Nestin expression in osteocytes following myeloablation and during bone marrow metastasis

Nestin is an intermediate filament protein, which was originally detected in neuroepithelial stem cells. Besides its use as a phenotypic marker of mesenchymal stem cells in the hematopoeitic stem cell niche, the functional interpretation of nestin⁺ cells remains elusive. We investigated the cellular expression of nestin in bone marrow trephine biopsies of MPN patients, following myeloablation at a stage of hypocellularity during early regeneration. Here, nestin is highly expressed in mature osteocytes, arteriolar endothelial and perivascular cells and small capillaries within the bone marrow space, but not in sinusoid lining cells. This is in stark contrast to nestin expression pattern in myeloproliferative neoplasms that show hypercellularity due to oncogenic driver mutations. Here, nestin is expressed exclusively in endothelial cells of arterioles, but not in osteocytes or small capillaries. Thus, the pattern of nestin expression following myeloablation inversely correlates with cellularity in the bone marrow. This nestin expression pattern is mimicking early postnatal transcriptional programming during bone marrow development. We show that nestin expression in osteocytes occurs across different species following transplant and also in bone marrow metastasis.

Blastic plasmacytoid dendritic-cell neoplasia: a challenging case report

Blastic plasmacytoid dendritic-cell neoplasm (BPDCN) is an extremely rare disease that originates from dendritic cells and is associated with a poor overall survival (OS). Diagnostic and therapeutic standards are less well-established in comparison to other leukemic conditions and standards of care are lacking. Morphologic and molecular similarities to acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) are hard to distinguish. We here report a BPDCN patient with a long, challenging diagnostic period. While bone marrow biopsies initially failed to prove the correct diagnosis, a cutaneous biopsy finally identified a CD45⁺/CD56⁺/CD4⁺/CD123⁺/CD33⁺/MPO⁻ population suggestive of BPDCN which was confirmed by flow cytometry. Molecular analysis revealed an ASXL-1, TET2 and SRSF2-mutation, cytogenetic analysis showed a normal karyotype. Treatment with the recently approved CD123-cytotoxin Tagraxofusp showed initially a very good response. This case reflects diagnostic and therapeutic difficulties in BPDCN as very rare, easily misdiagnosed neoplasia and the need for precise diagnostic care.

Macrophage frequency in the bone marrow correlates with morphologic subtype of myeloproliferative neoplasm

Bone marrow (BM) fibrosis in myeloproliferative neoplasms (MPNs) is associated with a poor prognosis. The development of myelofibrosis and differentiation of mesenchymal stromal cells to profibrotic myofibroblasts depends on macrophages. Here, we compared macrophage frequencies in BM biopsies of MPN patients and controls (patients with non-neoplastic processes), including primary myelofibrosis (PMF, n = 18), essential thrombocythemia (ET, n = 14), polycythemia vera (PV, n = 12), and Philadelphia chromosome-positive chronic myeloid leukemia (CML, n = 9). In PMF, CD68-positive macrophages were greatly increased compared to CML (p = 0.017) and control BM (p < 0.001). Similar findings were observed by CD163 staining (PMF vs. CML: p = 0.017; PMF vs. control: p < 0.001). Moreover, CD68-positive macrophages were increased in PV compared with ET (p = 0.009) and reactive cases (p < 0.001). PMF had higher frequencies of macrophages than PV (CD68: p < 0.001; CD163: p < 0.001) and ET (CD68: p < 0.001; CD163: p < 0.001). CD163 and CD68 were often co-expressed in macrophages with stellate morphology in Philadelphia chromosome-negative MPN, resulting in a sponge-like reticular network that may be a key regulator of unbalanced hematopoiesis in the BM space and may explain differences in cellularity and clinical course.

Increased IgG4-positive plasma cells in nodular-sclerosing Hodgkin lymphoma: a diagnostic pitfall

AIMS

Despite increasing interest in the recently established immunoglobulin 4-related disease (IgG4-RD), its pathogenesis and aetiology remain largely unclear. Characteristic histopathological features are one of the key elements of diagnosis, including 'storiform' fibrosis, obliterative phlebitis, increased lymphoplasmacytic infiltration and increased levels of IgG4 in serum and tissue. Histopathological features of IgG4-RD are striking but not specific, and can pose a pitfall for surgical pathologists. This paper aims to determine the actual amount of IgG4+ plasma cells in nodular-sclerosing Hodgkin lymphoma (NSHL) and its potential to be misdiagnosed in routine clinical practice.

METHODS AND RESULTS

IgG4+ plasma cells per high-power field (HPF) and the ratio of IgG4+ versus IgG+ plasma cells (IgG4/IgG ratio) in lymph node biopsies of 24 patients with nodular-sclerosing Hodgkin lymphoma (NSHL) were determined using immunohistochemistry and consensus scoring criteria as used for IgG4-RD. Ten lymph node biopsies with reactive follicular hyperplasia were assessed for comparison. Higher numbers of IgG4+ plasma cells (P < 0.001) were observed in NSHL versus follicular hyperplasia (mean 34 versus 8 per HPF) with a mean IgG4/IgG ratio of 0.38 versus 0.18. Five cases (21%) fulfilled the consensus criteria of IgG4-RD, with >50 IgG4+ plasma cells per HPF and an IgG4/IgG ratio of >0.4. The mean count of IgG4+ plasma cells per HPF in NSHL varied greatly (3-88) with increased numbers of IgG4+ plasma cells seen near areas of fibrosclerosis.

CONCLUSIONS

Significantly higher levels of IgG4+ plasma cells are common in NSHL, emphasising the need to exclude Reed-Sternberg cells by morphology and immunohistochemistry in biopsies where IgG4-RD is suspected.

