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In breast cancer the human epidermal growth factor receptor 2 (HER2) is an important target for a number of different HER2 inhibitors. Different slide-based assays are available for assessment of treatment eligibility, which include fluorescence in situ hybridization (FISH) or other in situ hybridization (ISH) methods for assessment of the HER2 gene status. Here we report a summary of the validation data on HER2 IQFISH pharmDx™ (Dako Omnis), a newly developed assay for the automated staining platform Dako Omnis. The assay uses a non-toxic buffer that significantly reduces the hybridization time, which results in a total turnaround time of 3½ to 4h from deparaffinization to counting of the gene and centromere signals. The data reported in the current summary covers method comparison, assessment of staining quality, observer-to-observer reproducibility as well as reproducibility within and between laboratories. Based on data from the different studies it was concluded that HER2 IQFISH pharmDx (Dako Omnis) is a reliable and robust assay with a high precision that is at least comparable to the manual HER2 IQFISH pharmDx™ assay and the PathVysion® HER-2 DNA Probe Kit.

Background: This is a feasibility study to determine whether circulating tumour cells (CTCs) are detectable and suitable for molecular profiling in advanced endometrial cancer (aEC). Method: Between October 2012 and February 2014, 30 patients with aEC had baseline and up to 3 follow-up samples. CTCs and stathmin expression were evaluated using the CellSearch platform. Epithelial cell adhesion molecule (EpCAM) and stathmin immunohistochemistry were performed on FFPE tumour tissue. Results: Eighteen from 30 (60%) patients had detectable CTCs during study [1 CTC (n = 7), 2 (n = 4), 3 (n = 1), 4 (n = 2), 7 (n = 1), 8 (n = 1), 22 (n = 1), 172 (n = 1) in 7.5 ml blood]. Ten from 18 patients had between 50 and 100% of detectable CTCs that were stathmin positive. More CTC-positive than CTC-negative patients had non-endometrioid versus endometrioid histology, tumour size ≥5 versus 0.05, 95% confidence interval 0.7-16.2]. Twenty-one tumour blocks were tested for EpCAM and stathmin immunohistochemistry (IHC). Stathmin tumour immunostaining scores (TIS) on IHC were higher in CTC-positive patients. Conclusion: CTC enumeration and molecular profiling with stathmin on the CellSearch platform is feasible in aEC. Stathmin TIS on IHC, a known prognostic marker in EC, was associated with CTC positivity.

MS-based proteomic methods were utilised for the first time in the discovery of novel penile cancer biomarkers. MALDI MS imaging was used to obtain the in situ biomolecular MS profile of squamous cell carcinoma of the penis which was then compared to benign epithelial MS profiles. Spectra from cancerous and benign tissue areas were examined to identify MS peaks that best distinguished normal epithelial cells from invasive squamous epithelial cells, providing crucial evidence to suggest S100A4 to be differentially expressed. Verification by immunohistochemistry resulted in positive staining for S100A4 in a sub-population of invasive but not benign epithelial cells.

Summary Lymphoid enhancer-binding factor 1 (LEF1) is a neutrophilic granulopoiesis regulator whose absence is critical in congenital neutropenia. We have shown LEF1 downregulation in the CD34+ cells of the majority of myelodysplastic syndromes (MDS) patients. LEF1 was the most significant differentially expressed gene between early and advanced MDS. Marked LEF1 downregulation was found in 27/32 patients with advanced MDS and in 6/35 patients with early MDS, and was associated with neutropenia. Downregulation of LEF1 mRNA was reflected at the protein level. Immunostaining for CD34/LEF1 may represent a marker of advanced MDS. LEF1 may play a role in the defective maturation of myeloid progenitors in MDS.

AIMS: We describe a new rabbit monoclonal antibody, raised against a fixation-resistant epitope of the transcription regulator LIM domain only 2 (LMO2). METHODS AND RESULTS: Lymphoma cell lines and a large series of normal and neoplastic samples were investigated by Western blot and immunohistochemistry. The antibody detected nuclear positivity for the protein, with the exception of a proportion of classical Hodgkin lymphomas (HLs), peripheral T cell lymphomas (PTCLs) and solid tumours that showed granular cytoplasmic staining. In normal lympho-haematopoietic tissues, LMO2 was expressed at different intensities by CD34(+) blasts, haematopoietic precursors, germinal centre (GC), mantle and splenic marginal zone B cells. While reactive with only scattered elements in the thymus and nine of 237 PTCLs, the antibody stained 31 of 39 T-acute lymphoblastic lymphoma/leukaemias (T-ALLs) and the T-ALL-derived human leukaemic cell line, CCRF-CEM. LMO2 was found in 88% of B-acute lymphoblastic lymphoma/leukaemias (B-ALLs), 5% chronic lymphocytic leukaemias (CLLs) and 14%, 57% and 41% of mantle, follicular and Burkitt lymphomas, respectively. In the setting of diffuse large B cell lymphomas (DLBCLs), LMO2-positivity was related strongly to a GC phenotype. LMO2 was found in 83% primary mediastinal large B cell lymphomas (PMBLs) and 100% nodular lymphocyte predominant Hodgkin lymphomas (NLPHLs), whereas only 10% of classical HLs were stained. Acute and chronic myeloid leukaemias were usually positive. CONCLUSIONS: The new anti-LMO2 antibody can be applied confidently to routine sections, contributing to the differential diagnosis of several lymphoma subtypes, subtyping of DLBCLs and potential development of innovative therapies.

