Expanding the clinicopathological spectrum of TGFBR3-PLAG1 rearranged salivary gland neoplasms with myoepithelial differentiation including evidence of high-grade transformation.

PLAG1 rearrangements have been described as a molecular hallmark of salivary gland pleomorphic adenoma (PA), carcinoma ex pleomorphic adenoma (CEPA), and myoepithelial carcinoma (MECA). Several fusion partners have been described, however, commonly no further assignment to the aforementioned entities or a morphological prediction can be made based on the knowledge of the fusion partner alone. In contrast, TGFBR3-PLAG1 fusion has been specifically described and characterized as an oncogenic driver in MECA, and less common in MECA ex PA. Here, we describe the clinicopathological features of three TGFBR3-PLAG1 fusion-positive salivary gland neoplasms, all of which arose in the deep lobe of the parotid gland. Histopathology showed high morphological similarities, encompassing encapsulation, a polylobular growth pattern, bland basaloid and oncocytoid cells with myoepithelial differentiation, and a distinct sclerotic background. All cases showed at least limited, unusual foci of minimal invasion into adjacent salivary gland tissue, including one case with ERBB2 (Her2/neu) amplified, TP53 mutated high-grade transformation, and lymph node metastases. Of note, all cases illustrated focal ductal differentiation. Classification remains difficult, as morphological overlaps between myoepithelial-rich cellular PA, myoepithelioma, and MECA were observed. However, evidence of minimal invasion advocates classification as low-grade MECA. This case series further characterizes the spectrum of uncommon cellular myoepithelial neoplasms harboring TGFBR3-PLAG1 fusion, which show recurrent minimal invasion of the adjacent salivary gland tissue, a predilection to the deep lobe of the parotid gland, and potential high-grade transformation.

Methylation and copy number profiling: emerging tools to differentiate osteoblastoma from malignant mimics?

Rearrangements of the transcription factors FOS and FOSB have recently been identified as the genetic driver event underlying osteoid osteoma and osteoblastoma. Nuclear overexpression of FOS and FOSB have since then emerged as a reliable surrogate marker despite limitations in specificity and sensitivity. Indeed, osteosarcoma can infrequently show nuclear FOS expression and a small fraction of osteoblastomas seem to arise independent of FOS/FOSB rearrangements. Acid decalcification and tissue preservation are additional factors that can negatively influence immunohistochemical testing and make diagnostic decision-making challenging in individual cases. Particularly aggressive appearing osteoblastomas, also referred to as epithelioid osteoblastomas, and osteoblastoma-like osteosarcoma can be difficult to distinguish, underlining the need for additional markers to support the diagnosis. Methylation and copy number profiling, a technique well established for the classification of brain tumors, might fill this gap. Here, we set out to comprehensively characterize a series of 77 osteoblastomas by immunohistochemistry, fluorescence in-situ hybridization as well as copy number and methylation profiling and compared our findings to histologic mimics. Our results show that osteoblastomas are uniformly characterized by flat copy number profiles that can add certainty in reaching the correct diagnosis. The methylation cluster formed by osteoblastomas, however, so far lacks specificity and can be misleading in individual cases.

Autopsy-Based Pulmonary and Vascular Pathology: Pulmonary Endotheliitis and Multi-Organ Involvement in COVID-19 Associated Deaths.