Prognostic profiling of the immune cell microenvironment in Ewing´s Sarcoma Family of Tumors

Ewing´s Sarcoma Family of Tumors (ESFT) are clinically aggressive bone and soft tissue tumors in children and young adults. Analysis of the immune tumor microenvironment (TME) provides insight into tumor evolution and novel treatment options. So far, the scarcity of immune cells in ESFT has hindered a comprehensive analysis of rare subtypes. We determined the relative fraction of 22 immune cell types using 197 microarray gene expression datasets of primary ESFT tumor samples by using CIBERSORT, a deconvolution algorithm enumerating infiltrating leucocytes in bulk tumor tissue. The most abundant cells were macrophages (mean 43% of total tumor-infiltrating leukocytes, TILs), predominantly immunosuppressive M2 type macrophages, followed by T cells (mean 23% of TILs). Increased neutrophils, albeit at low number, were associated with a poor overall survival (OS) (p = .038) and increased M2 macrophages predicted a shorter event-free survival (EFS) (p = .033). High frequency of T cells and activated NK cells correlated with prolonged OS (p = .044 and p = .007, respectively). A small patient population (9/32) with combined low infiltrating M2 macrophages, low neutrophils, and high total T cells was identified with favorable outcome. This finding was confirmed in a validation cohort of patients with follow up (11/38). When comparing the immune TME with expression of known stemness genes, hypoxia-inducible factor 1 α (HIF1α) correlated with high abundance of macrophages and neutrophils and decreased T cell levels. The immune TME in ESFTs shows a distinct composition including rare immune cell subsets that in part may be due to expression of HIF1α.

Anemia in the aged is not ageing related: position paper on anemia in the aged by the "working group anemia" of the German Geriatric Society (DGG)

Anemia in the aged is a frequent but still under-estimated problem in geriatric patients. However, in recent years increasing research on anemia in the aged has improved awareness and interest in this clinically relevant problem. Guidelines for diagnostic and therapeutic steps are now required to improve the treatment of anemic aged patients. For encouraging the development of diagnostic and therapeutic recommendations, the "working group anemia" of the German Geriatric Society (DGG) has issued a position paper on anemia in the aged, based on the current literature. The statements are (1) that anemia has to be considered a highly prevalent but not a physiologic finding in aged persons; (2) that reference values for hemoglobin concentration are independent of age, indicating that WHO reference values for anemia definition are valid for aged persons; (3) that anemia in the aged is associated with functional and cognitive impairment based on comprehensive geriatric assessment (CGA), requiring diagnosis and treatment.

Low BUB1 expression is an adverse prognostic marker in gastric adenocarcinoma

Gastric adenocarcinomas are associated with a poor prognosis due to the fact that the tumor has often metastasized by the time of diagnosis and prognostic markers are urgently needed to tailor treatment.

We examined the expression of the mitotic spindle checkpoint protein BUB1 (budding uninhibited by benzimidazoles 1) and Ki-67 protein expression by immunohistochemistry in 218 patients with primary gastric adenocarcinomas.

Tumors with low frequency of BUB1 expression were associated with larger tumor size (pT) (p < 0.001), higher incidence of lymph node metastases (pN) (p = 0.027), distant metastases (pM) (p = 0.006) and higher UICC stage (p < 0.001). Furthermore, BUB1 expression was inversely correlated with residual tumor stage (p = 0.038). Abundant BUB1 protein expression correlated with frequent Ki-67 protein expression (p < 0.001) and low BUB1 expression was associated with shorter survival (p < 0.001). Univariate and multivariate analyses confirmed BUB1 to be an independent prognostic marker in gastric cancer (p = 0.021).

MYC regulates the antitumor immune response through CD47 and PD-L1

The MYC oncogene codes for a transcription factor that is overexpressed in many human cancers. Here we show that MYC regulates the expression of two immune checkpoint proteins on the tumor cell surface: the innate immune regulator CD47 (cluster of differentiation 47) and the adaptive immune checkpoint PD-L1 (programmed death-ligand 1). Suppression of MYC in mouse tumors and human tumor cells caused a reduction in the levels of CD47 and PD-L1 messenger RNA and protein. MYC was found to bind directly to the promoters of the Cd47 and Pd-l1 genes. MYC inactivation in mouse tumors down-regulated CD47 and PD-L1 expression and enhanced the antitumor immune response. In contrast, when MYC was inactivated in tumors with enforced expression of CD47 or PD-L1, the immune response was suppressed, and tumors continued to grow. Thus, MYC appears to initiate and maintain tumorigenesis, in part, through the modulation of immune regulatory molecules.

Combinations of immunostimulatory antibodies with synergistic effects against spontaneous cancer

Immunostimulatory monoclonal antibodies can be given in combinations, hence modulating the activity of 2 or more receptors of the immune system. Some of these combinations have been shown to synergize at the elicitation of therapeutically relevant immune responses in transgenic mice developing spontaneous, oncogene-driven tumors, including multifocal hepatocellular carcinomas expressing ovalbumin as a surrogate tumor-associated antigen.

Combined immunostimulatory monoclonal antibodies extend survival in an aggressive transgenic hepatocellular carcinoma mouse model

PURPOSE

Immunostimulatory monoclonal antibodies (ISmAb) that unleash antitumor immune responses are showing efficacy in cancer clinical trials. Anti-B7-H1 (PD-L1) monoclonal antibodies (mAb) block a critical inhibitory pathway in T cells, whereas anti-CD137 and OX40 mAbs provide T-cell costimulation. A combination of these ISmAbs (anti-CD137 + anti-OX40 + anti-B7-H1) was tested using a transgenic mouse model of multifocal and rapidly progressing hepatocellular carcinoma, in which c-myc drives transformation and cytosolic ovalbumin (OVA) is expressed in tumor cells as a model antigen.

