Gene expression profiles of cutaneous B cell lymphoma

Emerging Insights into Liver X Receptor α in the Tumorigenesis and Therapeutics of Human Cancers

Liver X receptor α (LXRα), a member of the nuclear receptor superfamily, is identified as a protein activated by ligands that interacts with the promoters of specific genes. It regulates cholesterol, bile acid, and lipid metabolism in normal physiological processes, and it participates in the development of some related diseases. However, many studies have demonstrated that LXRα is also involved in regulating numerous human malignancies. Aberrant LXRα expression is emerging as a fundamental and pivotal factor in cancer cell proliferation, invasion, apoptosis, and metastasis. Herein, we outline the expression levels of LXRα between tumor tissues and normal tissues via the Oncomine and Tumor Immune Estimation Resource (TIMER) 2.0 databases; summarize emerging insights into the roles of LXRα in the development, progression, and treatment of different human cancers and their diversified mechanisms; and highlight that LXRα can be a biomarker and therapeutic target in diverse cancers.

An integrative bioinformatics investigation and experimental validation of chromobox family in diffuse large B-cell lymphoma

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is one of the most aggressive malignant tumors. Chromobox (CBX) family plays the role of oncogenes in various malignancies.

METHODS

The transcriptional and protein levels of CBX family were confirmed by GEPIA, Oncomine, CCLE, and HPA database. Screening of co-expressed genes and gene function enrichment analysis were performed by GeneMANIA and DAVID 6.8. The prognostic value, immune cell infiltration and drug sensitivity analysis of CBX family in DLBCL were performed by Genomicscape, TIMER2.0, and GSCALite database. Confirmatory Tests of CBX family protein expression in DLBCL were performed by immunohistochemistry.

RESULTS

The mRNA and protein expressions of CBX1/2/3/5/6 were higher in DLBCL tissues than control groups. Enrichment analysis showed that the functions of CBX family were mainly related to chromatin remodeling, methylation-dependent protein binding, and VEGF signaling pathway. The high mRNA expressions of CBX2/3/5/6 were identified to be associated with short overall survival (OS) in DLBCL patients. Multivariate COX regression indicated that CBX3 was independent prognostic marker. Immune infiltration analysis revealed that the mRNA expressions of CBX family (especially CBX1, CBX5, and CBX6) in DLBCL were significantly correlated with the infiltration of most immune cells (including B cells, CD8 + T cells, CD4 + T cells, neutrophils, monocytes, macrophages, and Treg cells). Meanwhile, there was a strong correlation between the expression levels of CBX1/5/6 and surface markers of immune cells, such as the widely studied PVR-like protein receptor/ligand and PDL-1 immune checkpoint. Notably, our study found that DLBCL cells with CBX1 over-expression were resistant to the common anti-tumor drugs, but CBX2/5 had two polarities. Finally, we confirmed the higher expressions of CBX1/2/3/5/6 in DLBCL tissues compared with control groups by immunohistochemistry.

CONCLUSION

We provided a detailed analysis of the relationship between the CBX family and the prognosis of DLBCL. Distinguished from other studies, We found that high mRNA expressions of CBX2/3/5/6 were associated with poor prognosis in DLBCL patients, and Multivariate COX regression indicated that CBX3 was independent prognostic marker. Besides, our study also found an association between the CBX family and anti-tumour drug resistance, and provided a relationship between CBX family expression and immune cell infiltration.

Expression and Significance of Cyclin-Dependent Protein Kinase 6 in Diffuse Large B-Cell Lymphoma

Objective

To study the relationship between cyclin-dependent protein kinase 6 (CDK6) expression in diffuse large B-cell lymphoma (DLBCL) and the clinical biological behavior and prognosis.

Methods

Data mining was performed using the Oncomine and The Cancer Genome Atlas (TCGA) databases to analyze the expression level of CDK6 in DLBCL. CDK6 alterations in DLBCL and related functional networks were analyzed with c-BioPortal and the Gene Set Enrichment Analysis was performed by using DAVID and FunRich software. In addition, screening for differential gene expression of CDK6 was done and enriched by using LinkedOmics. Finally, formalin-fixed and paraffin-embedded (FFPE) tissue samples from 102 patients with DLBCL were collected from the Department of Pathology, Shanxi Cancer Hospital (Taiyuan, Shanxi, China) from January 2015 through December 2020. All cases had complete clinical course records. Thirty cases of lymph node reactive hyperplasia tissues were used as controls. The expression of CDK6 in DLBCL tissues was detected by qRT‑PCR and immunohistochemistry.

Results

Bioinformatics analysis: The data showed that mRNA expression level and DNA copy number variations (CNVs) of CDK6 were significantly higher in DLBCL as compared to normal tissue (P ˂ 0.05). Based on C-BioPortal analysis, we speculated that amplification was the most common copy of CDK6 CNV in DLBCL. Through Gene Ontology (GO) analysis of these genes, it was found that the proteins were mainly located in the nucleus and cytoplasm. The biological interaction network of CDK6 alterations were found to participate primarily in the G1-S phase of the process. Analysis of LinkedOmics mRNA sequencing data showed that three genes were positively correlated with CDK6 expression: PSMD1, C2orf29 and ASB1. Through experimental verification, we found that CDK6 was overexpressed in DLBCL, and the expression of CDK6 mRNA and protein in DLBCL were positively correlated with Ann Arbor staging and IPI score (P<0.05), and negatively correlated with overall survival (P<0.001).

Conclusion

Data mining results and experiments revealed and confirmed multi-level evidence for the importance of CDK6 in DLBCL; hence, CDK6 may be a potential marker in DLBCL. Thus, our study will perhaps lay the foundation for further research on the role of CDK6 in the genesis and development of DLBCL.

Comprehensive Landscape of STEAP Family Members Expression in Human Cancers: Unraveling the Potential Usefulness in Clinical Practice Using Integrated Bioinformatics Analysis

The human Six-Transmembrane Epithelial Antigen of the Prostate (STEAP) family comprises STEAP1-4. Several studies have pointed out STEAP proteins as putative biomarkers, as well as therapeutic targets in several types of human cancers, particularly in prostate cancer. However, the relationships and significance of the expression pattern of STEAP1-4 in cancer cases are barely known. Herein, the Oncomine database and cBioPortal platform were selected to predict the differential expression levels of STEAP members and clinical prognosis. The most common expression pattern observed was the combination of the over- and underexpression of distinct STEAP genes, but cervical and gastric cancer and lymphoma showed overexpression of all STEAP genes. It was also found that STEAP genes’ expression levels were already deregulated in benign lesions. Regarding the prognostic value, it was found that STEAP1 (prostate), STEAP2 (brain and central nervous system), STEAP3 (kidney, leukemia and testicular) and STEAP4 (bladder, cervical, gastric) overexpression correlate with lower patient survival rate. However, in prostate cancer, overexpression of the STEAP4 gene was correlated with a higher survival rate. Overall, this study first showed that the expression levels of STEAP genes are highly variable in human cancers, which may be related to different patients’ outcomes.