B-cell maturation antigen (BCMA, also termed TNFRSF17) is an attractive therapeutic target due to its restricted expression on normal and malignant plasma cells (PC). GSK2857916 (or J6M0-MMAF) is a BCMA-specific antibody conjugated to the microtubule-disrupting agent monomethyl auristatin F (MMAF) via a protease-resistant linker. To evaluate the clinical potential of this agent, tumour cells from seventy multiple myeloma (MM) patients were assessed for BCMA expression by immunohistochemistry and flow cytometry. All patients tested expressed BCMA, at varying levels, and both surface and intracellular expression were observed. BCMA expression is maintained through relapse, extramedullary spread and in residual disease post therapy. BCMA levels may also be prognostically useful as higher levels of BCMA were associated with poorer outcomes, even taking into account genetic risk. We observed rapid internalization of surface BCMA and newly expressed protein by 1 h, suggesting a mechanism for J6M0-MMAF activity even with low surface antigen. J6M0-MMAF mediated cytotoxicity of MM cells varied with dose and antigen levels, with clonogenic progenitors killed at lower doses than mature cells. In comparison, J6M0-MMAF killing of primary CD138(+) myeloma cells occurred with slower kinetics. Our observations support BCMA to be a promising therapeutic target in MM for novel therapies such as J6M0-MMAF.

Angioimmunoblastic T-cell lymphoma (AITL) is the most frequent nodal T-cell lymphoma and is characterized by a polymorphic lymph node infiltrate, various dysimmune disorders, and a poor prognosis. Regulatory T-cells (Treg) play an emerging role in the prognosis of non-Hodgkin B-cell lymphoma and mediate significant autoreactive T-cell suppression. In this report, we demonstrate that numbers of Treg are significantly decreased in AITL lymph nodes [n = 30, 91 (40-195) per high power fields] compared with follicular lymphoma [n = 19, 179 (86-355)] and reactive lymph nodes [n = 8, 186 (140-265)]. Moreover, the few Treg in lymph nodes of AITL are resting Treg (rTreg) and have a naive CD45RA+, PD1-, and ICOS- phenotype [n = 5, 57% of Treg are CD45RA+ (16-96)], in contrast to the Treg in follicular lymphomas [n = 5, 7.4% (1-13)] or reactive lymph nodes [n = 7, 18.6% (6-48)]. Interestingly, Treg depletion was not observed in AITL peripheral blood at diagnosis. Altogether, these data suggest that Treg depletion could contribute to the nodal neoplastic T(FH) expansion and dysimmune symptoms in AITL.

Focal adhesion kinase (FAK) is a protein tyrosine kinase essential for intracellular regulatory events, such as cell growth, differentiation, migration and tumor metastasis. The aim of this study was to analyze the expression of FAK protein in a series of normal and neoplastic lymphoid tissues. An anti-FAK antibody was used to study the protein expression in paraffin-embedded samples of normal and neoplastic, hematolymphoid and non-hematolymphoid tissues by immunohistochemistry. In normal hematolymphoid tissue, the strongest expression of FAK was detected in germinal center and marginal-zone B cells; positive staining was also found in mantle zone B cells. In human lymphomas, FAK was expressed mostly in B-cell lymphomas and was predominantly negative in T-cell lymphoma. In Hodgkin lymphomas, FAK was found only in the neoplastic cells of lymphocyte predominant type, whereas the tumor cells of the classical form were FAK-negative. We demonstrate for the first time the expression of FAK in paraffin-embedded hematolymphoid tissue samples. Its differential expression in lymphomas may be of relevance for some B-cell neoplasms by using it as an additional marker to distinguish B- from T-lymphoblastic leukemia/lymphoma to further differentiate lymphocyte predominant from classical Hodgkin lymphoma.

c-Maf, a leucine zipper-containing transcription factor, is involved in the t(14;16)(q32;q23) translocation found in 5% of myelomas. A causal role for c-Maf in myeloma pathogenesis has been proposed, but data on c-Maf protein expression are lacking. We therefore studied the expression of c-Maf protein by immunohistochemical analysis in myelomas and in a wide variety of hematopoietic tissue. c-Maf protein was detected in a small minority (4.3%) of myelomas, including a t(14;16)(q32;q22-23)/IgH-Maf+ case, suggesting that c-Maf protein is not expressed in the absence of c-Maf rearrangement. In contrast, c-Maf was strongly expressed in hairy cell leukemia (4/4) and in a significant proportion of T-cell (24/42 [57%]) and NK/T-cell (49/97 [51%]) lymphomas, which is in keeping with prior gene expression profiling and transgenic mouse studies. Up-regulation of c-Maf protein occurs in a small subset of myelomas, in hairy cell leukemia, and in T- and NK-cell neoplasms. Its detection may be of particular value in the differential diagnosis of small cell lymphomas.