EXPERIMENTAL DESIGN

Flow-cytometry and immunohistochemistry were used to quantify tumor-infiltrating lymphocytes (TIL) elicited by treatment and assess their activation status and cytolytic potential. Tolerance induction and its prevention/reversal by treatment with the combination of ISmAbs were revealed by in vivo killing assays.

RESULTS

The triple combination of ISmAbs extended survival of mice bearing hepatocellular carcinomas in a CD8-dependent fashion and synergized with adoptive T-cell therapy using activated OVA-specific TCR-transgenic OT-1 and OT-2 lymphocytes. Mice undergoing therapy showed clear increases in tumor infiltration by activated and blastic CD8(+) and CD4(+) T lymphocytes containing perforin/granzyme B and expressing the ISmAb-targeted receptors on their surface. The triple combination of ISmAbs did not result in enhanced OVA-specific cytotoxic T lymphocyte (CTL) activity but other antigens expressed by cell lines derived from such hepatocellular carcinomas were recognized by endogenous TILs. Adoptively transferred OVA-specific OT-1 lymphocytes into tumor-bearing mice were rendered tolerant, unless given the triple mAb therapy.

CONCLUSION

Extension of survival and dense T-cell infiltrates emphasize the translational potential of combinational immunotherapy strategies for hepatocellular carcinoma. Clin Cancer Res; 19(22); 6151-62. ©2013 AACR.

Intravoxel incoherent motion model-based liver lesion characterisation from three b-value diffusion-weighted MRI

OBJECTIVE

To evaluate intravoxel incoherent motion (IVIM) model-based liver lesion characterisation from three b-value diffusion-weighted imaging (DWI).

METHODS

The 1.5-T DWI data from a respiratory gated spin-echo echo-planar magnetic resonance imaging sequence (b = 0, 50, 800 s/mm(2)) were retrospectively analysed in 38 patients with different liver lesions. Conventional apparent diffusion coefficient ADC = ADC(0,800) as well as IVIM-based parameters D' = ADC(50,800), ADC_low = ADC(0,50), and f' were calculated voxel-wise. Sixty-one regions of interest in hepatocellular carcinomas (HCCs, n = 24), haemangiomas (HEMs, n = 11), focal nodular hyperplasias (FNHs, n = 11), and healthy liver tissue (REFs, n = 15) were analysed. Group differences were investigated using Student's t-test and receiver-operating characteristic (ROC) analysis.

RESULTS

Mean values ± standard deviations of ADC, D', ADC_low (in 10(-5) mm(2)/s), and f' (in %) for REFs/FNHs/HEMs/HCCs were 130 ± 11/143 ± 27/168 ± 16/113 ± 25, 104 ± 12/123 ± 25/162 ± 18/102 ± 23, 518 ± 66/437 ± 97/268 ± 69/283 ± 120, and 18 ± 3/14 ± 4/6 ± 3/9 ± 5, respectively. Differences between lesions and REFs were more significant for IVIM-based parameters than for conventional ADC. ROC analysis showed the best discriminability between HCCs and FNHs for ADC_low and f' and between HEMs and FNHs or HCCs for D'.

CONCLUSION

Three instead of two b-value DWI enables a numerically stable and voxel-wise IVIM-based analysis for improved liver lesion characterisation with tolerable acquisition time.

KEY POINTS

• Quantitative analysis of diffusion-weighted MRI helps liver lesion characterisation. • Analysis of intravoxel incoherent motion is superior to apparent diffusion coefficient determination. • Only three b-values enable separation of diffusion and microcirculation effects. • The method presented is numerically stable, with voxel-wise results and short acquisition times.

Alterations of global histone H4K20 methylation during prostate carcinogenesis

Background

Global histone modifications have been implicated in the progression of various tumour entities. Our study was designed to assess global methylation levels of histone 4 lysine 20 (H4K20me1-3) at different stages of prostate cancer (PCA) carcinogenesis.

Methods

Global H4K20 methylation levels were evaluated using a tissue microarray in patients with clinically localized PCA (n = 113), non-malignant prostate disease (n = 27), metastatic hormone-naive PCA (mPCA, n = 30) and castration-resistant PCA (CRPC, n = 34). Immunohistochemistry was performed to assess global levels of H4K20 methylation levels.

Results

Similar proportions of the normal, PCA, and mPCA prostate tissues showed strong H4K20me3 staining. CRPC tissue analysis showed the weakest immunostaining levels of H4K20me1 and H4K20me2, compared to other prostate tissues. H4K20me2 methylation levels indicated significant differences in examined tissues except for normal prostate versus PCA tissue. H4K20me1 differentiates CRPC from other prostate tissues. H4K20me1 was significantly correlated with lymph node metastases, and H4K20me2 showed a significant correlation with the Gleason score. However, H4K20 methylation levels failed to predict PSA recurrence after radical prostatectomy.

Conclusions

H4K20 methylation levels constitute valuable markers for the dynamic process of prostate cancer carcinogenesis.

Deep sequencing of MYC DNA-binding sites in Burkitt lymphoma

Background

MYC is a key transcription factor involved in central cellular processes such as regulation of the cell cycle, histone acetylation and ribosomal biogenesis. It is overexpressed in the majority of human tumors including aggressive B-cell lymphoma. Especially Burkitt lymphoma (BL) is a highlight example for MYC overexpression due to a chromosomal translocation involving the c-MYC gene. However, no genome-wide analysis of MYC-binding sites by chromatin immunoprecipitation (ChIP) followed by next generation sequencing (ChIP-Seq) has been conducted in BL so far.

