Frequent protein kinase A regulatory subunit A1 mutations but no GNAS mutations as potential driver in sporadic cardiac myxomas

PURPOSE

Cardiac myxomas (CMs) are the second most common benign primary cardiac tumors, mainly originating within the left atrium. Approximately 5% of CM cases are associated with Carney Complex (CNC), an autosomal dominant multiple neoplasia syndrome often caused by germline mutations in the protein kinase A regulatory subunit 1A (PRKAR1A). Data concerning PRKAR1A alterations in sporadic myxomas are variable and sparse, with PRKAR1A mutations reported to range from 0% to 87%. Therefore, we investigated the frequency of PRKAR1A mutations in sporadic CM using next-generation sequencing (NGS). Additionally, we explored mutations in the catalytic domain of the Protein Kinase A complex (PRKACA) and examined the presence of GNAS mutations as another potential driver.

METHODS AND RESULTS

This study retrospectively collected histological and clinical data from 27 patients with CM. First, we ruled out the possibility of underlying CNC through clinical evaluations and standardized interviews for each patient. Second, we performed PRKAR1A immunohistochemistry (IHC) analysis and graded the reactivity of myxoma cells semi-quantitatively. NGS was then applied to analyze the coding regions of PRKAR1A, PRKACA, and GNAS in all 27 cases. Of the 27 sporadic CM cases, 13 (48%) harbored mutations in PRKAR1A. Among these 13 mutant cases, six displayed more than one mutation in PRKAR1A. Most of the identified mutations resulted in premature stop codons or affected splicing. In PRKAR1A mutant CM cases, the loss of PRKAR1A protein expression was significantly more common. In two cases with missense mutations, protein expression remained preserved. Furthermore, a single mutation was detected in the catalytic domain of the protein kinase A complex, while no GNAS mutations were found.

CONCLUSION

We identified a relatively high frequency of PRKAR1A mutations in sporadic CM. These PRKAR1A mutations may also represent an important oncogenic mechanism in sporadic myxomas, as already known in CM cases associated with CNC.

Establishing safe high hydrostatic pressure devitalization thresholds for autologous head and neck cancer vaccination and reconstruction

High hydrostatic pressure specifically devitalizes cells and tissues without major changes in their molecular structure. Hence, high hydrostatic pressure may enhance the development of whole-cell anti-tumor vaccines, representing tumor heterogeneity and thus (neo-) antigen diversity. Moreover, safe devitalization of tumor-infiltrated supporting tissue may facilitate reimplantation for functional reconstruction. However, precise high hydrostatic pressure thresholds for safe cancer cell killing are unknown. Here, we show that high hydrostatic pressure of at least 450 MPa is necessary to safely devitalize head and neck squamous cell cancer. A pressure of 300 MPa, which has been used frequently in cancer vaccine preparation, resulted in partial devitalization with 27% live cells in flow cytometry and 4% remaining autofluorescence in cell culture after one week. The remaining cells could form vital tumors in the chorioallantoic membrane assay. In contrast, 450 MPa killed all cells in vitro and prevented tumor outgrowth in ovo. The effectiveness of 450 MPa was attributed to the induction of DNA double-strand breaks, independent of apoptosis, autophagy, or methuosis. Furthermore, 450 MPa continued to induce immunogenic cell death. Our results demonstrate that 450 MPa of high hydrostatic pressure induces safe and sustained devitalization of head and neck cancer cells and tissues. Because of the heterogeneity in pressure resistance, we propose our approach as a starting point for determining the precise thresholds for other cancer entities. Further studies on head and neck cancer should focus on immunological co-cultures, combinations of immune checkpoint inhibition, and accurate anatomical reconstruction with pressure-treated autografts.

ERBB2 Amplification as a Predictive and Prognostic Biomarker in Upper Tract Urothelial Carcinoma

Upper tract urothelial carcinomas (UTUCs) occur in about 5-10% of all urothelial carcinomas and are frequently discovered in high-stage disease. We aimed to evaluate human epidermal growth factor receptor 2 (ERBB2) protein expression immunohistochemically and ERBB2 amplification in UTUCs by fluorescence in situ hybridization, applying a tissue microarray technique. ERBB2 overexpression and ERBB2 amplification were defined according to the recommendations of the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) for breast cancer and gastric carcinoma (GC), revealing scores of 2+ and 3+ in 10.2% and 41.8% of UTUCs, respectively. The performance parameters showed obviously higher sensitivity of ERBB2 immunoscoring according to the ASCO/CAP criteria for GC. ERBB2 amplification was detected in 10.5% of UTUCs. ERBB2 overexpression was more likely to be found in high-grade tumors and was associated with tumor progression. Univariable Cox regression analysis revealed a significantly lower progression-free survival (PFS) in cases with ERBB2 immunoscores of 2+ or 3+ according to the ASCO/CAP guidelines for GC. UTUCs with ERBB2 amplification showed a significantly shorter PFS in the multivariable Cox regression analysis. Irrespective of their ERBB2 status, patients with UTUC treated with platin showed a significantly lower PFS than UTUC patients who had not received any platin-based therapy. In addition, UTUC patients with a normal ERBB2 gene status who had not received platin-based therapy showed significantly longer overall survival. The results suggest that ERBB2 is a biomarker for progression in UTUCs and may define a distinct subgroup of UTUCs. As previously shown, ERBB2 amplification is infrequent. However, the small number of patients diagnosed with ERBB2-amplified UTUC might benefit from ERBB2-targeted cancer therapy. In clinical-pathological routine diagnostics, the determination of ERBB2 amplification is an established method in some defined entities and also successful in small samples. Still, the simultaneous use of ERBB2 immunohistochemistry and ERBB2 in situ hybridization would be important in order to record the low rate of amplified UTUC cases as completely as possible.

The miR-183/96/182 cluster is upregulated in glioblastoma carrying EGFR amplification

Glioblastoma (GBM) is one of the most frequent primary brain tumors. Limited therapeutic options and high recurrency rates lead to a dismal prognosis. One frequent, putative driver mutation is the genomic amplification of the oncogenic receptor tyrosine kinase EGFR. Often accompanied by variants like EGFRvIII, heterogenous expression and ligand independent signaling render this tumor subtype even more difficult to treat, as EGFR-directed therapeutics show only weak effects at best. So EGFR-amplified GBM is considered to have an even worse prognosis, and therefore, deeper understanding of molecular mechanisms and detection of potential targets for novel therapeutic strategies is urgently needed. In this study, we looked at the level of microRNAs (miRs), small non-coding RNAs frequently deregulated in cancer, both acting as oncogenes and tumor suppressors. Comparative analysis of GBM with and without EGFR amplification should give insight into the expression profiles of miRs, which are considered both as potential targets for directed therapies or as therapeutic reagents. Comparison of miR profiles of EGFR-amplified and EGFR-normal GBM revealed an upregulation of the miR-183/96/182 cluster, which is associated with oncogenic properties in several tumor entities. One prominent target of this miR cluster is FOXO1, a pro-apoptotic factor. By observing FOXO1 downregulation in EGFR-amplified tumors, we can see a significant correlation of EGFR amplification, miR-183/96/182 cluster upregulation, and repression of FOXO1. Although no significant difference in overall survival is shown, these data may contribute to the molecular understanding of this tumor subtype and offer potential targets for miR-based therapies.