Comprehensive analysis of the expression and significance of CXCLs in human diffuse large B-cell lymphoma

CXCL chemokines (CXCLs) are small cytokines or signal proteins secreted by cells that have been proven to be linked to the occurrence and development of many kinds of cancer. However, the expression and diagnostic and prognostic value of CXCLs in diffuse large B-cell lymphoma (DLBCL) remain to be further studied. We obtained CXCL transcription and survival data of patients with DLBCL from Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), The Cancer Genome Atlas (TCGA), TIMER and cBioPortal databases. R software, STRING and EXCEL were used to process the data. This study discovered that the expression levels of CXCL9-14 in DLBCL were higher than those in normal tissues, while CXCL4, CXCL7 and CXCL8 were lower in tumor than in normal tissues. The expression levels of CXCL2, CXCL10 and CXCL11 were related to tumor stage. CXCL9-14 could be used as an auxiliary molecular marker for the diagnosis of DLBCL. CXCL17 might be a potential prognostic marker of DLBCL.

Immunohistochemical algorithms and gene expression profiling in primary cutaneous B-cell lymphoma

OBJECTIVE

to assess whether immunohistochemical (IHC) algorithms used to classify the cell of origin (COO) of nodal Diffuse Large B-cell lymphoma (nDLBCL) in Germinal Center type (GCB) and non-GCB subtypes may be applied to Primary Cutaneous B-cell lymphoma (PCBCL) too, and which of these algorithms performs better on PCBCL.

DESIGN

Retrospective case control study.

SETTING

Pathology Department of the University Hospital "San Giovanni di Dio e Ruggi d'Aragona" Salerno, Italy.

PARTICIPANTS

Fourteen PCBCL, including Primary Cutaneous follicle centre lymphoma (PCFCL) and primary cutaneous diffuse large B-cell lymphoma, Leg type (PCDLBCL-LT) and 14 nDLBCL were evaluated for 7-year period (January 2011 to December 2017). Primary cutaneous marginal zone cell lymphoma (PCMZL) cases were not included in the present study.

INTERVENTION

Evaluation of immunohistochemical CD10, BCL6, MUM1/IRF4, BCL2, MYC and Ki-67 expression and classification according to three different algorithms. Gene expression profiling (GEP) was performed on the same series using Lymph2Cx assay (Nanostring). The data obtained were compared and analysed.

RESULTS

All the IHC algorithms showed 13 GCB and 15 non-GCB. GEP showed 12 GCB, 12 activated B cell-type and 4 unclassified.

CONCLUSIONS

The PCBCL were classifiable as GCB and non-GCB like the nDLBCL as IHC algorithms were concordant to GEP and produced the same results.

Roles and Regulation of BCL-xL in Hematological Malignancies

Members of the Bcl-2 family are proteins that play an essential role in the regulation of apoptosis, a crucial process in development and normal physiology in multicellular organisms. The essential mechanism of this family of proteins is given by the role of pro-survival proteins, which inhibit apoptosis by their direct binding with their counterpart, the effector proteins of apoptosis. This family of proteins was named after the typical member Bcl-2, which was named for its discovery and abnormal expression in B-cell lymphomas. Subsequently, the structure of one of its members BCL-xL was described, which allowed one to understand much of the molecular mechanism of this family. Due to its role of BCL-xL in the regulation of cell survival and proliferation, it has been of great interest in its study. Due to this, it is important to research its role regarding the development and progression of human malignancies, especially in hematologic malignancies. Due to its variation in expression in cancer, it has been suggested that BCL-xL can or cannot play a role in cancer depending on the cellular or tissue context. This review discusses recent advances in its transcriptional regulation of BCL-xL, as well as the advances regarding the activities of BCL-xL in hematological malignancies, its possible role as a biomarker, and its possible clinical relevance in these malignancies.

CCR7 in Blood Cancers - Review of Its Pathophysiological Roles and the Potential as a Therapeutic Target

According to the classical paradigm, CCR7 is a homing chemokine receptor that grants normal lymphocytes access to secondary lymphoid tissues such as lymph nodes or spleen. As such, in most lymphoproliferative disorders, CCR7 expression correlates with nodal or spleen involvement. Nonetheless, recent evidence suggests that CCR7 is more than a facilitator of lymphatic spread of tumor cells. Here, we review published data to catalogue CCR7 expression across blood cancers and appraise which classical and novel roles are attributed to this receptor in the pathogenesis of specific hematologic neoplasms. We outline why novel therapeutic strategies targeting CCR7 might provide clinical benefits to patients with CCR7-positive hematopoietic tumors.

Comprehensive Analysis of Hexokinase 2 Immune Infiltrates and m6A Related Genes in Human Esophageal Carcinoma

Background: Hexokinase 2 not only plays a role in physiological function of human normal tissues and organs, but also plays a vital role in the process of glycolysis of tumor cells. However, there are few comprehensive studies on HK2 in esophageal carcinoma (ESCA) needs further study.

Methods: Oncomine, Tumor Immune Estimation Resource (TIMER), The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database were used to analyze the expression differences of HK2 in Pan-cancer and ESCA cohort, and to analyze the correlation between HK2 expression level and clinicopathological features of TCGA ESCA samples. GO/KEGG, GGI, and PPI analysis of HK2 was performed using R software, LinkedOmics, GeneMANIA and STRING online tools. The correlation between HK2 and ESCA immune infiltration was analyzed TIMER and TCGA ESCA cohort. The correlation between HK2 expression level and m6A modification of ESCA was analyzed by utilizing TCGA ESCA cohort.

Results: HK2 is highly expressed in a variety of tumors, and its high expression level in ESCA is closely related to the weight, cancer stages, tumor histology and tumor grade of ESCA. The analysis results of GO/KEGG showed that HK2 was closely related to cell adhesion molecule binding, cell-cell junction, ameboidal-type cell migration, insulin signaling pathway, hif-1 signaling pathway, and insulin resistance. GGI showed that HK2 associated genes were mainly involved in the glycolytic pathway. PPI showed that HK2 was closely related to HK1, GPI, and HK3, all of which played an important role in tumor proliferation. The analysis results of TIMER and TCGA ESCA cohort indicated that the HK2 expression level was related to the infiltration of various immune cells. TCGA ESCA cohort analyze indicated that the HK2 expression level was correlated with m6A modification genes.

Conclusion: HK2 is associated with tumor immune infiltration and m6A modification of ESCA, and can be used as a potential biological target for diagnosis and therapy of ESCA.