Methodology/Principal Findings

ChIP-Seq was performed on 5 BL cell lines with a MYC-specific antibody giving rise to 7,054 MYC-binding sites after bioinformatics analysis of a total of approx. 19 million sequence reads. In line with previous findings, binding sites accumulate in gene sets known to be involved in the cell cycle, ribosomal biogenesis, histone acetyltransferase and methyltransferase complexes demonstrating a regulatory role of MYC in these processes. Unexpectedly, MYC-binding sites also accumulate in many B-cell relevant genes. To assess the functional consequences of MYC binding, the ChIP-Seq data were supplemented with siRNA- mediated knock-downs of MYC in BL cell lines followed by gene expression profiling. Interestingly, amongst others, genes involved in the B-cell function were up-regulated in response to MYC silencing.

Conclusion/Significance

The 7,054 MYC-binding sites identified by our ChIP-Seq approach greatly extend the knowledge regarding MYC binding in BL and shed further light on the enormous complexity of the MYC regulatory network. Especially our observations that (i) many B-cell relevant genes are targeted by MYC and (ii) that MYC down-regulation leads to an up-regulation of B-cell genes highlight an interesting aspect of BL biology.

Global levels of histone modifications predict prostate cancer recurrence

PURPOSE

Epigenetic alterations such as DNA methylation and histone modifications play important roles in carcinogenesis. It was reported that global histone modification patterns are predictors of cancer recurrence in various tumor entities. Our study was performed to evaluate histone lysine (H(x)K(y)) and histone acetyl (H(x)Ac) modifications in prostate tissue.

MATERIALS AND METHODS

A tissue microarray with 113 prostate cancer (PCA), 23 non-malignant prostate tissues was stained with antibodies against H3K4 mono-(H3K4me1), di-(H3K4me2), tri-(H3K4me3) methylation, H3K9me1, H3K9me2, H3K9me3, H3 and H4 pan-acetylation (H3Ac, H4Ac). We also analyzed H3K4 methylation in patients with advanced PCA (hormone-refractory PCA-HRPC, n = 34; hormone-dependent PCA, n = 30). Sections were scored according the staining intensity and the proportion of epithelial cells showing nuclear staining.

RESULTS

H3K4me1, H3K9me2, H3K9me3, H3Ac, and H4Ac were significantly reduced in PCA compared to non-malignant prostate tissue. H3Ac and H3K9me2 levels allowed discrimination of PCA and non-malignant prostate tissue highly specifically (>91%) and sensitively (>78%) as determined via ROC analyses (AUC >0.91). Histone lysine methylation and histone acetylation marks were correlated with clinical-pathological parameters (i.e., digital rectal examination, preoperative PSA, pT-stage, lymph node metastasis, Gleason score). In addition, H3K4me1 was a significant predictor of PSA recurrence following radical prostatectomy. H3K4me1, H3K4me2, and H3K4me3 levels were significantly increased in HRPC.

CONCLUSIONS

Global histone modification levels may help to identify patients with adverse prognosis, and represent a target for the future therapy of PCA.

H3K4 dimethylation in hepatocellular carcinoma is rare compared with other hepatobiliary and gastrointestinal carcinomas and correlates with expression of the methylase Ash2 and the demethylase LSD1

Methylation of core histones regulates chromatin structure and gene expression. Recent studies have demonstrated that these methylation patterns have prognostic value for some tumors. Therefore, we investigated dimethylation of histone H3 at lysine 4 (H3K4diMe) and H3K4 methylating (Ash2 complex) and demethylating enzymes (LSD1) in carcinomas of the hepatic and gastrointestinal tract. High levels of H3K4diMe were rarely observed in 15.7% of hepatocellular carcinoma (8/51) unlike other carcinomas including, in ascending order, cholangiocellular carcinoma/adenocarcinoma of the extrahepatic biliary tract, gastric carcinoma, pancreatic ductal adenocarcinoma, and neuroendocrine carcinoma (P < .001). Ash2 was expressed in 84.4% of hepatocellular carcinomas (38/45) and correlated directly with H3K4diMe modification (correlation coefficient r = 0.53) and LSD1 expression (r = 0.35). In contrast to other carcinomas, 65.9% (29/44) of hepatocellular carcinomas analyzed showed no LSD1 expression (P < .001). Interestingly, hepatocellular carcinomas without LSD1 expression appeared to be frequently Ash2 and H3K4diMe weak or negative (P = .004). In summary, high H3K4diMe expression is rare in hepatocellular carcinoma compared with other carcinomas (negative predictive value 92.3%), which may aid in the differential diagnosis. Lack of H3K4diMe is possibly due to complex epigenetic regulation involving Ash2 and LSD1.

Lymph node dissection in primary intrahepatic malignant mesothelioma: case report and implications for diagnosis and therapy

INTRODUCTION

In this rare case of intrahepatic malignant mesothelioma with subsequent lymph node metastases, hepatic segmentectomy in combination with repeated lymphadenectomy resulted in prolonged survival, currently 37 months after initial diagnosis.

DISCUSSION

Immunohistochemically, vascular endothelial growth factor receptor-1 expressing tumor cells were surrounded by a dense D 2-40-positive lymphangiovascular network, suggesting tumor induced lymphangiogenesis correlating to 2-deoxy-2[(18)F]fluoro-d-glucose-positron emission tomography/computed tomography-positive recurrent intraabdominal and intrathoracic lymphatic tumor spread. Therefore, extended lymphadenectomy during primary tumor resection and combined adjuvant chemotherapy with promising anticancer agents possessing antilymphangiogenic and antimetabolite properties should be considered to prolong survival in cases of extrathoracic malignant mesothelioma. Additionally, as shown in our case, individual operative concepts and (sometimes) multiple operations can be beneficial for highly selected patients. Importantly, a case-by-case optimized antitumor regimen requires interdisciplinary expertise and consensus of all involved faculties.