The neoplastic Reed-Sternberg cells characteristic of classical Hodgkin's lymphoma (cHL) are of B-cell origin but they almost always show striking loss of a range of B-cell-associated molecules. In contrast, the neoplastic cells found in lymphocyte predominant Hodgkin's lymphoma (LPHL) (L&H cells) are traditionally thought of as possessing the full repertoire of features associated with germinal centre B cells (eg BCL-6 expression, 'ongoing' Ig gene mutation). In the present paper, we report an extensive phenotypic analysis of L&H cells which revealed down-regulation of a number of markers associated with the B-cell lineage (eg CD19, CD37) and with the germinal centre maturation stage (eg PAG, LCK). The promoter methylation status of three of these down-regulated genes (CD10, CD19, and LCK) was further studied in microdissected L&H cells, and this revealed that their promoters were unmethylated. In contrast, these genes showed promoter methylation in cell lines derived from CHL. Further investigation of the mechanisms responsible for the deregulation of these molecules in L&H cells may provide new insights into the genetic abnormalities underlying LPHL. Copyright (c) 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Jaw1, also known as lymphoid-restricted membrane protein (LRMP), is an endoplasmic reticulum-associated protein. High levels of Jaw1/LRMP mRNA have been found in germinal centre B-cells and in diffuse large B-cell lymphomas of 'germinal centre' subtype. This paper documents Jaw1/LRMP expression at the protein level in human tissues by immunohistochemical and western blotting analysis using an antibody reactive with paraffin-embedded tissues. Jaw1/LRMP was highly expressed in germinal centre B-cells (in keeping with gene expression data), in 'monocytoid B-cells', and in splenic marginal zone B-cells. It was absent, or present at only low levels, in mature T-cells, although cortical thymocytes were weakly positive. Among lymphoid neoplasms, Jaw1/LRMP was found in germinal centre-derived lymphomas (follicle centre lymphoma, Burkitt's lymphoma, lymphocyte-predominant Hodgkin's disease) but not in T-cell neoplasms (with the exception of a single T lymphoblastic lymphoma). Classical Hodgkin's disease and myeloma lacked Jaw1/LRMP but many cases of chronic lymphocytic leukaemia (but not mantle zone lymphoma) were Jaw1/LRMP-positive. Approximately half of the marginal zone lymphomas were Jaw1/LRMP-positive. In diffuse large B-cell lymphomas, Jaw1/LRMP was found in three-quarters (24/32) of the cases classified phenotypically as being of 'germinal centre' type, but it was also expressed in almost half (13/28) of the 'non-germinal centre' cases. A similar proportion of 'non-germinal centre' cases were positive for the protein products of two other genes expressed highly in germinal centre cells (HGAL/GCET2 and PAG). The fact that all three of these proteins are expressed in a significant proportion of diffuse large B-cell lymphomas assigned to the 'non-germinal centre' category indicates that the immunophenotypic categorization of diffuse large B-cell lymphoma according to cellular origin may be more complicated than currently understood. Finally, the expression of Jaw1/LRMP in other types of lymphoma and in non-lymphoid tissues/tumours may be of interest in differential diagnosis and research.

Aims: The aim of this study was to analyse the immunophenotypic and molecular features of a large series of follicular lymphomas, focusing in particular on atypical cases that fail to express CD10 and/or bcl-2. Such cases present diagnostic pitfalls, especially with regard to the differential diagnosis from follicular hyperplasia and marginal zone B-cell lymphoma. Therefore, we also included an immunohistochemical evaluation of stathmin, which is strongly expressed by germinal centre B cells, as a putative new marker for follicular lymphomas, particularly those with an atypical phenotype. Methods and results: Two hundred and five follicular lymphomas were investigated with immunohistochemistry and fluorescence in-situ hybridization (FISH). The use of three distinct anti-bcl-2 antibodies together with CD10 expression data and FISH analysis for bcl-2 and bcl-6 rearrangements allowed subclassification of follicular lymphoma into four distinct subgroups: (i) CD10-positive/bcl-2-positive, (ii) CD10-positive/bcl-2-negative, (iii) CD10-negative/bcl-2-positive, and (iv) CD10-negative/bcl-2-negative. All cases were bcl-6-positive. STMN1 (stathmin) was shown to be helpful in diagnosing bcl-2-negative and/or CD10-negative follicular lymphomas, and in their distinction from marginal zone B-cell lymphoma. Conclusions: Combined immunohistological and molecular analyses reveal that follicular lymphomas showing an atypical immunophenotypic and molecular profile exist, and we demonstrate that STMN1 represents a novel useful diagnostic marker for these. © 2013 Blackwell Publishing Ltd.

In this article, we report that cutaneous T cell lymphoma (CTCL) cells and tissues ubiquitously express the immunosuppressive cell surface protein CD80 (B7-1). CD80 expression in CTCL cells is strictly dependent on the expression of both members of the STAT5 family, STAT5a and STAT5b, as well as their joint ability to transcriptionally activate the CD80 gene. In IL-2–dependent CTCL cells, CD80 expression is induced by the cytokine in a Jak1/3- and STAT5a/b-dependent manner, whereas in the CTCL cells with constitutive STAT5 activation, CD80 expression is also STAT5a/b dependent but is independent of Jak activity. Although depletion of CD80 expression does not affect the proliferation rate and viability of CTCL cells, induced expression of the cell-inhibitory receptor of CD80, CD152 (CTLA-4), impairs growth of the cells. Coculture of CTCL cells with normal T lymphocytes consisting of both CD4+ and CD8+ populations or the CD4+ subset alone, transfected with CD152 mRNA, inhibits proliferation of normal T cells in a CD152- and CD80-dependent manner. These data identify a new mechanism of immune evasion in CTCL and suggest that the CD80–CD152 axis may become a therapeutic target in this type of lymphoma.

Aims: Marginal zone B cells (MZCs) and monocytoid B cells (MBCs) appear to be related lymphoid cells that take part in reactive and neoplastic marginal zone proliferations. These lesions are not yet well characterized, and the aim of this study was to find better diagnostic criteria for them. Methods and results: We analysed 60 nodal lesions with MBC and/or MZC proliferation for their morphological, immunophenotypic, molecular genetic and IG gene rearrangement features. On the basis of the results of the rearrangement assay and immunoglobulin light chain restriction, the lesions were divided into reactive and neoplastic groups. Among the neoplastic lesions, polymorphic and monomorphic subgroups emerged. All reactive lesions had morphological features of the polymorphic subgroup. By immunohistochemistry, IRTA1 and/or T-bet expression was found in all reactive lesions and in 90% of neoplastic lesions. Conclusions: IRTA1 and T-bet are positive markers for the identification of MZC/MBC proliferations, and thus for the diagnosis of nodal marginal zone lymphoma (NMZL). Polymorphic and monomorphic subgroups of NMZL could be distinguished. Most morphological and immunophenotypic patterns in reactive and neoplastic nodal expansions of MZCs and MBCs overlapped. Therefore, PCR clonality assay of the immunoglobulin heavy and light chain gene loci is the most reliable method for their differentiation. © 2013 John Wiley & Sons Ltd.

