chromosomal translocation involving the 14q32 locus. The 14q32 translocation partners are variable, such as BCL-2, BCL-1 and BCL-6, thus accounting for the difficulty in molecular detection by the current genomic polymerase chain reaction (PCR) method. To identify B-cell clones efficiently with an Ig gene rearrangement and reciprocal inter-chromosomal translocation, we verified the usefulness, in a practical laboratory setting, of our modified long-distance inverse (LDI) PCR method for detecting IgH gene rearrangements involving inter- and intra-chromosomal segments. The total run time of this LDI PCR method was 5.5 h. Using 24 samples of mature B-cell leukaemias and lymphomas, the modified LDI PCR gave clonally rearranged amplicons in 83 % (20/24) of cases. Direct sequencing results of the amplicons revealed inter-chromosomal translocations in 5 cases (25 %) and intra-chromosomal rearrangements in the remaining 15 cases (75 %). The partners of the inter-chromosomal translocation consisted of the 11q13.3 segment containing a partial BCL1 sequence in 3 cases; 18q21.3 segment containing a partial BCL2 sequence in one case; and a segment of 7ql1.2 in one case. We present an LDI PCR-based methodology for the efficient identification of 14q32 translocations, with modifications to reduce the total run time to within one day.

Small B-cell neoplasms with typical mantle cell lymphoma immunophenotypes often include chronic lymphocytic leukemias

Mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) are CD5+ small B-cell neoplasms (SBCNs) with overlapping features. Flow cytometric immunophenotyping is often used to help differentiate CLL from MCL, and a characteristic CLL phenotype is considered essentially diagnostic. However, previous studies have not specifically examined how well a typical MCL immunophenotype distinguishes MCL from CLL. We identified 28 cases of SBCN with typical flow cytometry-determined MCL immunophenotypes consisting mostly of peripheral blood and bone marrow specimens. Fluorescence in situ hybridization analysis indicated that 57% (16/28) had t(11;14) translocations consistent with MCL, while 32% (9/28) lacked t(11;14) translocations but harbored other cytogenetic abnormalities commonly found in CLL. There were no significant morphologic or immunophenotypic differences between the t(11;14)-positive and t(11;14)-negative cases. Our findings suggest that many blood-based SBCNs with typical MCL immunophenotypes likely represent cases of phenotypically atypical CLL, which would have important clinical implications.

Translocation detection in lymphoma diagnosis by split-signal FISH: a standardised approach

Lymphomas originating from the lymphatic system comprise about 30 entities classified according to the World Health Organization (WHO). The histopathological diagnosis is generally considered difficult and prone to mistakes. Since non-random chromosomal translocations are specifically involved in different lymphoma entities, their detection will be increasingly important. Hence, a split-signal fluorescence in situ hybridisation (FISH) procedure would be helpful in discriminating the most difficult classifications. The Euro-FISH programme, a concerted action of nine European laboratories, has validated a robust, standardised protocol to improve the diagnostic approach on lymphoma entities. Therefore, 16 fluorescent probes and 10 WHO entities, supplemented with reactive cases, were selected. The results of the Euro-FISH programme show that all probes were correctly cytogenetically located, that the standardised protocol is robust, resulting in reliable results in approximately 90% of cases, and that the procedure could be implemented in every laboratory, bringing the relatively easy interpretation of split-signal probes within the reach of many pathology laboratories.

Application of Immunohistochemistry in the Diagnosis of Non-Hodgkin and Hodgkin Lymphoma

Context.—Beginning with the immunologic classifications of Lukes and Collins and Kiel and culminating in the Revised European-American Lymphoma and World Health Organization classifications, the diagnosis of lymphoid tumors relies heavily on the determination of cell lineage, maturation, and function, based on antigen expression in addition to morphology and clinical features. Technologic advances in immunology, antibody production, genetic analysis, cloning, and the identification of new genes and proteins by microarray and proteomics have provided pathologists with many antibodies to use in routine diagnosis.

Objective.—To provide guidance to the practicing pathologist in the appropriate selection of an antibody panel for the diagnosis of lymphoma based on morphology and relevant clinical data and to avoid pitfalls in the interpretation of immunohistochemical data. Attention is given to some of the newer antibodies, particularly against transcription factors, that are diagnostically and prognostically useful.

Data Sources.—The information presented in this article is based on review of the literature using the OVID database (Ovid MEDLINE 1950 to present with daily update) and 20 years of experience in diagnostic hematopathology.

Conclusions.—Immunophenotyping is required for the diagnosis and classification of lymphoid malignancies. Many paraffin-reactive antibodies are available to the pathologist but most are not specific. To avoid diagnostic pitfalls, interpretation of marker studies must be based on a panel and knowledge of a particular antigen's expression in normal, reactive, and neoplastic conditions.