Preclinical Head and Neck Squamous Cell Carcinoma Models for Combined Targeted Therapy Approaches

This study aimed to refine combined targeted approaches on well-characterized, low-passage tumor models. Upon in vivo xenografting in immunodeficient mice, three cell lines from locally advanced or metastatic HNSCC were established. Following quality control and basic characterization, drug response was examined after therapy with 5-FU, Cisplatin, and cyclin-dependent kinase inhibitors (abemaciclib, THZ1). Our cell lines showed different in vitro growth kinetics, morphology, invasive potential, and radiosensitivity. All cell lines were sensitive to 5-FU, Cisplatin, and THZ1. One cell line (HNSCC48 P0 M1) was sensitive to abemaciclib. Here, Cyto-FISH revealed a partial CDKN2a deletion, which resulted from a R58* mutation. Moreover, this cell line demonstrated chromosome 12 polysomy, accompanied by an increase in CDK4-specific copy numbers. In HNSCC16 P1 M1, we likewise identified polysomy-associated CDK4-gains. Although not sensitive to abemaciclib per se, the cell line showed a G1-arrest, an increased number of acidic organelles, and a swollen structure. Notably, intrinsic resistance was conquered by Cisplatin because of cMYC and IDO-1 downregulation. Additionally, this Cisplatin-CDKI combination induced HLA-ABC and PD-L1 upregulation, which may enhance immunogenicity. Performing functional and molecular analysis on patient-individual HNSCC-models, we identified CDK4-gains as a biomarker for abemaciclib response prediction and describe an approach to conquer intrinsic CDKI resistance.

Establishment and characterization of patient-derived head and neck cancer models from surgical specimens and endoscopic biopsies

Background

Head and neck squamous cell carcinoma (HNSCC) is heterogeneous in etiology, phenotype and biology. Patient-derived xenografts (PDX) maintain morphology and molecular profiling of the original tumors and have become a standard “Avatar” model for human cancer research. However, restricted availability of tumor samples hindered the widespread use of PDX. Most PDX-projects include only surgical specimens because reliable engraftment from biopsies is missing. Therefore, sample collection is limited and excludes recurrent and metastatic, non-resectable cancer from preclinical models as well as future personalized medicine.

Methods

This study compares the PDX-take rate, -growth, histopathology, and molecular characteristics of endoscopic specimens with surgical specimens. HNSCC samples (n = 55) were collected ad hoc, fresh frozen and implanted into NOD.Cg-Prkdc^scidIl2rg^tm1Wjl/SzJ mice.

Results

Engraftment was successful in both sample types. However, engraftment rate was lower (21 vs. 52%) and growth delayed (11.2 vs. 6.7 weeks) for endoscopic biopsies. Following engraftment, growth kinetic was similar. Comparisons of primary tumors and corresponding PDX models confirmed preservation of histomorphology (HE histology) and molecular profile (Illumina Cancer Hotspot Panel) of the patients’ tumors. Accompanying flow cytometry on primary tumor specimens revealed a heterogeneous tumor microenvironment among individual cases and identified M2-like macrophages as positive predictors for engraftment. Vice versa, a high PD-L1 expression (combined positive score on tumor/immune cells) predicted PDX rejection.

Conclusion

Including biopsy samples from locally advanced or metastatic lesions from patients with non-surgical treatment strategies, increases the availability of PDX for basic and translational research. This facilitates (pre-) clinical studies for individual response prediction based on immunological biomarkers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02047-w.

Ceruloplasmin expression in renal cell carcinoma correlates with higher-grade and shortened survival

Aim: We aimed to explore ceruloplasmin (CP) expression in clear cell renal cell carcinoma (ccRCC). Materials & methods: CP was analyzed in biofluid samples of 63 ccRCC patients, divided into three grading groups, and immunohistochemically, in 308 ccRCC. Results: Significant differences of mean plasma and urine CP levels in different grading groups were found. CP immunoreactivity was significantly linked to high-grade disease. Log rank tests showed a significant shorter overall survival rate in CP-positive cases (all p < 0.05). Conclusion: CP protein levels in biofluid samples confirmed differential CP expressions, depending on nuclear grade in ccRCC as previously seen in RNA expression analysis. CP expression was linked to high-grade disease and reduced survival rate in RCC.

Histopathological Features and Ann Arbor Stage in Periocular Lymphoma

BACKGROUND

To evaluate biodata, symptoms/signs, lymphoma type, localization, stage level, treatment choice and outcome of ocular adnexal lymphoma (OAL).

PATIENTS AND METHODS

A single-center retrospective analysis of 56 patients with OAL was performed from 1998 to 2018.

RESULTS

OAL involved the orbit in 44.6%, the conjunctiva in 32.1%, the lacrimal apparatus in 14.3% and the eyelid in 8.93%. Extranodal marginal zone B-cell lymphoma (EMZL) was found in 60.7%, follicular lymphoma (FL) in 21.4%, diffuse large B-cell lymphoma in 7.14%, mantle cell lymphoma in 5.36% and chronic lymphatic leukaemia in 5.36% patients. No relapse was seen in 76%. EMZL and FL had a significantly better overall survival compared to other lymphoma types (p=0.002). Patients with Ann Arbor stage IE had a significantly better prognosis than those with stages higher than IE (p=0.048).

CONCLUSION

Our data suggest that clinicopathological features such as Ann Arbor stage influence survival.