Function of Deptor and its roles in hematological malignancies

Deptor is a protein that interacts with mTOR and that belongs to the mTORC1 and mTORC2 complexes. Deptor is capable of inhibiting the kinase activity of mTOR. It is well known that the mTOR pathway is involved in various signaling pathways that are involved with various biological processes such as cell growth, apoptosis, autophagy, and the ER stress response. Therefore, Deptor, being a natural inhibitor of mTOR, has become very important in its study. Because of this, it is important to research its role regarding the development and progression of human malignancies, especially in hematologic malignancies. Due to its variation in expression in cancer, it has been suggested that Deptor can act as an oncogene or tumor suppressor depending on the cellular or tissue context. This review discusses recent advances in its transcriptional and post-transcriptional regulation of Deptor. As well as the advances regarding the activities of Deptor in hematological malignancies, its possible role as a biomarker, and its possible clinical relevance in these malignancies.

Diffuse large B cell lymphoma progression with skin involvement: A case report

Diffuse large B cell lymphoma (DLBCL) constitutes the most frequent subtype of all non-Hodgkin's lymphomas. DLBCL is an aggressive disease and extranodal involvement is seen in approximately 30% of patients and most common extranodal sites are gastointestinal tract and skin. Skin involvement may be either primary or secondary. Secondary cutaneous lymphoma has a worse prognosis. The case is here reported of a 56-year old male DLBCL patient with cutaneous lesions and aggressive clinical course. The patient had no skin lesions at diagnosis and during follow up and treatment period, skin, cerebrospinal fluid and bone marrow involvement was occurred. Salvage chemotherapy and autologous stem cell transplantation was planned but the patient died before the second cycle of salvage chemotherapy. In contrast to primary cutaneous lymphoma, which tends to be more indolent, secondary skin involvement is associated with unfavourable prognosis. In conclusion it should be kept in mind that skin can be involved in lymphoma patients and in these cases, skin biopsy should be performed rapidly.

Meta-analysis of gene expression alterations and clinical significance of the HECT domain-containing ubiquitin ligase HUWE1 in cancer

E3 ubiquitin-protein ligase (HUWE1) has previously been identified as a HECT domain-containing ubiquitin ligase (E3) that is involved in several signaling pathways, transcriptional regulation, neural differentiation, DNA damage responses and apoptosis. However, the function of HUWE1 in the various types of cancer remains unclear. A previous study indicated that HUWE1 exhibited different roles depending on the cancer type due to the ubiquitination of various substrates. The objective of the present study was to determine whether HUWE1 can be employed as a prognostic indicator in human cancer. The expression of HUWE1 was examined using the Oncomine database, and gene alterations during carcinogenesis, copy number alterations and mutations of HUWE1 were then analyzed using cBioPortal, which is the International Cancer Genome Consortium and the Tumorscape database. Furthermore, the association between HUWE1 expression and patient survival was evaluated using Kaplan-Meier plotter and the PrognoScan databases. In addition, the present study attempted to establish the functional association between HUWE1 expression and cancer phenotypes, and the results revealed that HUWE1 may serve as a diagnostic marker or therapeutic target for certain types of cancer. HUWE1 may serve an oncogenic role in breast, brain and prostate cancer, while it may serve an anti-oncogenic role in colorectal cancer and certain lung cancers. The function of HUWE1 and its mechanisms require more in-depth and extensive investigation in future studies.

Cancer-type dependent expression of CK2 transcripts

A multitude of proteins are aberrantly expressed in cancer cells, including the oncogenic serine-threonine kinase CK2. In a previous report, we found increases in CK2 transcript expression that could explain the increased CK2 protein levels found in tumors from lung and bronchus, prostate, breast, colon and rectum, ovarian and pancreatic cancers. We also found that, contrary to the current notions about CK2, some CK2 transcripts were downregulated in several cancers. Here, we investigate all other cancers using Oncomine to determine whether they also display significant CK2 transcript dysregulation. As anticipated from our previous analysis, we found cancers with all CK2 transcripts upregulated (e.g. cervical), and cancers where there was a combination of upregulation and/or downregulation of the CK2 transcripts (e.g. sarcoma). Unexpectedly, we found some cancers with significant downregulation of all CK2 transcripts (e.g. testicular cancer). We also found that, in some cases, CK2 transcript levels were already dysregulated in benign lesions (e.g. Barrett’s esophagus). We also found that CK2 transcript upregulation correlated with lower patient survival in most cases where data was significant. However, there were two cancer types, glioblastoma and renal cell carcinoma, where CK2 transcript upregulation correlated with higher survival. Overall, these data show that the expression levels of CK2 genes is highly variable in cancers and can lead to different patient outcomes.

Voltage-gated calcium channels: Novel targets for cancer therapy

Voltage-gated calcium channels (VGCCs) comprise five subtypes: The L-type; R-type; N-type; P/Q-type; and T-type, which are encoded by α₁ subunit genes. Calcium ion channels also have confirmed roles in cellular functions, including mitogenesis, proliferation, differentiation, apoptosis and metastasis. An association between VGCCs, a reduction in proliferation and an increase in apoptosis in prostate cancer cells has also been reported. Therefore, in the present study, the online clinical database Oncomine was used to identify the alterations in the mRNA expression level of VGCCs in 19 cancer subtypes. Overall, VGCC family genes exhibited under-expression in numerous types of cancer, including brain, breast, kidney and lung cancers. Notably, the majority of VGCC family members (CACNA1C, CACNA1D, CACNA1A, CACNA1B, CACNA1E, CACNA1H and CACNA1I) exhibited low expression in brain tumors, with mRNA expression levels in the top 1–9% of downregulated gene rankings. A total of 5 VGCC family members (CACNA1A, CACNA1B, CACNA1E, CACNA1G and CACNA1I) were under-expressed in breast cancer, with a gene ranking in the top 1–10% of the low-expressed genes compared with normal tissue. In kidney and lung cancers, CACNA1S, CACNA1C, CACNA1D, CACNA1A and CACNA1H exhibited low expression, with gene rankings in the top 1–8% of downregulated genes. In conclusion, the present findings may contribute to the development of new cancer treatment approaches by identifying target genes involved in specific types of cancer.

Impact of intracellular ion channels on cancer development and progression

Cancer research is nowadays focused on the identification of possible new targets in order to try to develop new drugs for curing untreatable tumors. Ion channels have emerged as "oncogenic" proteins, since they have an aberrant expression in cancers compared to normal tissues and contribute to several hallmarks of cancer, such as metabolic re-programming, limitless proliferative potential, apoptosis-resistance, stimulation of neo-angiogenesis as well as cell migration and invasiveness. In recent years, not only the plasma membrane but also intracellular channels and transporters have arisen as oncological targets and were proposed to be associated with tumorigenesis. Therefore, the research is currently focusing on understanding the possible role of intracellular ion channels in cancer development and progression on one hand and, on the other, on developing new possible drugs able to modulate the expression and/or activity of these channels. In a few cases, the efficacy of channel-targeting drugs in reducing tumors has already been demonstrated in vivo in preclinical mouse models.