Molecular genetic analysis of haematological malignancies II: mature lymphoid neoplasms

Molecular genetic techniques have become an integral part of the diagnostic assessment for many lymphomas and other chronic lymphoid neoplasms. The demonstration of a clonal immunoglobulin or T cell receptor gene rearrangement offers a useful diagnostic tool in cases where the diagnosis is equivocal. Molecular genetic detection of other genomic rearrangements may not only assist with the diagnosis but can also provide important prognostic information. Many of these rearrangements can act as molecular markers for the detection of low levels of residual disease. In this review, we discuss the applications of molecular genetic analysis to the chronic lymphoid malignancies. The review concentrates on those disorders for which molecular genetic analysis can offer diagnostic and/or prognostic information.

CD5-positive mucosa-associated lymphoid tissue (MALT) lymphoma of ocular adnexal origin: usefulness of fluorescence in situ hybridization for distinction between mantle cell lymphoma and MALT lymphoma

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type (MALT lymphoma) usually lacks CD5 expression. Herein is described two cases of CD5-positive MALT lymphoma of ocular adnexal origin. The differential diagnosis between CD5-positive MALT lymphoma and mantle cell lymphoma (MCL), notably cyclin D1-negative MCL, was difficult because both cases consisted histologically of small to medium-sized cells with diffuse or vaguely nodular growth pattern, and the neoplastic cells were positive for CD5 and negative for cyclin D1. Somatic mutation analysis of the immunoglobulin heavy chain variable region (VH) gene in case 1 found a relatively higher mutation frequency (5.0%), which was not definitive to rule out MCL. Interphase fluorescence in situ hybridization (FISH) on paraffin-embedded section using IgH/cyclin D1 (CCND1) probe showed that in both cases there was no molecular evidence of t(11;14), finally leading to the diagnosis of CD5-positive MALT lymphoma. Although the present two patients had no recurrence over 34 months after initial diagnosis, careful observation is needed because the clinicopathological significance of MALT lymphoma with this rare phenotype remains obscure.

Interphase fluorescence in situ hybridization is more sensitive than BIOMED-2 polymerase chain reaction protocol in detecting IGH-BCL2 rearrangement in both fixed and frozen lymph node with follicular lymphoma

The detection of t(14;18)(q32;q21) is advisable for the diagnosis of follicular lymphoma (FL). In 51 patients with FL, we evaluated the applicability and sensitivity of interphase fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) using commercially available reagents. In 23 patients, only a formalin-fixed lymph node was available. In 28 patients, both frozen and formalin-fixed lymph nodes were evaluated. Fluorescence in situ hybridization was found to be 100% applicable whatever the material type. With the use of IGH-BCL2 dual-fusion, dual-color probes, t(14;18) translocation was detected in 47 (92%) of 51 FL cases with concordant results between isolated nuclei (n = 41) and frozen cytologic imprints (n = 28). Twenty-two IGH-BCL2-positive cases were also studied on fixed sections with BCL2 split signal probes showing a BCL2 split in all. Conversely, no BCL2 split was observed in IGH-BCL2-negative cases (n = 4). Owing to DNA degradation as assessed by the failure of control genes amplification, the applicability of PCR was found to be 76% in fixed lymph nodes (n = 51). After exclusion of the 12 noninformative cases, the BIOMED-2 protocol allowed the detection of an IGH-BCL2 fusion in 25 (64%) of 39 fixed specimens with 11 PCR-negative (31%) of 36 FISH-positive cases. Even on frozen material with 100% applicability, the amplification of a BCL2-JH breakpoint was achieved in only 20 (71%) of 28 cases with 5 PCR-negative (20%) out of 25 FISH-positive cases. Therefore, FISH was found superior to PCR (using BIOMED-2 protocol) in detecting IGH-BCL2 fusion. Finally, FISH individualized 4 IGH-BCL2-negative FL cases without specific histopathologic features. With the use of split signal DNA probes, 1 case showed a trisomy of the BCL2 locus and another displayed BCL6 and IGH breakpoints that would suggest a t(3;14). Whether such IGH-BCL2-negative cases are characterized by alternative oncogenetic pathways remains to be determined.

Gastrointestinal involvement in mantle cell lymphoma: a prospective clinic, endoscopic, and pathologic study

The frequency of gastrointestinal (GI) tract involvement in mantle cell lymphoma (MCL) at diagnosis is reported to be below 30%. To investigate the actual frequency of GI involvement by MCL, upper and lower endoscopy was prospectively performed on 13 untreated MCL patients at diagnosis. Multiple biopsies from endoscopically normal and abnormal gastric and colonic mucosa were studied with immunohistochemistry (IHC) for CD20, CD5, and cyclin D1, as well as fluorescence in situ hybridization (FISH) for t(11;14) and polymerase chain reaction (PCR) for immunoglobulin heavy chain gene. Abnormal mucosa was identified in 38% of cases by upper endoscopy (mainly mild nonspecific gastritis) and in 54% of cases by lower endoscopy (mostly micropolyps). Histologically, infiltration by MCL was demonstrated in the stomach in 77% of cases and in the colon in 77% of cases. As a whole, 92% of patients showed upper or lower GI tract infiltration by MCL. Histologic evidence of MCL involvement was present in all cases with endoscopically abnormal mucosa, but it was also observed in two-thirds of cases with endoscopically unremarkable mucosa. Positive cyclin D1 IHC was seen in all instances displaying CD20 and CD5-positive lymphoid infiltrates, whereas t(11;14) was demonstrated by FISH in 63.5% and PCR was clonal in 64% of those instances. In conclusion, the great majority of MCL patients showed GI tract involvement at the time of diagnosis, not uncommonly in the form of minute lymphoid infiltrates. IHC for cyclin D1 was significantly more sensitive than FISH t(11;14) or PCR for immunoglobulin heavy chain gene to confirm MCL in this setting.