Autochthonous liver tumors induce systemic T cell tolerance associated with T cell receptor down-modulation

The reason the adaptive immune system fails in advanced liver tumors is largely unclear. To address this question, we have developed a novel murine model that combines c-myc-induced autochthonous tumorigenesis with expression of a cognate antigen, ovalbumin (OVA). When c-myc/OVA transgenic mice were crossed with liver-specific inducer mice, multifocal hepatocellular carcinomas co-expressing OVA developed in a tetracycline-dependent manner with a short latency and 100% penetrance. Transferred OVA-specific T cells, although infiltrating the tumor at high numbers, were hyporesponsive, as evidenced by a lack of in vivo cytotoxicity and interferon gamma production. This allowed the tumor to progress even in the presence of large numbers of antigen-specific T cells and even after vaccination (OVA+CpG-DNA). Interestingly, T cell receptor down-modulation was observed, which may explain antigen-specific hyporesponsiveness. This model is helpful in understanding liver cancer-specific mechanisms of T cell tolerance and dissection of antigen-specific and nonspecific mechanisms of immunotherapies in the preclinical phase.

Stem cell marker expression in small cell lung carcinoma and developing lung tissue

Histopathologic and clinical findings suggest that small cell lung cancer is derived from a multipotent proximal airway epithelial cell. In order to investigate the histogenetic origin of small cell lung cancer, we compared stem cell marker expression in human fetal lung tissue, human adult bronchial tissue, and a cohort of 64 small cell lung cancers. Supporting derivation of a multipotent precursor cell, 87.5% (56/64) of small cell lung cancers showed a dot-like expression of podocalyxin-like protein 1 (PODXL-1), a marker of embryonic and hematopoetic stem cells. Of small cell lung cancers, 98.4% (63/64) ubiquitously expressed Bmi-1, a key player in self-renewal of stem cells. Oct4 and AP2gamma were not expressed. Although podocalyxin-like protein 1 did not correlate with p53 or Wilms tumor suppressor 1, known regulators of podocalyxin-like protein 1, we could demonstrate demethylated CpG islands in the podocalyxin-like protein 1 promoter in small cell lung cancer, indicating epigenetic regulation. During fetal lung development and within adult bronchial mucosa, Bmi-1 was expressed ubiquitously. In contrast, podocalyxin-like protein 1 was detected in few stromal cells during the pseudoglandular phase (n = 7) and, importantly, in clustered epithelial cells within proximal bronchi and the trachea during the canalicular phase (n = 10). Interestingly, podocalyxin-like protein 1 was not expressed in normal or metaplastic adult bronchial epithelium (n = 36) but was expressed in sparse epithelial cells in half of the cases of normal tumor adjacent bronchial mucosa (20/40). Taken together, we show that small cell lung cancers and clustered epithelial cells in developing proximal bronchi share the expression of stem cell markers, suggesting a possible histogenetic link.

Argyrin a reveals a critical role for the tumor suppressor protein p27(kip1) in mediating antitumor activities in response to proteasome inhibition

A reduction in the cellular levels of the cyclin kinase inhibitor p27(kip1) is frequently found in many human cancers and correlates directly with patient prognosis. In this work, we identify argyrin A, a cyclical peptide derived from the myxobacterium Archangium gephyra, as a potent antitumoral drug. All antitumoral activities of argyrin A depend on the prevention of p27(kip1) destruction, as loss of p27(kip1) expression confers resistance to this compound. We find that argyrin A exerts its effects through a potent inhibition of the proteasome. By comparing the cellular responses exerted by argyrin A with siRNA-mediated knockdown of proteasomal subunits, we find that the biological effects of proteasome inhibition per se depend on the expression of p27(kip1).

Inverse expression of Jun activation domain binding protein 1 and cell cycle inhibitor p27Kip1: influence on proliferation in hepatocellular carcinoma

Recently, the functional role of Jun activation domain binding protein 1 (Jab1) as a putative novel oncogene in hepatocellular carcinoma (HCC) has been postulated. We show that expression of p27(Kip1), a negative cell cycle regulator, correlates inversely with Jab1 expression in HCC (P = .014). We observed nuclear Jab1 expression in 57% (55/97) and p27(Kip1) expression in 32% (31/97) of HCCs. Neither Jab1 nor p27(Kip1) nor inverse Jab1 and p27(Kip1) expression correlated with clinicopathological parameters. However, HCCs lacking p27(Kip1) with increased proliferative activity were frequently found to express Jab1 (P = .048). Normal liver tissue, cirrhosis, and tumor-like lesions (focal nodular hyperplasia, dysplastic nodules in cirrhotic liver) showed no significant Jab1 expression. In transfection studies in the hepatoma cell line Huh 7, Jab1 overexpression resulted in reduced p27(Kip1) protein levels. We conclude that Jab1 expression may lead to down-regulation of the negative cell cycle regulator p27(Kip1), pointing to a possible mechanism that promotes hepatocarcinogenesis.

Intrahepatic Clear Cell Cholangiocarcinoma

Clear cell cholangiocarcinoma is a very unusual variant of peripheral bile duct carcinoma. We present 3 cases on which we performed a broad spectrum of immunohistochemical analysis. The tumors showed a glandular and trabecular growth pattern with abundant desmoplastic stroma and clear cell change of about 80% of the tumor cells. Positive expression of CK7 indicated a cholangiocellular origin. A primary hepatocellular carcinoma and metastatic clear cell tumors of the kidney, gastrointestinal tract, and the thyroid gland were excluded by absence of CK20, CD10, HepPar1, and TTF1. No mucin could be detected within the cytoplasm of the clear cells. Electronmicroscopy revealed only a few glycogen granula, but numerous cytoplasmic lipoid vacuoles as a possible explanation for the clear cell phenotype. All 3 tumors exhibited positive expression of CD56 (NCAM) in a significant amount of the clear cells. Beside the clear cell component, one tumor also showed an adenocarcinomalike and a well-differentiated tubular component. CD56 expression was detected in all 3 tumor areas. This report of 3 cases demonstrates that clear cell cholangiocarcinomas are not only of unusual histomorphology. They also show CD56 expression which is a very uncommon finding for intrahepatic cholangiocarcinomas. As CD56 expression is also found in reactive bile ducts and bile duct adenomas, one may speculate that these rare neoplasms may originate from reactive bile ducts or cholangiomatous lesions.