Surgery for Valvular and Nonvalvular Papillary Fibroelastomas

Papillary fibroelastomas (PFE) are benign neoplasms, mostly located on valvular surfaces with high embolic potential. This study presents a 27-year single institutional experience on surgical treatment of PFE in an adult patient- cohort with long-term follow-up. This study was approved by the institutional review board. Date and number of IRB approval: 11/23/2017, Institutional Review Board approval number A2014-0149. The need for individual patient consent was waived. We retrospectively evaluated all patients who underwent cardiac surgery for suspected space-occupying lesions in the observation period between June 1991 and June 2018 at our hospital. Clinicopathological features, imaging characteristics, surgical procedures and disease outcome were analyzed. 120 patients were diagnosed with various primary/secondary cardiac tumors and histology confirmed 21 PFEs were found in 16 patients. There was no significant age difference between patients with valvular vs nonvalvular PFEs (P = 0.26). Valvular lesions were found in aortic valve (n = 6), mitral valve (n = 2) and tricuspid valve (n = 1). Nonvalvular PFEs were found in right atrium (n = 2), left ventricle (n = 2), left atrial appendage (n = 2) and aortic wall (n = 1). Valvular lesions were significantly smaller in size compared to non-valvular lesions (P = 0.0013). Left-side PFEs were associated with a high embolization episodes (10/13 patients, 77%) not related to the size. One patient died in-hospital. All other patients were discharged out of the hospital postoperative. Follow-up was performed regularly for a median of 2.8 years (range 0.1-11 years) postoperative. Nonvalvular PFE tended to be larger in size and at least when located on the left sided heart had equally high propensity to embolize compared to valvular PFE. We strongly advocate surgical excision in all left-sided PFE.

Papillary Fibroelastoma in Differential Diagnosis of Left Atrial Appendage Masses

Papillary fibroelastomas are benign tumors that usually originate from cardiac valves but may have other endocardial origins. We report the cases of 2 patients in whom left atrial appendage masses were initially diagnosed as thrombus. They were treated for embolic stroke and their symptoms resolved; however, their left atrial appendage masses did not regress. After surgery, histologic analysis of the resected masses revealed papillary fibroelastoma in both cases. We discuss the diagnostic and therapeutic dilemmas encountered in patients with papillary fibroelastomas and cardiac masses other than thrombus.

Comparative genomic profiling of glandular bladder tumours

Primary glandular bladder tumours (bladder adenocarcinoma [BAC], urachal adenocarcinoma [UAC], urothelial carcinoma with glandular differentiation [UCg]) are rare malignancies with histological resemblance to colorectal adenocarcinoma (CORAD) in the majority of this subgroup. Definite case numbers are very low, molecular data are limited and the pathogenesis remains poorly understood. Therefore, this study was designed to complement current knowledge by in depth analysis of BAC (n = 12), UAC (n = 13), UCg (n = 11) and non-invasive glandular lesions (n = 19). In BAC, in addition to known alterations in TP53, Wnt, MAP kinase and MTOR pathway, mutations in SMAD4, ARID1A and BRAF were identified. Compared to published data on muscle invasive bladder cancer (BLCA) and CORAD, UCg exhibited frequent "urothelial" like alterations while BAC and UAC were characterised by a more "colorectal" like mutational pattern. Immunohistochemically, there was no evidence of DNA mismatch repair deficiency or PD-L1 tumour cell positivity in any sample. Depending on the used antibody 0-45% of BAC, 0-30% of UCg and 0% UAC cases exhibited PD-L1 expressing tumour associated immune cells. A single BAC (9%, 1/11) showed evidence of ARID1A protein loss, and two cases of UCg (20%, 2/10) showed loss of SMARCA1 and PBRM1, respectively. Taken together, our data suggest at least in part involvement of similar pathways driving tumourigenesis of adenocarcinomas like BAC, UAC and CORAD independent of their tissue origin. Alterations of TERT and FBXW7 in single cases of intestinal metaplasia further point towards a possible precancerous character in line with previous reports.

Loss of Mismatch-repair Protein Expression and Microsatellite Instability in Upper Tract Urothelial Carcinoma and Clinicopathologic Implications

BACKGROUND

Upper tract urothelial carcinoma (UTUC) may arise in the setting of hereditary non-polyposis colorectal cancer (Lynch syndrome [LS]) or sporadically. Variable frequencies of microsatellite instability (MSI) were found in UTUC. For advanced solid MSI tumors, targeted therapy with programmed death-ligand 1 inhibitors is available. Therefore, we aimed to determine the prevalence of mismatch repair (MMR) protein loss and MSI in UTUC using a tissue microarray approach and further molecular and correlation analysis.

MATERIALS AND METHODS

We studied the immunohistochemical expression of MLH1, MSH2, MSH6, and PMS2 on tissue microarrays containing formalin-fixed, paraffin-embedded samples of 128 patients with UTUC. MSI analysis was performed in 79 cases with deficient MMR protein expression, and/or in patients aged 60 years and below, and/or other tumors possibly related to LS.

RESULTS

Loss of MMR protein expression was seen in 24 (18.8%) of 128 cases. MSI analysis revealed MSI-high in 29, MSI-low in 7 cases. The Fisher exact test demonstrated significant differences between MSI and loss of MMR protein expression, clinically possible LS, tumor growth pattern, inverted growth pattern, and death (P < .001, P < .001, P = .002, P = .003, and P = .033, respectively). MSI does not appear to influence survival (overall and progression-free), but there was a significant shorter progression-free survival in MSI-high versus MSS patients who had received chemotherapy.

CONCLUSION

The frequency of MSI in UTUC was 36 (28.1%) of 128 patients with a good accuracy of immunohistochemistry. In daily practice, MSI screening especially is recommended in patients with advanced UTUC and inverted papillary tumor growth pattern with the aim of screening patients for possible targeted therapy.

Activation of the Kynurenine Pathway in Human Malignancies Can Be Suppressed by the Cyclin-Dependent Kinase Inhibitor Dinaciclib

Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO2) are the key enzymes of tryptophan (TRP) metabolism in the kynurenine pathway (KP). Both enzymes function as indicators of immunosuppression and poor survival in cancer patients. Direct or indirect targeting of either of these substances seems thus reasonable to improve therapy options for patients. In this study, glioblastoma multiforme (GBM) as well as head and neck squamous cell carcinomas (HNSCC) were examined because of their different mechanisms of spontaneous and treatment-induced immune escape. Effects on gene expression and protein levels were examined. Accompanying assessment of TRP metabolites from treated GBM cell culture supernatants was conducted. Our results show a heterogeneous and inversely correlated expression profile of TRP-metabolizing genes among GBM and HNSCC cells, with low, but inducible IDO1 expression upon IFNγ treatment. TDO2 expression was higher in GBM cells, while genes encoding kynurenine aminotransferases were mainly confined to HNSCC cells. These data indicate that the KP is active in both entities, with however different enzymes involved in TRP catabolism. Upon treatment with Temozolomide, the standard of care for GBM patients, IDO1 was upregulated. Comparable, although less pronounced effects were seen in HNSCC upon Cetuximab and conventional drugs (i.e., 5-fluorouracil, Gemcitabine). Here, IDO1 and additional genes of the KP (KYAT1, KYAT2, and KMO) were induced. Vice versa, the novel yet experimental cyclin-dependent kinase inhibitor Dinaciclib suppressed KP in both entities. Our comprehensive data imply inhibition of the TRP catabolism by Dinaciclib, while conventional chemotherapeutics tend to activate this pathway. These data point to limitations of conventional therapy and highlight the potential of targeted therapies to interfere with the cells' metabolism more than anticipated.