Cutaneous primary B-cell lymphomas: from diagnosis to treatment

Primary cutaneous B-cell lymphomas are a heterogeneous group of mature B-cells neoplasms with tropism for the skin, whose biology and clinical course differ significantly from the equivalent nodal lymphomas. The most indolent forms comprise the primary cutaneous marginal zone and follicle center B-cell lymphomas that despite the excellent prognosis have cutaneous recurrences very commonly. The most aggressive forms include the primary cutaneous large B-cell lymphomas, consisting in two major groups: the leg type, with poor prognosis, and others, the latter representing a heterogeneous group of lymphomas from which specific entities are supposed to be individualized over time, such as intravascular large B-cell lymphomas. Treatment may include surgical excision, radiotherapy, antibiotics, corticosteroids, interferon, monoclonal antibodies and chemotherapy, depending on the type of lymphoma and on the type and location of the skin lesions. In subtypes with good prognosis is contraindicated overtreatment and in those associated with a worse prognosis the recommended therapy relies on CHOP-like regimens associated with rituximab, assisted or not with local radiotherapy. We review the primary cutaneous B-cell lymphomas, remembering the diagnostic criteria, differential diagnosis, classification, and prognostic factors and presenting the available therapies.

Meta-Analysis of Public Microarray Datasets Reveals Voltage-Gated Calcium Gene Signatures in Clinical Cancer Patients

Voltage-gated calcium channels (VGCCs) are well documented to play roles in cell proliferation, migration, and apoptosis; however, whether VGCCs regulate the onset and progression of cancer is still under investigation. The VGCC family consists of five members, which are L-type, N-type, T-type, R-type and P/Q type. To date, no holistic approach has been used to screen VGCC family genes in different types of cancer. We analyzed the transcript expression of VGCCs in clinical cancer tissue samples by accessing ONCOMINE (www.oncomine.org), a web-based microarray database, to perform a systematic analysis. Every member of the VGCCs was examined across 21 different types of cancer by comparing mRNA expression in cancer to that in normal tissue. A previous study showed that altered expression of mRNA in cancer tissue may play an oncogenic role and promote tumor development; therefore, in the present findings, we focus only on the overexpression of VGCCs in different types of cancer. This bioinformatics analysis revealed that different subtypes of VGCCs (CACNA1C, CACNA1D, CACNA1B, CACNA1G, and CACNA1I) are implicated in the development and progression of diverse types of cancer and show dramatic up-regulation in breast cancer. CACNA1F only showed high expression in testis cancer, whereas CACNA1A, CACNA1C, and CACNA1D were highly expressed in most types of cancer. The current analysis revealed that specific VGCCs likely play essential roles in specific types of cancer. Collectively, we identified several VGCC targets and classified them according to different cancer subtypes for prospective studies on the underlying carcinogenic mechanisms. The present findings suggest that VGCCs are possible targets for prospective investigation in cancer treatment.

Aggressive primary cutaneous B-cell lymphomas show increased Angiopoietin-2-induced angiogenesis

Primary cutaneous large B-cell lymphomas, leg type (PCLBCL/LT) are primary cutaneous B-cell lymphoma (PCBCL) with an intermediate prognosis. Therefore, antracycline-based polychemotherapy combined with rituximab has been recommended as first-line treatment. Yet, despite this regimen, the 5-year survival rate remains 50-66% only. Angiogenesis, the formation of a vascular network, is essential for the pathogenesis of nodal lymphomas. So far, no study has analysed angiogenesis and its key factors in PCLBCL/LT. The present study was aimed at characterizing angiogenesis in PCLBCL/LT to identify the angiogenic molecules as potential therapeutic targets. The intra-tumoral microvessel density (MVD) was assessed by immunohistochemical studies of CD20 and CD31. The MVD was higher in PCLBCL/LT compared with indolent PCBCL. Analyses of open-source microarray data showed correlation between the angiogenic molecule angiopoietin-2 (Ang-2) and pan-endothelial cell markers. ELISA studies determined a shift between Ang-2 and Ang-1 towards Ang-2 in the peripheral blood of PCLBCL/LT patients. Immunofluorescence costainings against the Ang receptor Tie2/angiogenic integrins/CD34 revealed that the vasculature in both aggressive and indolent PCBCL tumors harbours an endothelial cell subpopulation with reduced expression of Tie2. In contrast, the alternative Ang-2 binding partners, angiogenic integrins, are strongly expressed in PCBCL. In line with these findings, downstream targets of Ang-2-integrin signalling, that is phosphorylation of focal adhesion kinase at Tyr397, and sprouting angiogenesis are enhanced in PCLBCL/LT. Our data present Ang-2 as a promising therapeutic target and anti-angiogenic therapy as a new line in treatment of PCLBCL/LT as a hitherto intractable disease.

CHCHD2 inhibits apoptosis by interacting with Bcl-x L to regulate Bax activation

Mitochondrial outer membrane permeabilization (MOMP) is a critical control point during apoptosis that results in the release of pro-apoptotic mitochondrial contents such as cytochrome c. MOMP is largely controlled by Bcl-2 family proteins such as Bax, which under various apoptotic stresses becomes activated and oligomerizes on the outer mitochondrial membrane. Bax oligomerization helps promote the diffusion of the mitochondrial contents into the cytoplasm activating the caspase cascade. In turn, Bax is regulated primarily by anti-apoptotic Bcl-2 proteins including Bcl-xL, which was recently shown to prevent Bax from accumulating at the mitochondria. However, the exact mechanisms by which Bcl-xL regulates Bax and thereby MOMP remain partially understood. In this study, we show that the small CHCH-domain-containing protein CHCHD2 binds to Bcl-xL and inhibits the mitochondrial accumulation and oligomerization of Bax. Our data show that in response to apoptotic stimuli, mitochondrial CHCHD2 decreases prior to MOMP. Furthermore, when CHCHD2 is absent from the mitochondria, the ability of Bcl-xL to inhibit Bax activation and to prevent apoptosis is attenuated, which results in increases in Bax oligomerization, MOMP and apoptosis. Collectively, our findings establish CHCHD2, a previously uncharacterized small mitochondrial protein with no known homology to the Bcl-2 family, as one of the negative regulators of mitochondria-mediated apoptosis.

NIAM-deficient mice are predisposed to the development of proliferative lesions including B-cell lymphomas

Nuclear Interactor of ARF and Mdm2 (NIAM, gene designation Tbrg1) is a largely unstudied inhibitor of cell proliferation that helps maintain chromosomal stability. It is a novel activator of the ARF-Mdm2-Tip60-p53 tumor suppressor pathway as well as other undefined pathways important for genome maintenance. To examine its predicted role as a tumor suppressor, we generated NIAM mutant (NIAM^m/m) mice homozygous for a β-galactosidase expressing gene-trap cassette in the endogenous gene. The mutant mice expressed significantly lower levels of NIAM protein in tissues compared to wild-type animals. Fifty percent of aged NIAM deficient mice (14 to 21 months) developed proliferative lesions, including a uterine hemangioma, pulmonary papillary adenoma, and a Harderian gland adenoma. No age-matched wild-type or NIAM^+/m heterozygous animals developed lesions. In the spleen, NIAM^m/m mice had prominent white pulp expansion which correlated with enhanced increased reactive lymphoid hyperplasia and evidence of systemic inflammation. Notably, 17% of NIAM mutant mice had splenic white pulp features indicating early B-cell lymphoma. This correlated with selective expansion of marginal zone B cells in the spleens of younger, tumor-free NIAM-deficient mice. Unexpectedly, basal p53 expression and activity was largely unaffected by NIAM loss in isolated splenic B cells. In sum, NIAM down-regulation in vivo results in a significant predisposition to developing benign tumors or early stage cancers. These mice represent an outstanding platform for dissecting NIAM's role in tumorigenesis and various anti-cancer pathways, including p53 signaling.