BACKGROUND: Findings from autopsies have provided evidence on systemic microvascular damage as one of the underlying mechanisms of Coronavirus disease 2019 (CO-VID-19). The aim of this study was to correlate autopsy-based cause of death in SARS-CoV-2, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive patients with chest imaging and severity grade of pulmonary and systemic morphological vascular pathology. METHODS: Fifteen SARS-CoV-2 positive autopsies with clinically distinct presentations (age 22-89 years) were retrospectively analyzed with focus on vascular, thromboembolic, and ischemic changes in pulmonary and in extrapulmonary sites. Eight patients died due to COVID-19 associated respiratory failure with diffuse alveolar damage in various stages and/or multi-organ failure, whereas other reasons such as cardiac decompensation, complication of malignant tumors, or septic shock were the cause of death in 7 further patients. The severity of gross and histopathological changes was semi-quantitatively scored as 0 (absent), 1 (mild), and 3 (severe). Severity scores between the 2 groups were correlated with selected clinical parameters, initial chest imaging, autopsy-based cause of death, and compared using Pearson χ2 and Mann-Whitney U tests. RESULTS: Severe pulmonary endotheliitis (p = 0.031, p = 0.029) and multi-organ involvement (p = 0.026, p = 0.006) correlated significantly with COVID-19 associated death. Pulmonary microthrombi showed limited statistical correlation, while tissue necrosis, gross pulmonary embolism, and bacterial superinfection did not differentiate the 2 study groups. Chest imaging at hospital admission did not differ either. CONCLUSIONS: Extensive pulmonary endotheliitis and multi-organ involvement are characteristic autopsy features in fatal CO-VID-19 associated deaths. Thromboembolic and ischemic events and bacterial superinfections occur frequently in SARS-CoV-2 infection independently of outcome.

Activating mutations in the MAP-kinase pathway define non-ossifying fibroma of bone.

Non-ossifying fibroma (NOF), which occasionally results in pathologic fracture, is considered the most common benign and self-limiting lesion of the growing skeleton. By DNA sequencing we have identified hotspot KRAS, FGFR1 and NF1 mutations in 48 of 59 patients (81.4%) with NOF, at allele frequencies ranging from 0.04 to 0.61. Our findings define NOF as a genetically driven neoplasm caused in most cases by activated MAP-kinase signalling. Interestingly, this driving force either diminishes over time or at least is not sufficient to prevent autonomous regression and resolution. Beyond its contribution to a better understanding of the molecular pathogenesis of NOF, this study adds another benign lesion to the spectrum of KRAS- and MAP-kinase signalling-driven tumours. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

[Molecular pathology in the diagnosis of bone tumors: current concepts]. / Molekulare Pathologie in der Diagnostik der Knochentumoren: Aktueller Stand.

The integrative evaluation of histology and corresponding imaging is essential for the classification of bone tumors. Until a few years ago, there were hardly any molecular markers that could be used for diagnostic purposes. However, exome- and genome-wide sequencing analyses have since uncovered a number of tumor-specific aberrations that can be very helpful in ambiguous cases. In addition to characteristic gene mutations (e.g. H3F3A and H3F3B in giant-cell tumors and chondroblastomas), the detection of fusion transcripts (e.g. structural rearrangements in the AP­1 transcription factors FOS and FOSB in osteoid osteomas and osteoblastomas) plays an increasing role. The article gives an overview of the current state of knowledge of the most important alterations in bone tumors.

Triple-induction treatment for locally advanced non-small cell lung cancer: a case report of pathological complete response.

BACKGROUND: In patients with resectable stage III non-small cell lung cancer (NSCLC), induction chemoimmunotherapy followed by surgical resection has shown unprecedented rates of pathological response and event-free survival. However, a triple-induction including radiochemotherapy and immunotherapy followed by surgical resection has not been routinely established in clinical practice. CASE PRESENTATION: We report the case of a 47-year-old patient with stage IIIA NSCLC who was treated in a combined concept including induction concurrent radiochemotherapy, followed by 4 cycles of pembrolizumab and subsequent intrapericardial left-sided pneumonectomy. Histological analysis revealed a pathological complete response. CONCLUSIONS: The case demonstrates that the combination of neoadjuvant chemo-, radio- and immunotherapy in advanced NSCLC may lead to a relevant down-staging and may enable a R0-resection of a borderline resectable tumor. However, the combination of four different treatment modalities requires resilience and a good performance status. A triple induction treatment may be a promising option for selected patients with locally advanced NSCLC and good performance status.

Challenging Tumor Heterogeneity with HER2, p16 and Somatostatin Receptor 2 Expression in a Case of EBV-Associated Lymphoepithelial Carcinoma of the Salivary Gland.