We describe a new rabbit monoclonal antibody, raised against a fixation-resistant epitope of the transcription regulator LIM domain only 2 (LMO2).Lymphoma cell lines and a large series of normal and neoplastic samples were investigated by Western blot and immunohistochemistry. The antibody detected nuclear positivity for the protein, with the exception of a proportion of classical Hodgkin lymphomas (HLs), peripheral T cell lymphomas (PTCLs) and solid tumours that showed granular cytoplasmic staining. In normal lympho-haematopoietic tissues, LMO2 was expressed at different intensities by CD34(+) blasts, haematopoietic precursors, germinal centre (GC), mantle and splenic marginal zone B cells. While reactive with only scattered elements in the thymus and nine of 237 PTCLs, the antibody stained 31 of 39 T-acute lymphoblastic lymphoma/leukaemias (T-ALLs) and the T-ALL-derived human leukaemic cell line, CCRF-CEM. LMO2 was found in 88% of B-acute lymphoblastic lymphoma/leukaemias (B-ALLs), 5% chronic lymphocytic leukaemias (CLLs) and 14%, 57% and 41% of mantle, follicular and Burkitt lymphomas, respectively. In the setting of diffuse large B cell lymphomas (DLBCLs), LMO2-positivity was related strongly to a GC phenotype. LMO2 was found in 83% primary mediastinal large B cell lymphomas (PMBLs) and 100% nodular lymphocyte predominant Hodgkin lymphomas (NLPHLs), whereas only 10% of classical HLs were stained. Acute and chronic myeloid leukaemias were usually positive.The new anti-LMO2 antibody can be applied confidently to routine sections, contributing to the differential diagnosis of several lymphoma subtypes, subtyping of DLBCLs and potential development of innovative therapies.

Here we report that T-cell lymphoma cells carrying the NPM-ALK fusion protein (ALK+ TCL) frequently express the cell-stimulatory receptor ICOS. ICOS expression in ALK+ TCL is moderate and strictly dependent on the expression and enzymatic activity of NPM-ALK. NPM-ALK induces ICOS expression via STAT3, which triggers the transcriptional activity of the ICOS gene promoter. In addition, STAT3 suppresses the expression of miR-219 that, in turn, selectively inhibits ICOS expression. ALK+ TCL cell lines display extensive DNA methylation of the CpG island located within intron 1, the putative enhancer region, of the ICOS gene, whereas cutaneous T-cell lymphoma cell lines, which strongly express ICOS, show no methylation of the island. Treatment of the ALK+ TCL cell lines with DNA methyltransferase inhibitor reversed the CpG island methylation and augmented the expression of ICOS mRNA and protein. Stimulation of the ICOS receptor with anti-ICOS antibody or ICOS ligand-expressing B cells markedly enhanced proliferation of the ALK+ TCL cells. These results demonstrate that NPM-ALK, acting through STAT3 as the gene transcriptional activator, induces the expression of ICOS, a cell growth promoting receptor. These data also show that the DNA methylation status of the intronic CpG island affects transcriptional activity of the ICOS gene and, consequently, modulates the concentration of the expressed ICOS protein.

Background During B-cell development, precursor B cells transiently express the pre-B-cell receptor composed of μ heavy chain complexed with VpreB and λ5 surrogate light chain polypeptides. Recent profiling studies unexpectedly revealed abundant transcripts of one member of the VpreB family, VpreB3, in a subset of mature B cells and Burkitt lymphoma. Design and Methods Here we used a novel antibody to investigate the normal expression pattern of VpreB3 protein in human hematopoietic and lymphoid tissues, and to determine whether VpreB3 could serve as a useful diagnostic biomarker for select B-cell lymphomas. Results We found that VpreB3 protein is normally expressed by precursor B cells in bone marrow and by a subset of normal germinal center B cells in secondary lymphoid organs. Among lymphoid malignancies, we found an association between VpreB3 expression and B-cell tumors with c-MYC abnormalities. VpreB3 was highly expressed in all cases of Burkitt lymphoma, whether of endemic or sporadic origin (44/44 cases, 100%), all cases of B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma (5/5 cases, 100%), and the majority of diffuse large B-cell lymphomas harboring a c-MYC translocation (15/18 cases, 83%). The expression of VpreB3 in diffuse large B-cell lymphomas without a c-MYC translocation was associated with c-MYC polysomy in 25/75 cases (33%) but only rarely observed in diffuse large B-cell lymphomas lacking a c-MYC abnormality (9/98 cases, 9%). Conclusions We conclude that for B-cell tumors with features suggesting a possible c-MYC translocation, such as intermediate to large cell size and high proliferation rate, the presence of VpreB3 should prompt subsequent confirmatory genetic testing, whereas the absence of VpreB3 is virtually always associated with wild-type c-MYC alleles.

To the editor: There is mounting evidence from the study of animal models of human disorders of defective ribosome biogenesis, including Diamond-Blackfan anemia and Treacher Collins syndrome, that ribosomal stress leads to activation of the p53 pathway.[1][1][⇓][2]–[3][3] Stabilization of p53

Double immunoenzymatic labeling of 2 different molecules in tissue sections is a widely used technique. However, it is time consuming since the 2 immunoenzymatic procedures are carried out in sequence, and they must also be optimally performed to avoid unwanted background labeling. In this paper, we report that double immunoenzymatic staining performed using automated immunostaining apparatus considerably reduces the requirements in terms of time and is also highly reproducible and free of background. Three tissue markers can also be visualized by performing (after immunoperoxidase labeling) 2 sequential immuno-alkaline phosphatase procedures using different substrates. Furthermore, single or double detection of mRNA by in situ hybridization can be combined with immunoenzymatic labeling. Finally, automated labeling could also be performed on peripheral blood and bone marrow smears, opening the possibility of using this procedure in the analysis of hematologic/cytology samples.