Patterns of TPD52 overexpression in multiple human solid tumor types analyzed by quantitative PCR

Tumor protein D52 (TPD52) is located at chromosome 8q21, a region that is frequently gained or amplified in multiple human cancer types. TPD52 has been suggested as a potential target for new anticancer therapies. In order to analyze TPD52 expression in the most prevalent human cancer types, we employed quantitative PCR to measure TPD52 mRNA levels in formalin-fixed tissue samples from more than 900 cancer tissues obtained from 29 different human cancer types. TPD52 was expressed at varying levels in all tested normal tissues, including skin, lymph node, lung, oral mucosa, breast, endometrium, ovary, vulva, myometrium, liver, pancreas, stomach, kidney, prostate, testis, urinary bladder, thyroid gland, brain, muscle and fat tissue. TPD52 was upregulated in 18/29 (62%) tested cancer types. Strongest expression was found in non-seminoma (56-fold overexpression compared to corresponding normal tissue), seminoma (42-fold), ductal (28-fold) and lobular breast cancer (14-fold). In these tumor types, TPD52 upregulation was found in the vast majority (>80%) of tested samples. Downregulation was found in 11 (38%) tumor types, most strongly in papillary renal cell cancer (-8-fold), leiomyosarcoma (-6-fold), clear cell renal cell cancer (-5-fold), liposarcoma (-5-fold) and lung cancer (-4-fold). These results demonstrate that TPD52 is frequently and strongly upregulated in many human cancer types, which may represent candidate tumor types for potential anti-TPD52 therapies.

Cutaneous telangiectasia and cauda equina syndrome: a presentation of diffuse large B-cell lymphoma

We describe a 72-year-old woman with striking cutaneous telangiectatic lesions that chronologically preceded presentation with cauda equina syndrome. Diffuse large B-cell lymphoma (DLBCL) was confirmed on skin biopsies from plaques on the abdominal wall and left ankle, the possibilities including primary cutaneous DLBCL leg-type or systemic DLBCL. We speculate that this clinical appearance may arise due to lymphatic or vascular congestion resulting from the dense lymphoid infiltrate in this case.

Tissue inhibitor of metalloproteinase 1 expression associated with gene demethylation confers anoikis resistance in early phases of melanocyte malignant transformation

Although anoikis resistance has been considered a hallmark of malignant phenotype, the causal relation between neoplastic transformation and anchorage-independent growth remains undefined. We developed an experimental model of murine melanocyte malignant transformation, where a melanocyte lineage (melan-a) was submitted to sequential cycles of anchorage blockade, resulting in progressive morphologic alterations, and malignant transformation. Throughout this process, cells corresponding to premalignant melanocytes and melanoma cell lines were established and show progressive anoikis resistance and increased expression of Timp1. In melan-a melanocytes, Timp1 expression is suppressed by DNA methylation as indicated by its reexpression after 5-aza-2'-deoxycytidine treatment. Methylation-sensitive single-nucleotide primer extension analysis showed increased demethylation in Timp1 in parallel with its expression along malignant transformation. Interestingly, TIMP1 expression has already been related with negative prognosis in some human cancers. Although described as a MMP inhibitor, this protein has been associated with apoptosis resistance in different cell types. Melan-a cells overexpressing Timp1 showed increased survival in suspension but were unable to form tumors in vivo, whereas Timp1-overexpressing melanoma cells showed reduced latency time for tumor appearance and increased metastatic potential. Here, we demonstrated for the first time an increment in Timp1 expression since the early phases of melanocyte malignant transformation, associated to a progressive gene demethylation, which confers anoikis resistance. In this way, Timp1 might be considered as a valued marker for melanocyte malignant transformation.

The emerging role of CXCL10 in cancer (Review)

The chemokine interferon-γ inducible protein 10 kDa (CXCL10) is a member of the CXC chemokine family which binds to the CXCR3 receptor to exert its biological effects. CXCL10 is involved in chemotaxis, induction of apoptosis, regulation of cell growth and mediation of angiostatic effects. CXCL10 is associated with a variety of human diseases including infectious diseases, chronic inflammation, immune dysfuntion, tumor development, metastasis and dissemination. More importantly, CXCL10 has been identified as a major biological marker mediating disease severity and may be utilized as a prognostic indicator for various diseases. In this review, we focus on current research elucidating the emerging role of CXCL10 in the pathogenesis of cancer. Understanding the role of CXCL10 in disease initiation and progression may provide the basis for developing CXCL10 as a potential biomarker and therapeutic target for related human malignancies.

DATE analysis: A general theory of biological change applied to microarray data

In contrast to conventional data mining, which searches for specific subsets of genes (extensive variables) to correlate with specific phenotypes, DATE analysis correlates intensive state variables calculated from the same datasets. At the heart of DATE analysis are two biological equations of state not dependent on genetic pathways. This result distinguishes DATE analysis from other bioinformatics approaches. The dimensionless state variable F quantifies the relative overall cellular activity of test cells compared to well-chosen reference cells. The variable pi(i) is the fold-change in the expression of the ith gene of test cells relative to reference. It is the fraction phi of the genome undergoing differential expression-not the magnitude pi-that controls biological change. The state variable phi is equivalent to the control strength of metabolic control analysis. For tractability, DATE analysis assumes a linear system of enzyme-connected networks and exploits the small average contribution of each cellular component. This approach was validated by reproducible values of the state variables F, RNA index, and phi calculated from random subsets of transcript microarray data. Using published microarray data, F, RNA index, and phi were correlated with: (1) the blood-feeding cycle of the malaria parasite, (2) embryonic development of the fruit fly, (3) temperature adaptation of Killifish, (4) exponential growth of cultured S. pneumoniae, and (5) human cancers. DATE analysis was applied to aCGH data from the great apes. A good example of the power of DATE analysis is its application to genomically unstable cancers, which have been refractory to data mining strategies.