FISH analysis for the detection of lymphoma-associated chromosomal abnormalities in routine paraffin-embedded tissue

Over the last decade, fluorescence in situ hybridization (FISH) has become a firmly established technique in the diagnosis and assessment of lymphoid malignancies. However, this technique is not wide-ly used in the routine diagnostic evaluation of paraffin-embedded biopsies, most likely because of a perception that it is technically more demanding. There are also uncertainties regarding diagnostic thresholds and the way in which results should be interpreted. In this Review, we describe practical strategies for using FISH analysis to detect lymphoma-associated chromosomal abnormalities in routine paraffin-embedded lymphoma biopsies. Furthermore, we provide proposals on how FISH results should be interpreted (including how to calculate cutoff levels for FISH probes), recorded, and reported. An online appendix (available at http://jmd.amjpathol.org) details various simple, yet robust procedures for paraffin FISH analysis; it also provides additional information on the production of FISH probes, evaluating and reporting FISH results, sources for reagents and equipment, and troubleshooting. We hope that these suggestions will make FISH technology for the study of lymphoma biopsies more accessible to routine diagnostic and research laboratories.

Automatized assessment of 1p36-19q13 status in gliomas by interphase FISH assay on touch imprints of frozen tumours

Molecular genetic analyses have demonstrated that combined losses in 1p36 and 19q13 were associated with a good response to treatment and a higher survival rates in oligodendrogliomas (O). The presence of such deletions in a subset of mixed oligoastrocytomas (OA) also suggests that 1p-19q status may assist the histological classification of gliomas. Representative frozen fragments of 25 patients with a primary grade II or III glioma [2 O, 8 astrocytic tumours (A), 15 OA] were selected and a sensitive interphase fluorescent in situ hybridization (FISH) analysis was developed on serial touch preparations using two sets of probes. A positive detection threshold at 6% was reached by the use of both touch imprints and a new set of LSI 1p36/19q13 Abbott-Vysis probes. Strong and discrete hybridization signals of these probes facilitated the following FISH analysis; indeed, an automatic analysis of the hybridization patterns (Metafer 4, Metasystems, Althlussheim, Germany) was compared with visual counting. Both methods were highly correlated and combined 1p-19q losses found in five tumours with an oligodendroglial component (2 O, 3 OA). The automatic system allowed the capture and storage of hybridization patterns and the processing of several slides. A convenient checking of the nuclei gallery was done with direct recall and visual verification on the slides of nuclei with ambiguous hybridization patterns. The recently developed probes together with automatic counting may facilitate multicentric evaluation and standardization of 1p-19q assessment in gliomas.

Cytogenetics of lymphomas

Cytogenetic analysis is now a routine part of the diagnosis and management of a significant number of lymphoid malignancies. Whilst conventional cytogenetics remains the most comprehensive method for assessing chromosome abnormalities, the technical difficulties associated with conventional cytogenetics in most lymphomas has resulted in increased use of fluorescence in situ hybridisation (FISH) to identify specific abnormalities that are useful in either the diagnosis or management of these disorders. The finding of one of the Burkitt's translocations is of major importance in the diagnosis of Burkitt's and Burkitt's-like lymphomas, whereas the t(14;18), although seen in most follicular lymphomas (FL), is not usually required to make a diagnosis. Thus, whilst cytogenetics may be of interest in FL, it is not an essential part of the diagnostic work-up. Conventional cytogenetics may be useful for identifying markers of resistance to Helicobacter pylori therapy in MALT lymphomas. In disorders such as Hodgkin lymphoma, hairy cell leukaemia and lymphoplasmacytoid lymphoma, although many cytogenetic abnormalities have been observed, no consistent or specific abnormalities have been identified and so, at this point in our knowledge of the genetics of these disorders, cytogenetics cannot be considered a useful test for either diagnosis or prognosis. In contrast, the diagnosis of mantle cell lymphoma is now dependent upon the identification of the 11;14 translocation that results in cyclin D1 up-regulation. It is widely acknowledged that FISH is the most consistently useful test to identify the juxtaposition of the CCND1 and IGH genes in mantle cell lymphoma and is regarded as the 'gold standard'. FISH also has a role in identifying genetic abnormalities of prognostic significance in chronic lymphocytic leukaemia. Given the wealth of genetic and cytogenetic abnormalities that are continuing to be found in chronic lymphoid malignancies, it will be some time before the optimal use of both conventional cytogenetics and FISH is established in the diagnosis and management of lymphomas.