Plasmacytoid dendritic cells (pDCs) are involved in innate immunity (eg, by secreting interferons) and also give rise to CD4+CD56+ hematodermic neoplasms. We report extensive characterization of human pDCs in routine tissue samples, documenting the expression of 19 immunohistologic markers, including signaling molecules (eg, BLNK), transcription factors (eg, ICSBP/IRF8 and PU.1), and Toll-like receptors (TLR7, TLR9). Many of these molecules are expressed in other cell types (principally B cells), but the adaptor protein CD2AP was essentially restricted to pDCs, and is therefore a novel immunohistologic marker for use in tissue biopsies. We found little evidence for activation-associated morphologic or phenotypic changes in conditions where pDCs are greatly increased (eg, Kikuchi disease). Most of the molecules were retained in the majority of pDC neoplasms, and 3 (BCL11A, CD2AP, and ICSBP/IRF8) were also commonly negative in leukemia cutis (acute myeloid leukemia in the skin), a tumor that may mimic pDC neoplasia. In summary, we have documented a range of molecules (notably those associated with B cells) expressed by pDCs in tissues and peripheral blood (where pDCs were detectable in cytospins at a frequency of < 1% of mononuclear cells) and also defined potential new markers (in particular CD2AP) for the diagnosis of pDC tumors.

Diffuse large B cell lymphoma (DLBCL) is an aggressive malignancy that accounts for nearly 40% of all lymphoid tumors. This heterogeneous disease can be divided into germinal center B cell-like (GCB) and activated B cell-like (ABC) subtypes by gene expression and immunohistochemical profiling. Using microarray analysis on prototypic cell lines, we identified microRNAs (miR-155, miR-21 and miR-221) that were more highly expressed in ABC-type than GCB-type cell lines. These microRNAs were over-expressed in de novo DLBCL (n = 35), transformed DLBCL (n = 14) and follicular center lymphoma cases (n = 27) compared to normal B cells. Consistent with the cell line model, expression levels were higher in DLBCL cases with an ABC-type immunophenotype than those that were GCB-type (p < 0.05). Moreover, using multivariate analysis we found that expression of miR-21 was an independent prognostic indicator in de novo DLBCL (p < 0.05). Interestingly, expression levels of both miR-155 and miR-21 were also higher in nonmalignant ABC than in GCB cells. As we also demonstrate that expression of microRNAs can be measured reliably from routine paraffin-embedded biopsies of more than 8-years-old (p < 0.001), we suggest that microRNAs could be clinically useful molecular markers for DLBCL as well as other cancers.

The presumed involvement of paired box gene 5 (PAX5) in B-lymphomagenesis is based largely on the discovery of Pax5-specific translocations and somatic hypermutations in non-Hodgkin lymphomas. Yet mechanistically, the contribution of Pax5 to neoplastic growth remains undeciphered. Here we used 2 Myc-induced mouse B lymphoma cell lines, Myc5-M5 and Myc5-M12, which spontaneously silence Pax5. Reconstitution of these cells with Pax5-tamoxifen receptor fusion protein (Pax5ER(TAM)) increased neoplastic growth in a hormone-dependent manner. Conversely, expression of dominant-negative Pax5 in murine lymphomas and Pax5 knockdown in human lymphomas negatively affected cell expansion. Expression profiling revealed that Pax5 was required to maintain mRNA levels of several crucial components of B cell receptor (BCR) signaling, including CD79a, a protein with the immunoreceptor tyrosine-based activation motif (ITAM). In contrast, expression of 2 known ITAM antagonists, CD22 and PIR-B, was suppressed. The key role of BCR/ITAM signaling in Pax5-dependent lymphomagenesis was corroborated in Syk, an ITAM-associated tyrosine kinase. Moreover, we observed consistent expression of phosphorylated BLNK, an activated BCR adaptor protein, in human B cell lymphomas. Thus, stimulation of neoplastic growth by Pax5 occurs through BCR and is sensitive to genetic and pharmacological inhibitors of this pathway.

Background and Objectives In the present paper we report that SAP, an intracytoplasmic molecule that is involved in cell signaling, is an immunohistologic marker for germinal center T cells in paraffin-embedded tissue. We document its expression, and also that of PD-1 (another recently described marker of germinal center T cells to which a new antibody has been raised), in normal and neoplastic lymphoid tissue to evaluate the suggestion that helper T cells within the germinal centers of human lymphoid tissue are the cell of origin of angioimmunoblastic T-cell lymphoma (AITL), and to assess the diagnostic value of these two markers.Design and Methods Expression of SAP and PD-1 was investigated by immunohistochemistry in paraffin-embedded tissue sections and in cell lines. Western blotting was performed on cell lines, and antibody specificity was confirmed by immunostaining of transfected cells.Results Screening on more than 500 lymphoma biopsies showed that 95% (40/42) of cases of AITL expressed at least one of these markers. SAP was also expressed on many cases (15/21) of acute T lymphoblastic leukemia, in keeping with its presence in cortical thymocytes. However, PD-1 and SAP were also found in a minority of cases of peripheral T-cell lymphoma other than AITL, in contrast to a report that the former marker is specific for AITL. This observation raises the possibility that such non-angioimmunoblastic cases may be related to germinal center helper T cells.Interpretation and Conclusions These two markers provide additional evidence that AITL arises from germinal center T cells. They may also prove of value in the diagnosis of this disease since a negative reaction was rarely observed in this disorder.