The BCL6-associated transcriptional co-repressor, MTA3, is selectively expressed by germinal centre B cells and lymphomas of putative germinal centre derivation

Metastasis-associated protein 3 (MTA3) is a recently described cell-type specific component of the Mi-2-NURD transcriptional co-repressor complex that is expressed in breast epithelia and germinal centre B cells. In model B cell lines, MTA3 physically interacts with BCL6 and appears to be instrumental in maintenance of the germinal centre B cell transcriptional programme that precludes premature plasmacytic differentiation. Here, we report selective, in situ cell-type specific expression of MTA3 among lymphoid cells largely confined to the germinal centre B cell compartment. Centroblasts display greater expression than smaller, less proliferative centrocytes, with undetectable expression in quiescent plasma cells. Among B cell neoplasms, germinal centre B cell-like lymphomas likewise exhibit selective expression that generally escalates with increasing proliferative capacity. MTA3 protein expression was, in accord, highly predictive of the germinal centre B cell-like gene expression profile for diffuse large B cell lymphomas. Lastly, relative repression of a subset of known BCL6 targets, including BLIMP1 and p27kip1, was highest in diffuse large B cell lymphomas that co-expressed both MTA3 and BCL6 protein. Together, these novel data suggest a role for MTA3 in BCL6-mediated lymphomagenesis in germinal centre B cell-like neoplasms.

Common human cancer genes discovered by integrated gene-expression analysis

Background

Microarray technology enables a standardized, objective assessment of oncological diagnosis and prognosis. However, such studies are typically specific to certain cancer types, and the results have limited use due to inadequate validation in large patient cohorts. Discovery of genes commonly regulated in cancer may have an important implication in understanding the common molecular mechanism of cancer.

Methods and Findings

We described an integrated gene-expression analysis of 2,186 samples from 39 studies to identify and validate a cancer type-independent gene signature that can identify cancer patients for a wide variety of human malignancies. The commonness of gene expression in 20 types of common cancer was assessed in 20 training datasets. The discriminative power of a signature defined by these common cancer genes was evaluated in the other 19 independent datasets including novel cancer types. QRT-PCR and tissue microarray were used to validate commonly regulated genes in multiple cancer types. We identified 187 genes dysregulated in nearly all cancerous tissue samples. The 187-gene signature can robustly predict cancer versus normal status for a wide variety of human malignancies with an overall accuracy of 92.6%. We further refined our signature to 28 genes confirmed by QRT-PCR. The refined signature still achieved 80% accuracy of classifying samples from mixed cancer types. This signature performs well in the prediction of novel cancer types that were not represented in training datasets. We also identified three biological pathways including glycolysis, cell cycle checkpoint II and plk3 pathways in which most genes are systematically up-regulated in many types of cancer.

Conclusions

The identified signature has captured essential transcriptional features of neoplastic transformation and progression in general. These findings will help to elucidate the common molecular mechanism of cancer, and provide new insights into cancer diagnostics, prognostics and therapy.

DNA microarrays in dermatology and skin biology

Because of its accessibility, skin has been among the first organs analyzed using DNA microarrays. Skin cancers, melanomas, and basal and squamous cell carcinomas have been intensely investigated because they are very frequent and can be fatal. Psoriasis, one of the most common human inflammatory diseases, has been studied comprehensively using DNA microarrays. In addition, epidermal keratinocytes have been the target of many studies because they respond to a rich variety of inflammatory and immunomodulating cytokines, hormones, vitamins, ultraviolet (UV) light, toxins, and physical injury. Because of the ethical considerations, the effects of harmful or dangerous agents on skin have been studied using artificial skin substitutes. Transcriptional mechanisms that regulate epidermal differentiation and cornification have begun to yield their mysteries, and very exciting recent studies identified the genes specifically expressed in epidermal stem cells. Thus, skin has everything: stem cells, differentiation, signaling, inflammation, diseases, and cancer. All these exciting facets of skin have been explored using DNA microarrays. Researchers in skin biology and dermatology were among the first to implement this technology and we expect that they will continue to generate exciting and useful new knowledge.

Cutaneous malignant lymphomas: Update 2006

Cutaneous lymphomas represent a unique group of lymphomas and are the second most frequent extranodal lymphomas. As with other neoplasias, the pathogenesis is based mainly on a stepwise accumulation of mutations of suppressor genes and oncogenes caused by genetic, environmental or infectious factors. The diagnostic work-up includes clinical, histological, imaging and hematological investigations and in many cases immunohistochemical and molecular biological analyses. The current WHO/EORTC classification of cutaneous lymphomas differentiates "mature T-cell and NK-cell lymphomas", "mature B-cell lymphomas" and "immature hematopoietic malignancies", their variants and subgroups. It is compatible with the WHO classification for neoplasias of the hematopoietic and lymphoid tissue and respects the organ-specific peculiarities of primary cutaneous lymphomas. The assignment of the various types of cutaneous lymphomas into prognostic categories (pre-lymphomatous "abortive" disorders; definite malignant lymphomas of low-grade malignancy; definite malignant lymphomas of high-grade malignancy) provides essential information on the biological behavior and allows an appropriate planning of the therapeutic strategy, which may be topical or systemic and aggressive or non-aggressive. Besides the classical options for therapy, there are new and "experimental" strategies, the efficacy of which has to be studied in clinical trials.

KLF4 suppresses transformation of pre-B cells by ABL oncogenes

Genes that are strongly repressed after B-cell activation are candidates for being inactivated, mutated, or repressed in B-cell malignancies. Krüppel-like factor 4 (Klf4), a gene down-regulated in activated murine B cells, is expressed at low levels in several types of human B-cell lineage lymphomas and leukemias. The human KLF4 gene has been identified as a tumor suppressor gene in colon and gastric cancer; in concordance with this, overexpression of KLF4 can suppress proliferation in several epithelial cell types. Here we investigate the effects of KLF4 on pro/pre-B-cell transformation by v-Abl and BCR-ABL, oncogenes that cause leukemia in mice and humans. We show that overexpression of KLF4 induces arrest and apoptosis in the G1 phase of the cell cycle. KLF4-mediated death, but not cell-cycle arrest, can be rescued by Bcl-XL overexpression. Transformed pro/pre-B cells expressing KLF4 display increased expression of p21CIP and decreased expression of c-Myc and cyclin D2. Tetracycline-inducible expression of KLF4 in B-cell progenitors of transgenic mice blocks transformation by BCR-ABL and depletes leukemic pre-B cells in vivo. Collectively, our work identifies KLF4 as a putative tumor suppressor in B-cell malignancies.

Repression of the MSP/MST-1 gene contributes to the antiapoptotic gain of function of mutant p53

Tumor-associated mutant forms of p53 can exert an antiapoptotic gain of function activity, which confers a selective advantage upon tumor cells harboring such mutations. We report that mutant p53 suppresses the expression of the MSP (MST-1/HGFL) gene, encoding the ligand of the receptor tyrosine kinase RON, implicated in a variety of cellular responses. Mutant p53 associates with the MSP gene promoter and represses its transcriptional activity, leading to a decrease in mRNA levels and a subsequent decrease in the levels of secreted MSP protein. Forced downregulation of MSP expression in H1299 cells, derived from a large-cell lung carcinoma, confers increased resistance against etoposide-induced cell death. These antiapoptotic consequences of MSP downregulation seemingly conflict with the well-documented ability of the RON receptor to promote cell survival and tumor progression when aberrantly hyperactive. Yet, they are consistent with the fact that reduced MSP expression was observed in many types of human cancer, including large-cell lung carcinoma. Thus, repression of MSP gene expression by mutant p53 may contribute to oncogenesis in a cell type-specific manner.