[Inverted In Vitro Confocal Microscopy in Mycotic Keratitis with Corneal Endothelial Epithelial Decompensation]

The sensitivity of confocal microscopy ranges between 80 and 90% and thus lies above the sensitivity of pathogen identification by microbiological culture. Typically, in vivo confocal microscopy enables us to diagnose mycotic keratitis non-invasively and atraumatically on the day of admission. Herein we present a patient with an ulcer on a corneal graft, pronounced corneal endothelial epithelial decompensation and a retrocorneal fungal adhesion after repeat-keratoplasty 5 years ago - due to chronic graft rejection after keratoplasty for Fuchs endothelial corneal dystrophy. Clinically there was a suspicion of fungal keratitis. Conventional en face confocal microscopy, however, did not detect hyphae. Due to the pronounced corneal endothelial epithelial decompensation, we were able to detect the fungal hyphae only after repeat penetrating keratoplasty by means of inverted in vitro confocal microscopy on the day of surgery. Histology confirmed the diagnosis of keratomycosis.

[Mediastinal Lymphadenopathy - Tuberculosis or Tularemia?]

Anamnese und klinischer Befund Ein 67-jähriger Patient entwickelte akute Kopfschmerzen, nach 2 Tagen zusätzlich Schüttelfrost und Fieber. Ein Infektfokus konnte nicht gefunden werden, periphere Lymphknoten waren nicht palpabel.

Untersuchungen und Diagnose Nach 2 Wochen wurden in einer 18F-FDG-PET-Computertomografie multiple mediastinale, supraklavikuläre und axilläre Lymphknotenschwellungen gesehen. Histologisch zeigten sich epitheloidzellige Granulome mit zentraler Nekrose. Tuberkulose wurde immunologisch und mikrobiologisch ausgeschlossen. Serologisch wurde eine akute Tularämie diagnostiziert.

Therapie und Verlauf Unter der Therapie mit Ciprofloxacin für 20 Tage kam es zum Abklingen der Kopfschmerzen und Normalisierung der Entzündungsparameter.

Folgerung Infektionsquelle war das Einatmen erregerhaltigen Staubs beim Herausreißen einer Efeuhecke 2 Tage vor Symptombeginn. Die Tularämie (Hasenpest) ist eine Zoonose, die direkt von infizierten Tieren oder indirekt über Zecken und Mücken, inhalativ durch Einatmen von kontaminiertem Staub oder durch Ingestion von kontaminiertem Wasser übertragen werden kann. Beim histologischen Nachweis epitheloidzelliger Granulome mit Nekrosen ist die Tularämie eine seltene Differenzialdiagnose.

Ultrastructural findings in graft failure after Descemet membrane endothelial keratoplasty (DMEK) and new triple procedure

To investigate factors that influence graft failure after Descemet membrane endothelial keratoplasty (DMEK) based on transmission electron microscopy results.Retrospective observational case series.This single center study included 16 eyes of 16 patients with penetrating keratoplasty (n = 14) or repeat DMEK (n = 2) following graft failure after DMEK. The main outcome measures were ultrastructural changes in the explanted graft on transmission electron microscopy, best-corrected visual acuity, and central corneal thickness.The mean preoperative and postoperative best-corrected visual acuity was 1.01 ± 0.54 logMAR and 0.56 ± 0.37 logMAR. The mean central corneal preoperative and postoperative thickness was 667 ± 187 μm and 511 ± 42 μm. Visual acuity and central corneal thickness improved significantly (P = .001/P = .003) after repeat surgery. Electron microscopy showed that 3 of 14 corneas showed upside down transplantation, and 3 corneas had pigmented cells or pigment granules at the Descemet-stroma interface. Further, 9 of 16 specimens showed a posterior collagenous layer deposited onto the Descemet membrane (average thickness 5.1 ± 6.2 μm; ranged 0.65-20 μm); this did not correlate significantly with the time between the original and repeat keratoplasty. Of 16 original grafts, 7 showed ultrastructural anomalies of the Descemet membrane, but one excised cornea showed no Descemet membrane pathologies.The majority of eyes with graft failure after DMEK showed ultrastructural changes in the Descemet membrane. It is crucial to assess donor tissue quality and to conduct graft marking before surgery to avoid immediate or delayed graft failure after DMEK. Nevertheless, repeat keratoplasty provided significant improvement in central corneal thickness and visual acuity.

Keratoconus-like tomographic changes in a case of recurrent interstitial keratitis

Background

The purpose of this report was to describe a single case of recurrent interstitial keratitis in a young patient leading to keratoconus-like corneal changes.

Results

Over the 2 years follow-up, the patient developed clinical signs of keratoconus with Vogt’s striae, Fleischer Ring and paracentral stromal thinning in the affected eye only. The tomographic measurements revealed a rapid reduction of corneal thickness from 581 to 303 μm and an irregular steepening of the pathological cornea. True net corneal power increased from 42.8 to 48.8 dioptres (D) and maximal power of the anterior surface from 44.9 to 66.9 D. Best-corrected visual acuity (BCVA) decreased from 20/20 to 20/200. A penetrating excimer laser keratoplasty was performed to restore vision and corneal stability.

Conclusion

Keratoconus-like changes can occur in young patients with recurrent interstitial keratitis and request corneal transplantation.

Expression and clinicopathological correlations of retinoid acid receptor responder protein 1 in renal cell carcinomas

AIM

To evaluate the expression and prognostic value of RARRES1 at protein level in renal cell carcinoma (RCC).

MATERIALS & METHODS

Expression profile of RARRES1 was analyzed in 903 documented RCC followed by clinicopathological correlations and survival analysis.

RESULTS

RARRES1 expression was seen in 72.5% of RCC. A stronger RARRES1 expression was seen in high grade compared with low grade RCC (p < 0.001). Logrank tests revealed shorter overall survival in RARRES1 positive RCC (p = 0.006) and in pT1/2 tumors with RARRES1 expression (p = 0.002).

CONCLUSION

The variable expression profile in low and high grade RCC may reflect and confirm the differences of previous gene expression analysis. There was a significant prognostic value of RARRES1 expression in patients with RCC, especially in pT1/2 tumors.