We explored the expression of LCK and BAFF-R (B-cell activating factor receptor) both of which are known to play a role in signaling and apoptosis, in routine tissue biopsies. It was hypothesized that their expression patterns might yield information on apoptosis as it occurs in normal and reactive lymphoid cells, and also be of value for the detection of lymphoma subtypes.Both molecules were studied in paraffin-embedded tissue sections and cell lines by immunoperoxidase staining, and were also studied by western blotting. Human tonsillar B-cell subsets were analyzed by flow cytometry for LCK expression.LCK was detected for the first time in germinal centers and, at lower levels, in mantle zone B cells. The presence of LCK in B cells was confirmed by western blotting. Cross-linking surface IgM reduced LCK expression whereas cross-linking surface CD40 appeared to have the opposite effect. BAFF-R was present on mantle zone B cells but absent or weakly expressed in germinal center cells. Most lymphomas of germinal center origin (e.g. follicular lymphoma) and also many mantle cell lymphomas, chronic lymphocytic leukemia (CLL) and most T-cell neoplasms expressed LCK. In contrast, BAFF-R was expressed in a variety of B-cell lymphomas, but often absent in grade 3 follicular lymphomas and diffuse large B-cell lymphomas (DLBCL). Both LCK-positive and BAFF-R-positive DLBCL tended to be of germinal-center phenotype.The reciprocal expression pattern of LCK and BAFF-R in germinal center and mantle zone B cells may reflect their opposing roles in apoptosis. Their detection in lymphoma tissue biopsies may therefore be of clinical relevance in predicting response to treatment.

Transmembrane adaptor proteins (of which 7 have been identified so far) are involved in receptor signaling in immune cells. They have only a short extracellular region, with most of the molecule comprising a substantial intracytoplasmic region carrying multiple tyrosine residues that can be phosphorylated by Src- or Syk-family kinases. In this paper, we report an immunohistologic study of 6 of these molecules in normal and neoplastic human tissue sections and show that they are restricted to subpopulations of lymphoid cells, being present in either T cells (LAT, LIME, and TRIM), B cells (NTAL), or subsets of both cell types (PAG and SIT). Their expression in neoplastic lymphoid cells broadly reflects that of normal lymphoid tissue, including the positivity of plasma cells and myeloma/plasmacytoma for LIME, NTAL, PAG, and SIT. However, this study also revealed some reactions that may be of diagnostic/prognostic value. For example, lymphocytic lymphoma and mantle-cell lymphoma showed similar profiles but differed clearly from follicle-center lymphoma, whereas PAG tended to be selectively expressed in germinal center-derived subsets of diffuse large B-cell lymphoma. These molecules represent a potentially important addition to the panel of immunophenotypic markers detectable in routine biopsies that can be used in hematopathologic studies.

5600 Background: CTCs are prognostic and predictive markers in many solid tumours. There are no validated biomarkers to assess treatment (tx) response or molecular therapies in aEC. We conducted a ...

B-cell maturation antigen (BCMA) is upregulated at the terminal stages of plasma cell (PC) differentiation, and is expressed on normal and malignant PC. Apart from low levels of mRNA detected on dendritic cells, expression appears absent on other tissues, indicating the potential as a target for novel antibody therapeutics for multiple myeloma (MM). We generated a humanised anti-BCMA antibody, modified for Fc-enhanced function, and conjugated to mcMMAF (anti-BCMA antibody drug conjugate, ADC). Flow cytometric studies on human myeloma cell lines (HMCL) showed rapid internalisation of anti-BCMA antibody by flow cytometry and confocal microscopy. The internalised antibody was transported to the lysosome and was nearly undetectable by confocal microscopy after 6 hours, indicating the suitability of BCMA as a target for an antibody drug conjugate (ADC). BCMA expression reached original surface levels by 6 hours post antibody treatment, thus maintaining the cell as a target for effector mediated killing. Evaluation of BCMA expression on HMCL revealed variable surface expression (1/11 high, 5/11 moderate, 5/11 low). Tumour cell killing by the ADC was expression level, dose and time dependent. The highest expressing HMCL, H929, showed significant killing (60% at 100ng/mL) at 24 hours, and up to 90% after 2 days. Cells expressing moderate levels of BCMA required incubation for up to 4 days to show maximal levels of cell death, suggesting the importance of continued internalisation of the antibody/antigen complexes over this period. ARH77 cells were transduced to express varying levels of BCMA, and killing at 3 days (200ng/ml) was directly proportional to level of surface expression (NT 0% killing, Low BCMA 75% killing, High BCMA 90%). We studied surface antigen levels in a cohort of patients to ascertain the need for patient selection. Like the HMCL, patient CD138+ plasma cells (PC) displayed a range of expression. Of 67 patients tested, CD138+ PC from 12 expressed high levels, 52 expressed intermediate, and 3 had low/negative surface BCMA as determined by MFI ratio of specific antibody to isotype control. Non-CD138+ cells from the bone marrow (BM) were negative for BCMA. Immuno-histochemistry (IHC) on paraffin-embedded BM sections, using a murine antibody and dual staining with anti-Blimp1 to identify tumour cells, revealed both membrane and diffuse, or punctate, cytoplasmic staining. Expression levels varied, from high uniform, to heterogeneous and patchy, to uniform low level. In no patient were the tumour cells entirely negative for BCMA. There was broad correlation between FACS analysis and IHC, thus patients were divided into high, moderate and low expressing groups. Examination of patient and disease characteristics revealed no correlation between BCMA expression and disease stage, response to last treatment, time from diagnosis, isotype, CD56 expression, or cyclin D-type, but there was a trend towards higher BCMA levels in tumours with adverse genetics (90% of patients with adverse genetics had high/moderate levels cf 64% of patients with standard CGN (p=0.06, Fisher’s exact test, 2-tailed). CD138+ cells in LPL (n=3) were positive for BCMA, but CD20+ lymphocytes were negative. Serum BCMA levels in MM patients (175.6±242.6ng/mL; mean±SD, n=34) were higher than in normal subjects (9.28±1.9ng/mL; n=38) but no correlation with bone marrow plasmacytosis or surface BCMA was noted. Levels appeared similar between new diagnosis (147.6±190.8ng/mL; mean±SD, n=8) and relapsed disease (184.3±259.1ng/mL; n=26). We tested ADC activity on primary tumour cells in whole BM cultures, enumerating viable CD138+ cells by flow cytometry. As with the HMCL, ADC mediated cytotoxicity was expression level, dose and time dependent, with a slower time course than with HMCL, perhaps reflecting the slower turn-over of these cells. In samples expressing moderate levels of BCMA, ADC-mediated cytotoxicity increased from 23.1±2.9% (mean±SEM, n=6) at 1-2 days to 48.3±5.1% at 4 days, and 61.2±6.2% by 6-7 days. Optimal doses of ADC ranged from 500ng-1ug/ml. In summary, these preclinical data in MM support the potential utility of an anti-BCMA ADC across the whole MM population, perhaps with particular efficacy in patients with adverse genetics, for whom an unmet need remains. Disclosures: Yong: GSK: Research Funding. Germaschewski:GSK: Employment. Mayes:GlaxoSmithKline: Employment. Sully:GlaxoSmithKline: Employment. Seestaller-Wehr:GlaxoSmithKline: Employment. Fieles:GlaxoSmithKline: Employment. Tunstead:GlaxoSmithKline: Employment. McCahon:GlaxoSmithKline: Employment. Craigen:GlaxoSmithKline: Employment.