BACKGROUND: Lymphoepithelial carcinoma of the salivary glands (LECSG) is a rare disease in the Western hemisphere that is typically associated with an EBV infection. The molecular mechanisms of LECSG tumorigenesis are poorly understood. RESULTS: Here we report a case of EBV-associated LECSG with an unusual immunophenotype. The tumor exhibited bi-morphic histological features with a mutually exclusive expression of HER2 and p16. The p16-positive domain of the tumor immunohistochemically co-expressed late membrane protein 1 (LMP-1), while the HER2 positive domain did not. Both tumor regions expressed SSTR2. METHODS: In situ hybridization confirmed the EBV origin of the tumor while extensive immunohistochemical characterization and the recently established RNA-based next generation sequencing panel ("SalvGlandDx" panel) did not reveal evidence for another salivary gland neoplasm. No HPV co-infection was detected by in situ hybridization or PCR-based screenings and no ERBB2 gene amplification was detected by fluorescence in situ hybridization. CONCLUSION: These findings suggest tumor heterogeneity and lack of genomic aberrations in EBV-associated LECSGs. The heterogenous and unusual immunohistochemical features explain the diagnostic difficulties and simultaneously extend the immunophenotype spectrum of this tumor entity.

Pseudogout growing from the temporomandibular joint into the middle cranial fossa.

Calcium pyrophosphate dihydrate deposition disease (CPDD or pseudogout) is a degenerative joint disease. It is defined by the presence of calcium pyrophosphate dihydrate crystals. It usually manifests in the knee and wrist. Manifestation in the temporomandibular joint (TMJ) is only reported in case reports. We present a patient with CPDD mimicking a malignant tumor of the TMJ. A 53-year-old woman presented with progressive pain and a slow-growing swelling of the left TMJ. Imaging showed an extensive mass in the infratemporal fossa extending into the middle cranial fossa and compressing the temporal lobe. Assuming a potential malignancy, we excised the growth, which extended into the dura. We covered the resulting tissue defect within the primary surgery using a microsurgically anastomosed scapular flap and performed further reconstructive surgeries. Calcium pyrophosphate dihydrate crystals were found in the histopathologic examination of the excised tissue, resulting in the diagnosis of CPDD. That is a benign diagnosis, but we treated it like a malignancy. This leads us to the question, was there overtreatment? Tumoral CPDD in the TMJ can be a difficult diagnosis to obtain. The treatment remains controversial, but complete excision of the mass was performed in most reported cases.

Endobronchial Ultrasound-Guided Transbronchial Forceps Biopsy: A Retrospective Bicentric Study Using the Olympus 1.5 mm Mini-Forceps.

When evaluating mediastinal/hilar lymphadenopathy (LAD) or masses, guidelines recommend endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA) as an initial technique for tissue analysis and diagnosis. However, owing to the small sample size obtained by needle aspiration, its diagnostic yield (DY) is limited. EBUS transbronchial forceps biopsy (TBFB) used as a complimentary technique to EBUS-TBNA might allow for better histopathological evaluation, thus improving DY. In this retrospective bicentric study, we assessed the DY and safety of an EBUS-guided 1.5 mm mini-forceps biopsy combined with EBUS-TBNA for the diagnosis of mediastinal/hilar LAD or masses compared to EBUS-TBNA alone. In total, 105 patients were enrolled. The overall DY was 61.9% and 85.7% for TBNA alone and EBUS-TBNA combined with EBUS-TBFB, respectively (p < 0.001). While the combined approach was associated with a significantly higher DY for lung cancer diagnosis (97.1% vs. 76.5%, p = 0.016) and sarcoidosis (85.2% vs. 44.4%, p = 0.001), no significant differences in DY were calculated for subgroups with smaller sample sizes such as lymphoma. No major adverse events were observed. Using a 1.5 mm mini-forceps is a safe and feasible technique for biopsy of mediastinal or hilar LAD or masses with superior overall DY compared to EBUS-TBNA as a standalone technique.