Ectopic Spleen Tissue - an Underestimated Differential Diagnosis of a Hypervascularised Liver Tumour

Background

Patients with liver cirrhosis have an increased risk of developing hepatocellular carcinoma (HCC). Implantation metastasis following diagnostic biopsy is a well-known complication. Therefore, primary resection of a hypervascularised tumour suspicious for HCC is often performed with curative intent.

Case Report

An exophytically growing mass was diagnosed between liver segments III and IVb by means of ultrasound in a 53-year old male patient with decompensated liver cirrhosis. Computed tomography confirmed a 3.5 cm large hypervascularised tumour with given resectability. Intraoperatively, the tumour appeared like a HCC. Thus, an atypical resection was performed. Histopathology revealed ectopic spleen tissue without any signs of malignancy. As enquiries revealed, the patient had undergone splenectomy after a blunt abdominal trauma 9 years prior to admission.

Conclusion

In the present patient, hepatic splenosis in a cirrhotic liver was misinterpreted as HCC. In patients with a history of traumatic rupture of the spleen or splenectomy, splenosis has to be considered as a potential differential diagnosis of a hypervascularised tumour. Specific diagnostics should be performed to rule out splenosis.

Arthralgia and blood culture-negative endocarditis in middle Age Men suggest tropheryma whipplei infection: report of two cases and review of the literature

Background

Whipple’s disease is a rare, often multisystemic chronic infectious disease caused by the rod-shaped bacterium Tropheryma whipplei. Very rarely the heart is involved in the process of the disease, leading to culture-negative infective endocarditis. Up to 20 % of all infective endocarditis are blood culture-negative and therefore a diagnostic challenge. We present two unusual cases of culture-negative infective endocarditis encountered in two different patients with prior history of arthralgia. A history of rheumatic arthritis or even a transient arthralgia should put Tropheryma whipplei on the top of differentials in patients of this age group presenting with culture-negative infective endocarditis, especially in cases of therapy resistance to antirheumatic agents.

Case presentation

The first patient was a 55 year-old Caucasian male with culture-negative Whipple-related adhesive pericarditis and endocarditis of the aortic valve. Importantly, the patient reported a 15-year history of therapy resistant sero-negative migratory polyarthritis. Aortic valve endocarditis developed during treatment with tocilizumab. The second patient was a 65-year-old male patient with no prior history of the classic Whipple’s disease who presented with a culture-negative aortic valve endocarditis. His past medical history revealed episodes of transient arthralgia, which he was not treated for however, due to the self-limiting nature of the symptoms. Both patients underwent aortic valve replacement surgery. During surgery, pericardectomy was necessary in the first patient due to adhesive pericarditis. Post surgery both patients were started on long-term treatment with trimetoprim-sulfamethoxazol. At 1-year follow-up of both patients, echocardiographic and clinical assessment revealed no signs of persistent infection. Both men reported negative history of arthralgia during the one year period post surgery.

Conclusion

Tropheryma whipplei culture negative-infective endocarditis is an emerging clinical entity, predominantly found in middle-aged and older men with a history of arthralgia. These data highlight the need for ruling out Whipple’s disease in patients with a history of arthralgia prior to initiation of biological agents in treatment of rheumatoid arthritis. There is also a need to assess for Tropheryma whipplei in all patients with culture- negative infective endocarditis.

Prognostic and diagnostic implications of epithelial cell adhesion/activating molecule (EpCAM) expression in renal tumours: a retrospective clinicopathological study of 948 cases using tissue microarrays

OBJECTIVE

To evaluate the expression and prognostic value of epithelial cell adhesion/activating molecule (EpCAM) in a large set of renal cell carcinomas (RCCs) using a tissue microarray (TMA) approach.

MATERIAL AND METHODS

We studied the immunohistochemical expression and overexpression of EpCAM on TMAs containing formalin-fixed, paraffin-embedded samples of 948 patients with documented renal tumours. EpCAM expression was defined as the presence of a specific membranous staining in >5% of the tumour cells. EpCAM overexpression was specified by calculating a total staining score (score range 0-12) as the product of a proportion score and an intensity score, and defined as a score >4.

RESULTS

Of 948 cases, 927 (97.8%) were evaluable morphologically (haematoxylin and eosin stain). EpCAM expression was found in 233/642 (36.3%), 126/155 (81.3%), 54/68 (78.3%), 17/45 (37.8%), 13/30 (43.3%) of clear-cell RCC, papillary RCC (pRCC), chromophobe RCC (cpRCC), oncocytomas and other unclassified tumour types, respectively. Log-rank tests showed a significantly longer overall survival (OS [P = 0.047]) and a trend of EpCAM expression to be associated with a longer progression-free survival (PFS) in all RCC entities (P = 0.065). EpCAM overexpression was significantly correlated with a better PFS in all RCC subtypes, cpRCC and pRCC (P = 0.011, 0.043 and 0.025, respectively). In multivariate analysis EpCAM overexpression was an independent marker for longer PFS in all RCC entities as well as in high grade RCC (P = 0.009 and P = 0.010, respectively).

CONCLUSIONS

The histological subtypes associated with a high rate of EpCAM expression were cpRCC and pRCC. This retrospective analysis demonstrated a trend towards longer OS and PFS for all major RCC subtypes. EpCAM expression had significant prognostic value in patients with cpRCC and pRCC. Furthermore, EpCAM overexpression in high grade RCC may be a helpful marker for prognostication.

Experimental differentiation of intraocular masses using ultrahigh-field magnetic resonance imaging--a case series

PURPOSE

The case reports presented here were compiled to demonstrate the potential for improved diagnosis and monitoring of disease progress of intraocular lesions using ultrahigh-field magnetic resonance microscopy (MRM) at 7.1 Tesla.

METHODS

High-resolution ex vivo ocular magnetic resonance (MR) images were acquired on an ultrahigh-field MR system (7.1 Tesla, ClinScan, Bruker BioScan, Germany) using a 2-channel coil with 4 coil elements and T2-weighted turbo spin echo (TSE) sequences of human eyes enucleated because of different intraocular lesions. Imaging parameters were: 40×40 mm field of view, 512×512 matrix, and 700 µm slice thickness. The results were correlated with in vivo ultrasound and histology of the enucleated eyes.

RESULTS

Imaging was performed in enucleated eyes with choroidal melanoma, malignant melanoma of iris and ciliary body with scleral perforation, ciliary body melanoma, intraocular metastasis of esophageal cancer, subretinal bleeding in the presence of perforated corneal ulcer, hemorrhagic choroidal detachment, and premature retinopathy with phthisis and ossification of bulbar structures. MR imaging allowed differentiation between solid and cystic tumor components. In case of hemorrhage, fluid-fluid levels were identified. Melanin and calcifications caused significant hypointensity. Microstructural features of eye lesions identified by MRM were confirmed by histology.