p53 overexpression and loss of PTEN expression have been implicated in the pathogenesis of endometrial cancer. Our aim was to correlate expression levels of these proteins with clinicopathological parameters to characterise their utility as biomarkers. Immunohistochemistry was done on 49 cases of formalin fixed paraffin embedded endometrial cancer tissue for p53 and 47 for PTEN expression. For p53 staining the Hue Saturation and Intensity mathematical model was used to evaluate different degrees of positivity of the immunohistochemical stain. The quick score was used for p53 and immunoreactive score for PTEN was done to score immunoreactivity. For PTEN, average percentage of positive cells and intensity was evaluated and the immunoreactive score was calculated. Both these scoring methods incorporated percentage of positive cells and staining intensity. Univariate Cox regression analysis for cause specific survival showed a hazard ratio of 9.2 for p53 overexpression (P Overexpression of P53 has a negative effect on disease specific survival and was associated with poor prognostic features. We did not demonstrate a significant association with clinicopathological features assessed and PTEN expression. However of the 8 patients who relapsed all were PTEN negative and 7 were p53 positive. Dual assessment of p53 and PTEN warrants further investigation as a prognostic indicator. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C32. Citation Format: Bihani Kularatne, Arrigo Capitanio, Rupali Arora, Philippa Jones, Andre Lopes, Jennifer Paterson, Rebecca Kristeleit. PTEN and p53 expression in endometrial cancer correlated with clinicopathological phenotype. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C32.

A 180,388-bp contig encompassing the human retinoblastoma gene was sequenced in its entirety. Partial analysis of the sequence revealed (1) a high (A + T)/(G + C) ratio and a high density of Line-1 (L1) repeat sequences, suggesting that the locus maps to G-bands 13q14.12 or 13q14.2; (2) Alu repeats that are asymmetrically oriented over a region extending 87 kb; (3) an overabundance of non-Alu-associated poly(A) tracts 10 bp or larger oriented in the antisense rather than the sense direction (36 vs 6); (4) an Alu sequence nested within an L1 repeat, indicating that the expansion of L1 repeats predates at least some of the Alu expansions; (5) at least three newly discovered microsatellite polymorphisms, one of which was subsequently found to be identical to a polymorphism in a microsatellite-based linkage map of the human genome published by another group; and (6) the basis of previously discovered intragenic RFLPs. This sequence should enhance studies of this locus and of the organization of the human genome.

Abstract 2942 Poster Board II-918 Introduction: LMO2 is a transcription factor with a central role in haematopoietic development and angiogenesis. High levels of LMO2 transcript were reported in CD34+ stem cells and strong protein expression was observed in endothelia, germinal centre B cells (GCB) and some B cell lymphomas. Activation of LMO2 has been demonstrated in T-ALL as a consequence of translocations or deletions and its expression in diffuse large B-cell lymphomas is associated with favourable outcome. Furthermore, correlation between LMO2 expression and tumour progression has been reported in prostatic carcinoma. Aims: The expression pattern of a newly developed rabbit monoclonal antibody raised against a fixation-resistant epitope of the LMO2 protein was studied in human normal and pathologic samples. Material and Methods: Normal haematopoietic and non-haematopoietic tissue sections, tissue micro-arrays including 1452 neoplastic samples, 11 lymphoma-derived cell lines and CD34+/CD38− stem cells, purified from human umbilical cord blood, were investigated by single and double immunostaining. Results and discussion: Strong LMO2 expression was found in CD34+/CD38− stem cells and in contrast to previous studies, the anti-LMO2 rabbit monoclonal distinctively labelled normal mantle, monocytoid and splenic marginal zone B cells. A few LMO2+/CD34+ cells were detected in the thymic cortex, most likely representing T cell precursors. Tables 1 and 2 summarise the results obtained in tumours and lymphoma-derived cell lines. Among B cell neoplasms, LMO2 was highly expressed in B-lymphoblastic lymphoma/leukaemia (87%) and heterogeneously in MCL (14%), FL (57%) and BL (37%). In DLBCL, LMO2 positivity was closely related to those cases with a “germinal centre” phenotype. LMO2 nuclear positivity was observed in all cases of LPHL; interestingly Reed-Sternberg cells in CHL showed LMO2 cytoplasmic staining in 10% of cases. The constant expression in T-ALL highlights the pathogenetic role and diagnostic significance of LMO2 in this setting as opposed to PTCLs (usually negative). Detection of LMO2 was observed in the majority of AML and CML cases investigated. Different types of carcinoma expressed LMO2 that was found to be mainly cytoplasmic. Conclusion: The newly developed anti-LMO2 rabbit monoclonal antibody represents a powerful reagent for detection of LMO2 protein in routine samples as compared to the previously published monoclonal anti-LMO2. Its frequent expression among haematological malignancies (e.g. T-ALL, B-ALL and AML) indicates LMO2 as putative therapeutic target as evidenced by RNA-silencing studies in experimental models. Disclosures: No relevant conflicts of interest to declare.