Hodgkin’s lymphoma in a patient with Jo-1 syndrome

Jo-1 syndrome is an autoimmune disease with autoantibodies against the histidyl tRNA synthetase. Characteristic clinical findings include inflammatory myopathy and interstitial lung disease. We present the first case of a patient with Jo-1 syndrome (positive Jo-1 autoantibodies, myositis, interstitial alveolitis) who developed Hodgkin's lymphoma of nodular-sclerosing type. Thus, patients with Jo-1 syndrome and immunosuppressive therapy similar to other patients with autoimmune disease are at risk to develop lymphomas and should therefore be monitored carefully.

Podocalyxin-like protein 1 expression is useful to differentiate pancreatic ductal adenocarcinomas from adenocarcinomas of the biliary and gastrointestinal tracts

Metastases of adenocarcinomas from the pancreas, liver, and gastrointestinal tract are difficult to distinguish from each other because of their similar morphological and immunohistochemical features. So far, no specific marker for pancreatic ductal adenocarcinomas has been described. Podocalyxin-like protein 1 (PODXL-1) is expressed on vascular endothelium, hematopoietic precursor cells, and renal podocytes. We found that 44% (71/160) of pancreatic ductal adenocarcinomas expressed PODXL-1 in a membranous pattern. There was no expression in intrahepatic cholangiocarcinomas (0/18, P < .001), rarely in adenocarcinomas of the extrahepatic bile ducts (1/13, P = .009), and none in duodenal adenocarcinomas (0/5, P = .070). PODXL-1 expression was seen in only 9% of hepatocellular carcinomas (5/56, P < .001), 9% (4/47, P < .001) of gastric carcinomas, 10% of esophageal adenocarcinomas (2/20, P = .003), and 6% of colonic adenocarcinomas (1/17, P = .001). When used as a differential diagnostic marker, ampullary carcinoma needs to be excluded, as 30% (6/20, P = .24) of ampullary carcinomas stain positive, especially those of the signet-ring type (3/3). Adenocarcinomas of the lung and prostate, and liver metastases of colorectal carcinomas lacked PODXL-1 expression. It is concluded that immunoreactivity for PODXL-1 favors a pancreatic origin if ampullary carcinoma is excluded.

Tumor necrosis factor alpha- and inducible nitric oxide synthase-producing dendritic cells are rapidly recruited to the bladder in urinary tract infection but are dispensable for bacterial clearance

The role of dendritic cells (DC) in urinary tract infections (UTI) is unknown. These cells contribute directly to the innate defense against various viral and bacterial infections. Here, we studied their role in UTI using an experimental model induced by transurethral instillation of the uropathogenic Escherichia coli (UPEC) strain 536 into C57BL/6 mice. While few DC were found in the uninfected bladder, many had been recruited after 24 h, mostly to the submucosa and uroepithelium. They expressed markers of activation and maturation and exhibited the CD11b+ F4/80+ CD8- Gr-1- myeloid subtype. Also, tumor necrosis factor alpha (TNF-alpha)- and inducible nitric oxide synthase (iNOS)-producing CD11bINT DC (Tip-DC) were detected, which recently were proposed to be critical in the defense against bacterial infections. However, Tip-DC-deficient CCR2-/- mice did not show reduced clearance of UPEC from the infected bladder. Moreover, clearance was also unimpaired in CD11c-DTR mice depleted of all DC by injection of diphtheria toxin. This may be explained by the abundance of granulocytes and of iNOS- and TNF-alpha-producing non-DC that were able to replace Tip-DC functionality. These findings demonstrate that some of the abundant DC recruited in UTI contributed innate immune effector functions, which were, however, dispensable in the microenvironment of the bladder.

Podocalyxin-like protein 1 expression in primary hepatic tumours and tumour-like lesions

AIMS

The differential diagnosis of benign hepatic lesions and well-differentiated hepatocellular carcinomas can be a challenge, especially in small biopsy specimens. Recently, novel proteins expressed by the neovasculature in hepatocellular carcinoma (HCC) have been identified. The aim of this study was to compare the expression of podocalyxin-like protein 1 (PODXL1), a CD34-related sialomucin, in HCC and benign liver tumours or tumour-like lesions.

METHODS AND RESULTS

Vascular marker expression was examined using tissue microarrays as well as standard paraffin sections from formalin fixed paraffin-embedded liver tissue samples. Expression of PODXL1 was compared with anti-CD34, CD31 and von Willebrand factor VIII staining by immunohistochemistry. PODXL1 is expressed in tumour-associated microvasculature endothelial cells in HCC, as well as in capillarized sinusoidal endothelium of focal nodular hyperplasia (FNH) and hepatic adenoma. Expression in cirrhotic nodules correlates with CD34 and highlights endothelium in the inflow area. In dysplastic nodules CD34 and PODXL1 are not or only focally expressed.

CONCLUSIONS

Expression patterns of CD34 and PODXL1 are almost identical in primary hepatic tumours and tumour-like lesions. The presence of CD34+ and PODXL1+ sinusoidal endothelial cells aids in the diagnosis of HCC. Sinusoidal expression of PODXL1 is also seen in a less diffuse pattern in FNH and adenoma.