CONCLUSION

This study demonstrates the potential of MRM for the visualization and differential diagnosis of intraocular lesions. At present, the narrow bore of the magnet still limits the use of this technology in humans in vivo. Further advances in ultrahigh-field MR imaging will permit visualization of tumor extent and evaluation of nonclassified intraocular structures in the near future.

Development of a rat model for investigation of experimental splinted uretero-ureterostomy, ureteral stenting and stenosis

BACKGROUND AND AIM

The objective of this study was to establish a rat model to develop hypertrophic fibrosis for subsequent safe application of ureteral stents in order to investigate new treatment options for ureteral strictures.

MATERIALS AND METHODS

Thirty-two male Sprague-Dawley rats were used. Group 1: Sham surgery; group 2: surgery with uretero-ureteral anastomosis and stenting. Histopathological evaluation was carried out using 5-bromo-2-deoxyuridine administration before the animals were sacrificed.

RESULTS

A total of thirty-one animals reached the final end-point. The most common surgical complications were urine extravasation and stent dislocations. Histological examination showed full regeneration of urothelium after 28 days and development of a scarring process. With stent insertion, moderate hypertrophia was seen. In contrast, the sham group had no evidence of significant scarring or stricture formations.

CONCLUSION

Our rat model allows for investigation of the wound healing processes of urothelium of the ureteral wall and the study of the application of new miniature stents as drainage and drug carriers.

[Diagnosis of conjunctival neoplastic lesions by confocal in-vivo microscopy]

BACKGROUND

There is a wide spectrum of benign and malignant conjunctival neoplastic lesions that are often impossible to distinguish clinically by slit-lamp microscopy. The current study was undertaken to compare in-vivo confocal laser scanning microscopy (CLSM) and histology for the preoperative assessment of benign or malignant status.

CASE REPORTS

We present the clinical details of three patients. In two cases the neoplastic lesions were classified as benign (actinic keratosis). In-vivo CLSM revealed densely layered, sometimes hyperreflective conjunctival epithelial cells, together with multiple inflammatory cells and microcysts. Correlated findings on histology showed keratinisation with inflammatory infiltrates and intracellular oedema formation. In-vivo CLSM images in the third patient revealed interruptions of the layered epithelial structure with regular conjunctival epithelium co-existing with complexes of enlarged cells with polymorphic nuclei. Histology also showed an abrupt transition from regular squamous epithelium to hyperplastic, dysplastic squamous epithelium. In this case the neoplastic lesion was classified as carcinoma in situ.

DISCUSSION

The in-vivo CLSM images correlated positively with histology findings. Although in-vivo CLSM offers the capability to perform non-invasive examinations over time, associated histological assessment (because of its more precise detail and additional staining techniques) remains indispensable for planning further action and determining the prognosis.

[Primary cerebellar T-cell lymphoma]

Primary central nervous system T-cell lymphomas are rare and have to be differentiated from reactive lesions. It is therefore essential to use all possible tools to establish the diagnosis, including immunohistochemistry, molecular genetic analysis, and/or cytogenetic methods. In this paper we present the case of a primary cerebellar T-cell lymphoma in a 50-year-old man; a clonal T-cell receptor gene rearrangement was documented. After two cycles of methotrexate therapy the patient developed Pneumocystis carinii-induced pneumonia, dying 10 weeks after his diagnosis. The autopsy did not reveal any residual tumour.

Upper limb amelia, facial clefts, holoprosencephaly, and interrupted aortic arch

The combination of bilateral brachial amelia, facial clefting, and holoprosencephaly is rare. To our knowledge, only 4 patients with this combination of malformations have been described so far. We report on a male fetus with bilateral brachial amelia, complex facial clefts, frontal craniosynostosis and hypoplasia, thoracic kyphoscoliosis, and holoprosencephaly. In addition, an interrupted aortic arch, a muscular ventricular septal defect, and localized noncompaction of the septal myocardium were present. Although fibroblast culture was not successful, fluorescent in situ hybridization of paraffin-embedded tissue showed a normal set of chromosomes 13, 18, 21, X and Y. Our observation supports the hypothesis that this malformation combination may constitute a distinct entity. However, so far, a genetic defect remains to be identified.

Construction and validation of a bone marrow tissue microarray

BACKGROUND

The use of tissue microarrays (TMAs) is now a generally accepted method for the investigation of solid tumours. However, little is known about the applicability of the TMA technique for analysis of patients with acute leukaemia. A bone marrow (BM)-TMA analysis with 15 different immunohistochemical markers was performed. The TMA was validated by comparison with the corresponding full tissue sections.

MATERIALS AND METHODS

A BM-TMA comprising 148 cases of acute leukaemia, including 115 acute myeloid leukaemia (AML) and 33 acute lymphoblastic leukaemia (ALL) cases, was constructed. Expression of CD3, CD10, CD15, CD20, CD34, CD61, CD68, CD79a, CD99, CD117, CD138, myeloperoxidase, haemoglobin A1, glycophorin and terminal deoxynucleotidyl transferase was immunohistochemically analysed. 50 cases of the TMA were directly compared with the corresponding full tissue section to validate the results.

RESULTS

Morphologically and immunohistochemically, 6 (4%) of 148 cases and 765 (11%) cores of 6912 individual analyses were not evaluable. A direct comparison of TMA cases with conventional full sections showed a concordance of the results of 100%.

CONCLUSIONS

The small size of bone-marrow biopsies and the presence of bony trabeculae do not preclude construction and analysis of acute leukaemia TMAs. Acute leukaemia cases on TMA displayed the characteristic phenotypic profiles expected in different AML and ALL subtypes. Therefore, the TMA technique is also a promising method for high-throughput analysis of combined marker expression and clinicopathological correlations in patients with leukaemia.

Tissue microarray technology: principles, pitfalls and perspectives--lessons learned from hematological malignancies

Detection, validation and incorporation into clinical use of new diagnostic, prognostic and therapeutic molecular targets in modern medical science should be time- and cost-efficient. Here, we discuss the principles, advantages, disadvantages and possible pitfalls of tissue microarray (TMA) technology, a powerful tool for high throughput large-scale morphological in situ analysis of molecular targets. Based on recent observations from molecular profiling of hematological malignancies, we review potential TMA applications assessing molecular targets in large collectives of tissue specimens.