Hodgkin/Reed-Sternberg cells (HRS cells) are thought to be derived from post-germinal centre B-cells and yet have down-regulated the B-cell phenotype. The B-cell transcription factor Pax5 is important in the maintenance of B-cell identity and we demonstrate that it is down-regulated in HRS cells lines and in HRS cells of the majority of primary classical Hodgkin Lymphoma (cHL) cases. Specifically, 3/30 cases were negative for Pax5, 16/30 were weakly positive, 10/30 cases were moderately positive and 1/30 showed Pax5 staining of equivalent intensity to infiltrating, polyclonal B-cells. In order to functionally test the relevance of a reduced Pax5 expression level, the cHL cell lines L428 and L1236 were stably transfected with Pax5 using a lentiviral transfection system. Transfection of L1236 resulted in up-regulation of CD79a protein expression. However, CD79a was not upregulated in L428 and expression of the Pax5 target genes Cd19 and Blnk was unaffected by Pax5 transfection in both cell lines. Chromatin immunoprecipitation demonstrated that Pax5 failed to bind the high affinity binding site within the Cd19 promoter in the cHL lines despite high levels of Pax5 expression, appropriately localised to the nucleus. Pax5 could, however, bind synthetic oligonucleotide corresponding to this site (as shown by electrophoretic mobility shift assays) raising the possibility that epigenetic modification in vivo may be responsible for the failure to bind DNA. Bisulphite genome sequencing confirmed that in cHL cell lines, the region surrounding the Pax5 binding site in the Cd19 promoter was extensively methylated. Moreover, histone modification analysis also demonstrated an absence of markers of accessible, active chromatin (di- and trimethylated H3K4) and an enrichment of a marker indicating closed, repressive chromatin (trimethylated H3K27). Within the Cd79a promoter, previous studies have implicated the methylation status of a single cytosine residue within the binding site for a Pax5-Ets1 complex to be an important determinant of activation of the Cd79a gene. Interestingly, this residue was shown to be largely methylated in L428 cells but largely unmethyated in L1236 cells, providing a likely mechanism for the differential activation of this gene by transfected Pax5 protein. To investigate whether the observed epigenetic changes were responsible for preventing Pax5 binding and activity at the Cd19 and Cd79a promoters, Pax5 transfected cHL cell lines were cultured in the presence of the demethylating agent 5-aza-2-deoxycytidine. Up-regulation of Cd19 and Cd79a expression was significantly greater in Pax5 transfected cells than in control transfected cells. To conclude: our data suggests that dysregulation of Pax5 activity (at the levels of protein expression and epigenetic modification of the Pax5 binding sites) is important in mediating the extinction of the B-cell programme in HRS cells.

Despite the immunologic functions of T-cell receptor signaling molecules being extensively investigated, their potential as immunohistochemical markers has been poorly explored. With this background, we evaluated the expression of 5 intracellular proteins-GADS, DOK2, SKAP55, ITK, and PKCα-involved in T-cell receptor signaling in normal and neoplastic hematologic tissue samples, using antibodies raised against fixation-resistant epitopes of the 5 molecules. All 5 antibodies were associated with normal T-cell differentiation. GADS, DOK2, SKAP55, and ITK turned out to be T-cell lineage-specific markers in the setting of lymphoid and myeloid precursor neoplasms but showed differential expression in peripheral T-cell lymphoma (PTCL) subtypes, being detected in PTCL/not otherwise specified (NOS) and angioimmunoblastic T-cell lymphoma but negative in anaplastic large cell lymphoma (ALCL). Peripheral B-cell lymphomas were consistently negative for ITK, with occasional cases showing expression of DOK2 and SKAP55, and a proportion (47%) of hairy cell leukemias were GADS. Notably, PKCα highlighted a defective antigen in both PTCL/NOS (6%) and angioimmunoblastic T-cell lymphoma (10%), mostly negative in ALCL, and was aberrantly expressed in classical Hodgkin lymphoma (65%), Burkitt lymphoma (48%), and plasma cell myeloma (48%). In conclusion, all five molecules evaluated play a role in T-cell differentiation in normal and neoplastic tissues. They can be applied confidently to routine sections contributing primarily to assignment of T-lineage differentiation in the setting of hematopoietic precursor neoplasms (GADS/DOK2/SKAP55/ITK) and for the differential diagnosis between ALCL and PTCL/NOS (GADS/DOK2/SKAP55/ITK) or classical Hodgkin lymphoma (PKCα). Finally, association with specific tumor subtypes may have therapeutic potential.