WHO/EORTC classification of cutaneous lymphomas 2005: histological and molecular aspects

The new WHO/EORTC classification for cutaneous lymphomas comprises mature T-cell and natural killer (NK)-cell neoplasms, mature B-cell neoplasms, and immature hematopoietic malignancies. It reflects the unique features of lymphoproliferative diseases of the skin, and at the same time it is as compatible as possible with the concepts underlying the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. This article reviews the histological, phenotypical, and molecular genetic features of the various nosological entities included in this new classification. These findings always have to be interpreted in the context of the clinical features and biologic behavior.

AIM

To review the histological, phenotypical and molecular genetic features of the various nosological entities of the new WHO/EORTC classification for cutaneous lymphomas.

METHODS

Extensive review of the literature cited in Medline and own data of the authors.

RESULTS

The WHO/EORTC classification of cutaneous lymphomas comprises mature T-cell and NK-cell neoplasms, mature B-cell neoplasms and immature hematopoietic malignancies. It reflects the unique features of primary cutaneous lymphoproliferative diseases.

CONCLUSION

This classification is as much as possible compatible with the concept of the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. The histological, phenotypical and molecular genetic features always have to be interpreted in the context of the clinical features and biologic behavior.

Comparative genomic hybridization analysis of cutaneous large B-cell lymphomas

The aim of the present study was to identify genetic aberrations in a series of patients with cutaneous large B-cell lymphoma (LBCL) using comparative genomic hybridization (CGH). Eighteen consecutive patients with primary (13 patients) (PCLBCL) and secondary (five patients) (SCLBCL) cutaneous large B-cell lymphoma were included in the study. Nine cases corresponded to PCLBCL leg type and four cases primary cutaneous follicle centre-cell lymphoma (PCFCL). Chromosomal imbalances (CIs) were detected in 14 of 18 samples (77.8%). All of nine cases with PCLBCL leg type and two of four cases with PCFCL showed CIs (100% and 50%, respectively). Regarding SCLBCL, in three of five cases (60%), CIs were detected. The most frequently detected gains involved 2q, 5q, 3 and 7q and amplifications affected 18, 12 and 13. Frequent losses were found in 17p. In PCLBCL leg type, the most frequent gains involved 2q and 7q, amplifications were localized in chromosomes 12, 13 and 18 and losses affected chromosomes 17p and 19. In PCFCL, gains located in 3q, 4 and 7q were found. Our study seems to confirm clear-cut differences between primary cutaneous LBCL and nodal diffuse LBCL, and it suggests the presence of genotypic differences between cases of PCLBCL leg type and cases of PCFCL.

Learning more from microarrays: insights from modules and networks

Global gene expression patterns can provide comprehensive molecular portraits of biologic diversity and complex disease states, but understanding the physiologic meaning and genetic basis of the myriad gene expression changes have been a challenge. Several new analytic strategies have now been developed to improve the interpretation of microarray data. Because genes work together in groups to carry out specific functions, defining the unit of analysis by coherent changes in biologically meaningful sets of genes, termed modules, improves our understanding of the biological processes underlying the gene expression changes. The gene module approach has been used in exploratory discovery of defective oxidative phosphorylation in diabetes mellitus and also has allowed definitive hypothesis testing on a genomic scale for the relationship between wound healing and cancer and for the oncogenic mechanism of cyclin D. To understand the genetic basis of global gene expression patterns, computational modeling of regulatory networks can highlight key regulators of the gene expression changes, and many of these predictions can now be experimentally validated using global chromatin-immunoprecipitation analysis.

Primary cutaneous large B-cell lymphomas: clinicopathologic features, classification, and prognostic factors in a large series of patients

In the new World Health Organization/European Organization for Research and Treatment of Cancer (WHO/EORTC) classification of cutaneous lymphomas, large B-cell lymphomas (LBCLs) are divided into 3 groups: LBCL, leg-type (LBCLLT); follicle center lymphoma, diffuse type (FCLDT); and LBCL, others (LBCLO). We studied a large number of primary cutaneous LBCLs to test the validity of the classification and to identify prognostic factors for these patients. Ninety-three cases of primary cutaneous LBCL were analyzed for clinicopathologic features, expression of several markers including Bcl-2, Bcl-6, MUM-1, and FOX-P1, in situ hybridization for Epstein-Barr virus, and molecular analyses of IGH gene rearrangement and of Borrelia burgdorferi and human herpesvirus 8 DNA. Patients were classified into the following categories: FCLDT, 44 cases; LBCLLT, 40 cases; and LBCLO, 9 cases. Statistical analyses showed that the LBCLLT and FCLDT groups were clearly distinct in terms of clinicopathologic features and survival. The LBCLO group had features in between those of LBCLLT and FCLDT. Our study shows that accurate morphologic and phenotypic analyses allow us to stratify most patients into the prognostically different categories of LBCLLT and FCLDT. The definition of a third category of LBCLO requires further studies to clarify whether these cases indeed show distinct clinicopathologic features.

BCL2 and JUNB abnormalities in primary cutaneous lymphomas

BACKGROUND

BCL2 is upregulated in nodal and extranodal B-cell non-Hodgkin's lymphomas, with a consequent antiapoptotic effect. However, loss of BCL2 has also been noted in some malignancies, suggesting a different molecular pathogenesis.

OBJECTIVES

To investigate genomic and protein expression status of BCL2 and to compare the results with that of JUNB in primary cutaneous lymphomas (PCLs).

METHODS

We analysed gene copy number of BCL2 and JUNB in 88 DNA samples from 80 patients with PCL consisting of Sézary syndrome/mycosis fungoides (SS/MF), primary cutaneous B-cell lymphoma (PCBCL) and primary cutaneous CD30+ anaplastic large cell lymphoma (C-ALCL) by the use of real-time polymerase chain reaction (PCR) and immunohistochemistry (IHC). Real-time PCR and IHC findings were subsequently compared with the results of additional fluorescent in situ hybridization (FISH) analysis of 23 cases of SS and Affymetrix cDNA expression microarray study of two primary cutaneous T-cell lymphoma (CTCL) cell lines.