Die diagnostische und prädiktive Bedeutung von Kit (CD117)

CD117 (Kit) ist eine transmembrane Tyrosinkinase. Es ist ein klassischer Wachstumsfaktorrezeptor und bindet spezifisch den sogenannten Stammzellfaktor (auch Kit-Ligand oder Mastzellwachstumsfaktor genannt). Kit wird physiologischerweise in hämatopoetischen Stammzellen, Keimzellen der Gonaden, den interstitiellen Zellen von Cajal (intestinale Schrittmacherzellen) und Mastzellen sowie Melanozyten exprimiert. Die Kit-mediierte Signaltransduktion reguliert Proliferation, Differenzierung und Apoptose und spielt eine Rolle bei der Gametogenese, Hämatopoiese, Mastzellentwicklung, Melanogenese und Entwicklung der Cajalzellen. Von herausragender diagnostischer Bedeutung ist der Nachweis einer CD117-Expression bei den gastrointestinalen Stromatumoren (GIST). Ungefähr 95% aller GIST sind immunhistochemisch CD117-positiv. Die überwiegende Mehrzahl aller anderen Sarkome sowie Karzinome und auch Lymphome sind CD117-negativ, sodass dieser Marker eine sehr gute Sensitivität und Spezifität für die Diagnose eines GIST aufweist. Darüber hinaus sind aktivierende Mutationen im Kit-Onkogen von entscheidender pathogenetischer Bedeutung der GIST. 80–85% aller GIST weisen derartige Mutationen auf. Da mit dem Medikament Imatinib (Glivec®) ein spezifischer Tyrosinkinase-Hemmer zur Verfügung steht, ist der Nachweis beziehungsweise die Lokalisation einer spezifischen Mutation auch der wichtigste prädiktive Faktor. Neben GIST sind systemische Mastozytosen sowie Seminome am häufigsten CD117-positiv. Diese Neoplasien weisen allerdings Mutationen in anderen Exons des Kit-Gens als GIST auf und sind nur teilweise Imatinib-sensitiv. Die CD117-Expression ist aber nicht spezifisch für diese Entitäten. Andere maligne Tumore, vor allem adenoid-zystische Karzinome, Tymuskarzinome und Melanome können das Protein ebenfalls exprimieren. Ganz selten gilt dies auch noch für andere Entitäten. Bei der überwiegenden Mehrzahl der Fälle liegt aber eine Wild-Typ Kit-Gen-Konfiguration vor und damit fehlt die molekulare Basis für eine erfolgreiche Imatinib-Therapie. Der reine immunhistochemische Nachweis einer CD117-Expression stellt also – mit Ausnahme des GIST – keine verlässliche therapeutische Grundlage dar. Der molekular-pathologische Nachweis der CD117-Expression und des Mutationsstatus bei GIST (und anderen Tumoren) bringt geradezu paradigmatisch die Bedeutung moderner molekularer Diagnostik im Zeitalter der zielgerichteten, individualisierten Therapie zum Ausdruck.

Expression of minichromosome maintenance protein 2 as a marker for proliferation and prognosis in diffuse large B-cell lymphoma: a tissue microarray and clinico-pathological analysis

Background

Minichromosome maintenance (MCM) proteins are essential for the initiation of DNA replication and have been found to be relevant markers for prognosis in a variety of tumours. The aim of this study was to assess the proliferative activity of diffuse large B-cell lymphoma (DLBCL) in tissue microarray (TMA) using one of the minichromosome maintenance proteins (Mcm2) and to explore its potential value to predict prognosis.

Methods

Immunohistochemistry for Mcm2 was performed on TMAs constructed from 302 cases of DLBCL. A monoclonal mouse antibody was used after heat induced antigen retrieval. Mcm2 expression was scored quantitatively. Positivity for Mcm2 was defined as presence of nuclear expression of Mcm2 in greater than or equal to 40 % of tumour cells. A statistical analysis was carried out of the association of Mcm2 and the clinico-pathological characteristics.

Results

Mcm2 expression was clearly evident in the nuclei of proliferating non-neoplastic cells and tumour cells. Positivity for Mcm2 was found in 46% (98/211) of analysable cases. A significant correlation existed between Mcm2 expression and presence of bulky disease (p = 0.003). Poor disease specific survival was observed in patients with DLBCL positive for Mcm2 expression in the univariate analysis (p = 0.0424).

Conclusion

Mcm2 expression can be used to assess tumour proliferation and may be useful as an additional prognostic marker to refine the prediction of outcome in DLBCL.

Marginal zone lymphoma of the lacrimal gland spreading to the lung and the bone marrow 11 years after first symptoms

We report on the case of a 52-year-old male presenting with an extranodal marginal zone lymphoma of the mucosa-associated tissue (MALT lymphoma) in the lung 11 years after radiotherapy for a MALT lymphoma of the lacrimal gland, which was primarily diagnosed as dacryoadenitis. Both tumors were investigated by immunohistochemistry and molecular techniques demonstrating their clonal genetic relationship. Both harbored the t(14;18)(q32;q21) and a trisomy 3 and showed identical immunoglobulin heavy-chain gene rearrangements. At the time of pulmonary relapse, clonal CD20- and CD43-positive bone marrow B lymphocytes were detected as well. The elaboration of this case emphasizes the importance of the combined use of modern diagnostic methods for establishment of correct diagnosis of MALT lymphomas at late relapses, which is essential for proper patient management.

Rare expression of T-cell markers in classical Hodgkin's lymphoma

Hodgkin's and Reed-Sternberg cells of classical Hodgkin's lymphoma are primarily of B-cell origin, although there are instances of T-cell antigen expression suggesting T-cell origin. We comprehensively analyzed expression of various T-cell antigens in 259 classical Hodgkin's lymphoma cases using the tissue microarray technique. Expression of the T-cell antigens CD2, CD3, CD4, CD5, CD7 and CD8 was assessed by immunohistochemistry. Hodgkin's and Reed-Sternberg cells of T-cell marker-positive cases were microdissected and analyzed by a multiplex polymerase chain reaction for clonal immunoglobulin heavy chain- and T-cell receptor gamma gene rearrangements. In all, 12 cases (5%) expressed at least one T-cell marker in the following order: CD2 in 11 cases, CD4 in five, CD3 in two, and CD5 and CD8 in one case each; there were no CD7-positive cases, and five cases (2%) expressed more than one T-cell antigen. In positive cases, a mean fraction of 40% of the Hodgkin's and Reed-Sternberg cells (range 20-100%) expressed the analyzed T-cell markers. Two cases (<1%) evidenced clonal T-cell receptor gamma gene rearrangement. Phenotypic expression of T-cell antigens in Hodgkin's and Reed-Sternberg cells of classical Hodgkin's lymphoma is rare (5%), while genotypically, less than 1% of classical Hodgkin's lymphomas are of possible T-cell origin. Therefore, T-cell antigen expression on Hodgkin's and Reed-Sternberg cells is aberrant in the majority of cases and only infrequently classical Hodgkin's lymphomas are of T-cell origin.