Targeting ALK in Neuroendocrine Tumors of the Lung.

Background: Anaplastic lymphoma kinase (ALK) rearrangements are known oncogenic drivers in non-small cell lung cancer (NSCLC). Few case reports described the occurrence of such rearrangements in large cell neuroendocrine carcinomas (LCNECs) of the lung without information on clinical responses to ALK tyrosine kinase inhibitors (TKIs) in these cases. Currently, neuroendocrine tumors of the lungs are not screened for ALK rearrangements. Methods: To illustrate the clinical impact of molecular characterization in LCNECs, we report the disease course in three patients with ALK-rearranged metastatic LCNEC from our clinical routine, as well as their treatment response to ALK TKIs (index cases). To gain insight into the prevalence of ALK rearrangements in neuroendocrine tumors of the lung, we analyzed a retrospective cohort of 436 tumor biopsies including LCNEC (n = 61), small cell lung cancer (SCLC) (n = 206), typical (n = 91) and atypical (n = 69) carcinoids, and mixed histology (n = 9) for the presence of ALK rearrangements using a sequential diagnostic algorithm. ALK immunohistochemistry (IHC) was evaluable in 362 cases; fluorescence in situ hybridization (FISH) was evaluable in 28 out of the 35 IHC-positive cases, followed by next-generation sequencing (NGS) that was available in 12 cases. Results: Within the retrospective cohort, ALK IHC was positive in 35 out of 362 (9.7%) evaluable samples. FISH was positive in 3 out of the 28 (10.7%) evaluable cases: 2 with atypical carcinoids and 1 with LCNEC. Additionally, the 3 index cases showed positive ALK IHC, which was confirmed by NGS. Within the retrospective cohort, NGS confirmed the presence of an ALK genomic rearrangement in one FISH-positive atypical carcinoid where material was sufficient for sequencing. Two out of three patients with metastatic ALK-rearranged LCNEC received up-front treatment with the ALK TKI alectinib and showed rapid tumor response at all metastatic sites, including multiple brain metastases. Conclusions: ALK rearrangements represent rare but targetable oncogenic driver alterations in LCNEC. Contrarily to NSCLC, the detection of ALK rearrangements in neuroendocrine tumors of the lung is challenging, since ALK IHC can lead to false-positive results and therefore needs confirmation by FISH or NGS. Up-front comprehensive molecular profiling with NGS should be performed in metastatic LCNEC in order not to miss actionable genomic alterations.

SalvGlandDx - a comprehensive salivary gland neoplasm specific next generation sequencing panel to facilitate diagnosis and identify therapeutic targets.

Diagnosis of salivary gland neoplasms is often challenging due to their high morphological diversity and overlaps. Several recurrent molecular alterations have been described recently, which can serve as powerful diagnostic tools and potential therapeutic targets (e.g. NTRK or RET fusions). However, current sequential molecular testing can be expensive and time consuming. In order to facilitate the diagnosis of salivary gland neoplasms, we designed an all-in-one RNA-based next generation sequencing panel suitable for the detection of mutations, fusions and gene expression levels (including NR4A3) of 27 genes involved in salivary gland neoplasms. Here we present the validation of the "SalvGlandDx" panel on FFPE histological specimen including fine needle aspiration (FNA) cell block material, against the standard methods currently used at our institution. In a second part we describe selected unique cases in which the SalvGlandDx panel allowed proper diagnosis and new insights into special molecular characteristics of selected salivary gland tumors. We characterize a unique salivary gland adenocarcinoma harboring a ZCCHC7-NTRK2 fusion, a highly uncommon spindle cell and pseudoangiomatoid adenoid-cystic carcinoma with MYBL1-NFIB fusion, and a purely oncocytic mucoepidermoid carcinoma, whereas diagnosis could be made by detection of a CRTC3-MAML2 rearrangement on the cell block specimen of the FNA. Further, a rare case of a SS18-ZBTB7A rearranged low-grade adenocarcinoma previously described as potential spectrum of microsecretory adenocarcinoma, is reported. In addition, features of six cases within the spectrum of polymorphous adenocarcinoma / cribriform adenocarcinoma of salivary gland including PRKD1 p.E710D mutations and novel fusions involving PRKAR2A-PRKD1, SNX9-PRKD1 and ATL2-PRKD3, are described.