RESULTS

Real-time PCR analysis showed loss of BCL2 gene copy number in 22 of 80 PCL cases (28%), including 17 of 42 SS/MF, three of 13 C-ALCL and two of 33 PCBCL samples, and gain of BCL2 in four PCBCL samples. Gain of JUNB was identified in 18 of 71 PCL cases (25%), including nine of 35 SS/MF, seven of 13 C-ALCL and two of 31 PCBCL samples. IHC analysis revealed absent nuclear expression of BCL2 protein in 47 of 73 PCL cases, comprising 28 of 36 SS/MF, eight of eight C-ALCL and 11 of 29 PCBCL cases. In contrast, BCL2 protein expression was detected in 26 of 73 PCL cases, consisting of 18 of 29 PCBCL and eight of 36 SS/MF cases. JUNB protein expression was present in tumour cells from 30 of 33 of SS/MF and eight of eight C-ALCL, and was absent in tumour cells from 18 of 27 PCBCL cases. A comparison between BCL2 and JUNB revealed loss of BCL2 and gain of JUNB in five of 35 SS/MF samples, and expression of JUNB protein and absent BCL2 expression in 25 SS/MF and eight of eight C-ALCL cases. In contrast, expression of BCL2 and absent JUNB expression were detected in 67% of PCBCL cases. Additional FISH analysis revealed deletion of BCL2 in 19 of 23 SS cases (83%), including eight cases with BCL2 loss shown by real-time PCR. Furthermore, Affymetrix expression microarray demonstrated decreased expression of proapoptotic and antiapoptotic genes involved in BCL2 signalling pathways such as BOK, BIM, HRK, RASA1 and STAT2 in two CTCL cell lines with BCL2 loss and absent BCL2 expression. Increased expression of JUNB was also identified in the MF cell line.

CONCLUSIONS

These findings provide a comprehensive assessment of BCL2 and JUNB status in PCL, and suggest that there is a selection pressure in a subset of CTCL cases for tumour cells showing BCL2 loss and upregulation of JUNB primarily through chromosomal deletion and amplification, respectively.

Pathology of Primary Cutaneous B-Cell Lymphomas: Diagnosis and Classification

The skin is the second most common extranodal site for non-Hodgkin's lymphomas. Therefore, hematologists, pathologists, and dermatologists need to be familiar with these lymphomas. Primary cutaneous B-cell lymphomas are less common than T-cell lymphomas but have received much attention in the past few years. Their typical clinical and pathologic features are becoming clear. However, there is still some disagreement in terminology and characteristics of these lymphomas between the World Heath Organization (WHO) classification and the European Organisation for Research and Treatment of Cancer (EORTC) proposal for primary cutaneous lymphomas. This review will focus on the features of primary cutaneous B-cell lymphomas, compare and contrast areas of discordance between the WHO and EORTC systems, and outline areas for further investigation.

Neoplastic cells do not carry bcl2-JH rearrangements detected in a subset of primary cutaneous follicle center B-cell lymphomas

Whether primary cutaneous follicular lymphoma (PCFL) may or not represent a cutaneous equivalent to nodal follicular lymphoma (FL) is not determined. We have therefore investigated a series of PCFL to determine if tumoral cells carry or not the t(14;18)(q32;q21) translocation, a cytogenetic hallmark of nodal FL. Thirty cases of PFCL were selected according to the criteria of both the European Organisation for Research and Treatment of Cancer and the World Health Organization with 21 cases classified as grade 1 or 2 and 9 cases as grade 3. First, cutaneous tumors were studied by PCR for the amplification of bcl-2/JH rearrangements and by interphase fluorescence in situ hybridization using a dual color probe spanning t(14;18) breakpoints. Second, we tried to determine the origin of bcl2-JH-positive cells by a parallel bcl2-JH and immunoglobulin heavy chain gene amplification of blood mononuclear cells DNA and of DNA extracted from single microdissected B cells. Bcl2-JH rearrangements were amplified by PCR in skin of 9 of 30 (30%) patients with a similar-sized bcl2-JH rearrangement detected in the blood of 7 of these 9 cases. No t(14;18) breakpoint was detected by interphase fluorescence in situ hybridization analysis of 11 bcl2-JH-negative and 5 bcl2-JH-positive PCFL in contrast with its detection in the secondary cutaneous FL and in the nodal FL cases. Single-cell/multigene analysis showed that no single monoclonal B cells of PCFL carried the bcl2-JH rearrangement. Bystander or nontumoral t(14;18)+ B cells emigrating from blood may account for the detection of bcl2-JH rearrangements within PCFL material. Our study also underlines the diagnostic value of interphase fluorescence in situ hybridization to discriminate between t(14;18)-negative PCFL and extracutaneous FL involving the skin.

Diagnostic principles and new developments in primary cutaneous B-cell lymphomas

The most common subtypes of primary cutaneous B-cell lymphomas are marginal zone B-cell lymphoma/immunocytoma, follicle center cell lymphoma, and large B-cell lymphoma of the leg. Precise classification (European Organization for Research and Treatment of Cancer (EORTC) scheme) can be achieved only after a complete synthesis of clinical, histopathological, immunophenotypic, and molecular features. It is extremely important to emphasize that primary cutaneous B-cell lymphomas differ significantly from their nodal counterparts and are frequently characterized by an excellent prognosis. Awareness of this special clinical behavior should prevent the application of unnecessarily aggressive treatment protocols. Future definitions of primary cutaneous B-cell lymphomas will be based on their etiology and pathogenesis and especially on their molecular features. Some important areas are presented where exciting findings have been detected.

Primary Cutaneous B-Cell Lymphoma Treated With Radiotherapy: A Comparison of the European Organization for Research and Treatment of Cancer and the WHO Classification Systems

Purpose

To determine the relationship between the WHO and European Organization for Research and Treatment of Cancer (EORTC) pathologic classifications for primary cutaneous B-cell lymphoma (CBCL) and the implication of this relationship on initial treatment.

Patients and Methods

Patients with primary CBCL treated with radiotherapy were identified retrospectively. Initial biopsy specimens were reviewed by two dermatopathologists and classified according to the EORTC and WHO systems. Primary outcomes were recurrence-free and overall survival.

Results

Thirty-four patients were identified; initial biopsy specimens were adequate for classification in 32 patients. Four different composite histopathologic subtypes of lymphoma were identified: 53% (17 of 32) follicle center cell by EORTC and diffuse large B-cell by WHO (FCC/DLB), 25% (eight of 32) follicle center cell by EORTC and follicular by WHO (FCC/Fol), 13% (four of 32) marginal zone by EORTC and WHO (MZ/MZ), and 9% (three of 32) large B-cell of the leg by EORTC and diffuse large B-cell by WHO (Leg/DLB). Five-year relapse-free survival ranged from 62% to 73% for FCC/DLB, FCC/Fol, and MZ/MZ but was 33% for Leg/DLB (P = .6). Five-year overall survival was 100% for FCC/DLB, FCC/Fol, and MZ/MZ but was 67% for Leg/DLB (P = .07). At 5 years, 21% of all patients had developed extracutaneous disease.

Conclusion

Two-thirds of primary cutaneous FCC lymphomas by EORTC criteria satisfy WHO criteria for DLB lymphoma. Unlike DLB lymphoma presenting in nodal or noncutaneous sites, these lesions are associated with an indolent course and may be treated with local radiotherapy alone.