Lack of clinical efficacy of imatinib in metastatic melanoma

This two-centre phase-II trial aimed at investigating the efficacy of imatinib in metastasised melanoma patients in correlation to the tumour expression profile of the imatinib targets c-kit and platelet-derived growth factor receptor (PDGF-R). The primary study end point was objective response according to RECIST, secondary end points were safety, overall and progression-free survival. In all, 18 patients with treatment-refractory advanced melanoma received imatinib 800 mg day(-1). In 16 evaluable patients no objective responses could be observed. The median overall survival was 3.9 months, the median time to progression was 1.9 months. Tumour biopsy specimens were obtained from 12 patients prior to imatinib therapy and analysed for c-kit, PDGF-Ralpha and -Rbeta expression by immunohistochemistry. In four cases, cell lines established from these tumour specimens were tested for the antiproliferative effects of imatinib and for functional mutations of genes encoding the imatinib target molecules. The tumour specimens stained positive for CD117/c-kit in nine out of 12 cases (75%), for PDGF-Ralpha in seven out of 12 cases (58%) and for PDGF-Rbeta in eight out of 12 cases (67%). The melanoma cell lines showed a heterogenous expression of the imatinib target molecules without functional mutations in the corresponding amino-acid sequences. In vitro imatinib treatment of the cell lines showed no antiproliferative effect. In conclusion, this study did not reveal an efficacy of imatinib in advanced metastatic melanoma, regardless of the expression pattern of the imatinib target molecules c-kit and PDGF-R.

High Specificity of Combined TRAP and DBA.44 Expression for Hairy Cell Leukemia

Because of marrow fibrosis, bone marrow aspirations are often nonconclusive in patients with hairy cell leukemia (HCL). Therefore, histologic examination is important in HCL but often difficult in cases with low numbers of tumor cells. A combined immunohistochemical positivity for DBA.44 and tartrate-resistant phosphatase was previously found in 100% of HCL and suggested to be specific for this diagnosis. To further assess the diagnostic specificity and sensitivity of this immunohistochemical approach in a higher number of cases, we analyzed 56 HCLs and lymphoma tissue microarrays, including 840 cases of the most frequent non-Hodgkin lymphomas. All HCLs showed combined positivity for these two proteins (100% sensitivity). Both antibodies were often positive in other lymphoma types. DBA.44 reactivity was especially frequent in follicular lymphomas (46%), whereas tartrate-resistant acid phosphatase (TRAP) expression was often seen in mantle cell lymphomas (57%), primary mediastinal large B-cell lymphomas (54%), and chronic lymphocytic leukemia/small lymphocytic lymphoma (41%). A combined DBA.44/TRAP positivity was seen in only 3% of non-HCL non-Hodgkin lymphomas, including cases of diffuse large B-cell lymphomas, follicular lymphomas, chronic lymphatic leukemia/small lymphocytic leukemias, and mantle cell lymphomas. Overall, these data confirm the utility of combined immunohistochemical DBA.44/TRAP expression analysis in confirming the diagnosis of HCL. However, combined positivity for these markers is highly sensitive but not absolutely specific for HCL.

Aberrant expression of cell cycle regulators in Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma

The characteristic Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma, although highly positive for proliferation markers, do not accumulate to excessive cell numbers. These cells are characterized by abortive mitotic cycles, leading to multinucleation or cell death in mitosis. We have previously described high expression of G1-phase cyclins in classical Hodgkin's lymphoma, which could explain the high percentage of cells staining for proliferation markers. To further our understanding of proliferation control in classical Hodgkin's lymphoma, we extended our immunohistochemical analysis to the main S-phase cyclin, cyclin A, and its regulators p21CIP1 and p27KIP1. Expression of proliferating cell nuclear antigen (PCNA) was used as an additional marker for cells being in either S- or G2-phase. In 47% (112/239) of classical Hodgkin's lymphoma cases p21CIP1 was detected within a mean frequency of 15% positive Hodgkin's and Reed-Sternberg cells per case. Similarly, 47% (116/249) of the cases stained positively for p27KIP1 with a mean frequency of expression in Hodgkin's and Reed-Sternberg cells of 12%. In contrast, 90% of the cells in all 246 evaluable classical Hodgkin's lymphoma cases were positive for PCNA. In addition, 98% of Hodgkin's and Reed-Sternberg cells in 99% (250/253) of the cases stained strongly positive for cyclin A. These findings further corroborate the hypothesis that Hodgkin and Reed-Sternberg cells exhibit a disturbed cell cycle with an abnormally short or even absent G1-phase. In contrast to other tumors, expression of PCNA or cyclin A had no prognostic value for patient survival.

Rare expression of KIT (CD117) in lymphomas: a tissue microarray study of 1166 cases

AIMS

Imatinib mesylate specifically inhibits KIT tyrosine kinase activity, and has been proven to be effective in the treatment of gastrointestinal stromal tumours. Because other KIT-expressing malignancies might benefit from Imatinib therapy, we evaluated the distribution and expression of KIT in 1166 cases of malignant lymphoma.

MATERIALS AND RESULTS

Tissue microarrays (TMAs) containing 824 non-Hodgkin's lymphoma (NHL) and 342 Hodgkin's lymphoma (HL) cases were immunohistochemically analysed for the expression of the KIT protein. Two KIT-positive NHLs were sequenced using polymerase chain reaction analysis. One T-cell lymphoma and one follicular lymphoma of the 747 NHL cases (0.3%) were positive for KIT. All HLs were Kit-negative. None of the KIT-positive cases showed a kit gene mutation.

CONCLUSIONS

KIT expression is a very rare event in NHL and virtually absent in HL. In the few positive cases, the aberrant expression is not caused by a mutation in the 'hot-spots' of the kit gene, indicating that treatment of these tumours with Imatinib may be ineffective.

Ciprofloxacin-induced acute liver injury: case report and review of literature

Ciprofloxacin is a fluorinated quinolone antibiotic with relatively low occurrence of adverse side effects. However, increasing evidence suggests that ciprofloxacin may cause severe liver damage. Until now, 14 cases of ciprofloxacin-associated liver injuries have been reported. We describe a case of a 22-year-old male who developed hepatic failure after intake of ciprofloxacin. The patient had been treated with 2 x 250 mg ciprofloxacin per day. He presented with symptoms of acute liver failure 14 days later. Liver biopsy revealed extensive hepatocellular necrosis involving zones 3 and 2 of hepatic acini and a mixed inflammatory infiltration containing abundant eosinophils. Symptoms resolved after corticoidsteroid therapy. In the present paper, we report the clinico-pathological characteristics of a case of ciprofloxacin-associated acute hepatic failure and discuss the current literature.