Rapid growth of invasive metastatic melanoma in carcinogen-treated hepatocyte growth factor/scatter factor-transgenic mice carrying an oncogenic CDK4 mutation

Currently, novel mouse models of melanoma are being generated that recapitulate the histopathology and molecular pathogenesis observed in human disease. Impaired cell-cycle control, which is a hallmark of both familial and sporadic melanoma, promotes slowly growing carcinogen-induced melanomas in the skin of mice carrying a mutated cyclin-dependent kinase 4 (CDK4(R24C)). Deregulated receptor tyrosine kinase signaling, which is another important feature of human melanoma, leads to spontaneous development of metastatic melanoma after a long latency period in mice overexpressing hepatocyte growth factor/scatter factor (HGF/SF mice). Here we report that treatment with 7,12-dimethylbenz[a]anthracene and 12-O-tetradecanoylphorbol-13-acetate induced metastatic melanomas in all HGF/SF mice on the C57BL/6 background, which histologically resemble human melanoma. Importantly, mutant CDK4 dramatically increased the number and the growth kinetics of carcinogen-induced primary melanomas in the skin and promoted the growth of spontaneous metastases in lymph nodes and lungs in all HGF/SF mice within the first 3 months of life. Apart from very few skin papillomas, we did not observe tumors of other histology in carcinogen-treated HGF/SF x CDK4(R24C) mice. This new experimental mouse model can now be exploited to study further the biology of melanoma and evaluate new treatment modalities.

Primary intrahepatic malignant mesothelioma of epithelioid type

A case of epithelioid mesothelioma presenting as a primary intrahepatic tumor is described. The patient was a 62-year-old man with a 5.8-cm intrahepatic mass on an incidental intra-abdominal CT scan. Thorough clinical and radiographic examination did not reveal any evidence of tumor elsewhere. Macroscopic and microscopic examination demonstrated an intrahepatic tumor consisting of tubular and papillary proliferations of large epithelioid cells, surrounded by a densely mixed inflammatory infiltrate. The tumor cells were strongly positive for pancytokeratin, CK7, CA-12.5, and calretinin, as well as D2-40, and were faintly positive for thrombomodulin and vimentin. The proliferative rate was focally increased up to 20% by Ki-67 staining and the tumor expressed focally p53. Ultrastructurally, numerous microvilli on the cell surface, and abundant desmosomal plaques, characteristic of mesothelial cells, were found. To date, this is the third reported case of a primary intrahepatic mesothelioma.

CD56 expression aids in the differential diagnosis of cholangiocarcinomas and benign cholangiocellular lesions

CD56 (neuronal cell adhesion molecule, N-CAM) has been reported in neuroendocrine tumours and as a marker of reactive biliary epithelial cells. However, up to date, it is not used to distinguish malignant from non-malignant biliary lesions. In this study, we systematically examined CD56 expression on 98 tumours arising from the biliary tree as well as intrahepatic conditions with reactive neoductules. When neuroendocrine carcinomas are excluded, only 4 of 32 (12.5%) cholangiocarcinomas expressed CD56, 2 of which showed clear cell morphology. Reactive bile ductules adjacent to cirrhotic nodules as well as in focal nodular hyperplasia were CD56 positive. Twelve of 17 (70.5%) bile duct adenomas were CD56 positive, whereas von Meyenburg complexes expressed CD56 only very focally in less than 5% of lesional cells. Bile duct cysts were negative for CD56 with the exception of focally interspersed neuroendocrine cells, similar to that seen in segmental bile ducts. Thus, if van Meyenburg complexes are excluded, CD56 can be used to differentiate intrahepatic non-neoplastic from neoplastic proliferations, which is a helpful diagnostic tool in small liver biopsies.

The role of cytotoxic skin-homing CD8+ lymphocytes in cutaneous cytotoxic T-cell lymphoma and pityriasis lichenoides

BACKGROUND

Pityriasis lichenoides (PL) is a rare cutaneous lymphoproliferative disorder of unknown origin. Malignant transitions of PL have been described, but are very rare. We recently observed the fatal course of a 26-year-old patient who presented with a clinical picture resembling PL but had cytotoxic CD8+ T-cell lymphoma of the skin (CxCTL). This case prompted us to reinvestigate the role of cytotoxic T lymphocytes in PL and its relationship to antiviral immunity.

METHODS

Skin biopsy specimens of 11 patients with PL and two biopsy specimens of CxCTL were included. In all, 5 biopsy specimens taken from healthy skin and 5 samples of varicella-zoster virus (VZV) skin lesions were analyzed for control purposes. The inflammatory infiltrate was characterized by immunohistochemistry using monoclonal antibodies against CD3, CD4, CD8, CD20, cutaneous lymphocyte-associated antigen (CLA), CCR4, CXCR3, Granzyme B, Tia-1, and MxA. Flow cytometry was used to analyze the expression of chemokine receptors on peripheral blood mononuclear cells in CxCTL.

RESULTS

The CxCTL skin lesions were dominated by a dense infiltration of CD8+ cytotoxic lymphocytes with a skin-homing CLA+ CCR4+ phenotype. PL and VZV skin lesions were also characterized by a predominantly CD8+ T cellular infiltrate with strong expression of the cytotoxic molecules Granzyme B and Tia-1 and the skin-homing molecules CLA and CCR4. Coexpression analyses confirmed that skin CLA+ CD8+ cytotoxic T cells are present in CxCTL, VZV, and PL skin lesions. Strong lesional production of the antiviral protein MxA, which is specifically induced by type I interferons, could be found in all investigated disorders. The study was based on histologic, immunohistologic, and flow cytometric analyses in a limited number of patients, because of the rareness of the investigated diseases.

CONCLUSION

Our results revealed a striking similarity between the immunohistologic picture of malignant CxCTL, benign PL, and VZV skin lesions. Strong expression of the antiviral protein MxA in all disorders supports the view that a common antiviral immune response pattern leads to aberrant skin recruitment of CLA+ CCR4+ cytotoxic T lymphocytes in PL and CxCTL.

Array-based comparative genomic hybridization reveals recurrent chromosomal aberrations and Jab1 as a potential target for 8q gain in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the major malignancies worldwide. We have previously characterized global gene expression patterns in HCC using microarrays. Here, we report the analysis of genomic DNA copy number among 49 HCC samples using BAC array-based comparative genomic hybridization (CGH). We observed recurrent and characteristic chromosomal aberrations, including frequent DNA copy number gains of 1q, 6p, 8q and 20q, and losses of 4q, 8p, 13q, 16q and 17p. We correlated gene expression with array CGH data, and identified a set of genes whose expression levels correlated with common chromosomal aberrations in HCC. Especially, we noticed that high expression of Jab1 in HCC significantly correlated with DNA copy number gain at 8q. Quantitative microsatellite analysis further confirmed DNA copy number gain at the Jab1 locus. Overexpression of Jab1 in HCC was also validated using real-time RT-PCR, and Jab1 protein levels were studied by immunohistochemistry on tissue microarrays. Functional analysis in HCC cell lines demonstrated that Jab1 may regulate HCC cell proliferation, thereby having a potential role in HCC development. In conclusion, this study shows that array-based CGH provides high resolution mapping of chromosomal aberrations in HCC, and demonstrates the feasibility of correlating array CGH data with gene expression data to identify novel oncogenes and tumor suppressor genes.

A blood-borne antigen induces rapid T-B cell contact: a potential mechanism for tolerance induction

Understanding the difference between the development of a productive T-cell response and tolerance is central to discerning how the immune system functions. Intravenous injection of soluble protein is thought to mimic the presentation of self-serum and orally introduced antigens. It is generally toleragenic. The current view is that this outcome reflects the failure of 'immunogenic' dendritic cells to relocate to the T-cell zone of the secondary lymphoid tissues. Here, using a peptide/I-Ek tetramer and antibodies to stain splenic sections, we showed that antigen-specific T cells were activated in the spleen within hours of injection or feeding of protein. The activated T cells were found to be located at the T-B junction, the bridging zone and the B-cell area, interacting directly with B cells. In addition, B cells gain the ability to present antigen. Our results suggest a way for T cells to be stimulated by blood-borne antigen presented by naïve B cells, a potential mechanism of tolerance induction.

Induction of rapid T cell activation and tolerance by systemic presentation of an orally administered antigen

To understand how orally introduced antigen regulates peripheral immune responses, we fed cytochrome c protein to mice transgenic for the beta chain of a cytochrome c-specific TCR and followed the antigen-specific T cell responses with a cyt c/I-Ek tetramer staining reagent. We find that within 6 hr of cytochrome c administration, antigen-specific systemic T cell activation is induced, and spleen cells gain the ability to stimulate cytochrome c-specific T cell responses. Feeding multiple low doses of cytochrome c down-regulates the systemic immune response, which can be correlated with a reduction of antigen-specific T cells and not with immune deviation. These results suggest that systemic distribution of antigen contributes significantly to oral tolerance induction.

Early biochemical signals arise from low affinity TCR-ligand reactions at the cell-cell interface

The kinetics of acid release by a mixture of T cells and antigen presenting cells were measured with a microphysiometer during a brief exposure to antigenic peptides. We find that some of the early biochemical events that lead to cellular proliferation cause a specific increase in the rate of acid release. The duration of this increase in acid release reflects the life-time of the peptide-MHC complexes. Peptides that form long-lived complexes produce a response that is stable for more than an hour. Serial TCR engagement is suggested by the observation that the amplitude of this stable response can be rapidly shifted up or down with additional agonist peptide or with antibodies that block T cell receptor binding. Cells briefly exposed to a peptide that forms short-lived peptide-MHC complexes produce a response that decays rapidly as peptide is washed away. A quantitative analysis of the kinetics of this decay in acidification demonstrates that intercellular TCR-ligand reactions are rapid, reversible, and of low apparent affinity with < 20% of peptide-MHC ligand bound to a TCR at any one time. These results demonstrate that the fraction of peptide-MHC ligands bound to TCRs at the cell-cell interface is no higher than anticipated from the affinities observed in solution for isolated TCRs and ligands.

Transforming growth factor beta 1 regulates tissue inhibitor of metalloproteinases-1 expression in differentiated human articular chondrocytes

OBJECTIVE

To investigate the role of interleukin-6 (IL-6) and transforming growth factor beta 1 (TGF beta 1) in the regulation of tissue inhibitor of metalloproteinases-1 (TIMP-1) synthesis in human articular chondrocytes.

METHODS

Articular cartilage was obtained from human knee joints 24 hours after death. Chondrocytes were isolated by collagenase digestion and embedded in low-gelling-temperature agarose. After stimulation by cytokines, total RNA was isolated and analyzed by Northern blotting. TIMP-1 protein levels were determined using a competitive enzyme-linked immunosorbent assay.

RESULTS

Human chondrocytes in agarose culture expressed messenger RNA (mRNA) for the IL-6 receptor (gp80) and its signal-transducing subunit gp130. In contrast to the findings in a previous study, IL-6 did not stimulate TIMP-1 expression in these cells, whereas TGF beta 1 was an important inducer of TIMP-1 mRNA and protein synthesis.

CONCLUSION

Our findings suggest that TGF beta 1 has a protective effect on the extracellular matrix of human articular chondrocytes.