A Rare Finding in Dupuytren's Disease - Heterotopic Ossification.

We present the case of a severe and long-standing Dupuytren's contracture where intraoperatively an ossified nodule was encountered within the diseased tissue. Histologically palmar fibromatosis in contact with cartilaginous tissue with central ossification could be confirmed, compatible with metaplasia. Our finding suggests that metaplastic activity inherent to longstanding, severely diseased Dupuytren's tissue can lead to heterotopic ossification.

Combined histomorphologic and immunohistochemical phenotype to predict the presence of vascular invasion in colon cancer.

PURPOSE: Vascular invasion is an adverse prognostic factor in colorectal cancer and often is considered an indication for systemic adjuvant therapy. The aim of this study was to develop a predictive model of vascular invasion in a large cohort of colon cancers with use of tumor-related features and immunohistochemical analysis of protein markers. METHODS: A tissue microarray including 427 colon cancers was evaluated for 14 immunohistochemical protein markers. Complete data on pT, pN, tumor grade, tumor border configuration, vascular invasion, and tumor diameter were available. Classification and regression tree analysis was performed. RESULTS: The presence of vascular invasion independently predicted adverse outcome (P < 0.001; hazard ratio = 1.52 (1.3 to 1.8)) and decreased survival from 49.0 to 19.0 months (P < 0.001) even in lymph node-positive patients. Tumor border configuration, Ki67, urokinase plasminogen activator receptor, and Raf-1 kinase inhibitor protein expression were predictive of vascular invasion. The cross-validated misclassification rate was 23.7 percent indicating a significant predictive accuracy of this model. CONCLUSIONS: Tumor border configuration, Ki67, urokinase plasminogen activator receptor, and Raf-1 kinase inhibitor protein immunohistochemistry are highly predictive of vascular invasion and may play a decisive role in individualizing adjuvant treatment.

Delineation of distinct tumour profiles in mantle cell lymphoma by detailed cytogenetic, interphase genetic and morphological analysis.

Mantle cell lymphoma (MCL) is an aggressive lymphoid tumour characterized by the translocation t(11;14)(q13;q32) and a poor clinical outcome (median survival: 3-4 years). Recent studies revealed that increased proliferation of the tumour cells and certain chromosomal aberrations, such as deletions of 17p13 and 9p21 represent major adverse biological markers in this disease, although the molecular targets of chromosomal imbalances in MCL have not been identified for the large majority of loci affected. To correlate histomorphological and proliferation features of MCL with genetic findings, we investigated 223 MCL by fluorescence in situ hybridization (FISH) (n = 157) and/or classical cytogenetic banding analysis (n = 129). FISH analysis turned out to be distinctly more sensitive in the delineation of aberrations. Complex karyotypic alterations were associated with higher proliferation indices and inferior prognosis. A comprehensive analysis of biological features including genetic alterations in MCL by hierarchical clustering resulted in the delineation of four tumour subgroups differing with respect to their genetic constitution and suggesting different transformation or progression pathways. Moreover, in one of the groups identified, a more indolent clinical behaviour was associated with few secondary aberrations and fewer known high-risk chromosomal aberrations, which points to the importance of the quality of karyotypic evolution in MCL tumours.

Lack of methylthioadenosine phosphorylase expression in mantle cell lymphoma is associated with shorter survival: implications for a potential targeted therapy.

PURPOSE: To determine the methylthioadenosine phosphorylase (MTAP) gene alterations in mantle cell lymphoma (MCL) and to investigate whether the targeted inactivation of the alternative de novo AMP synthesis pathway may be a useful therapeutic strategy in tumors with inactivation of this enzyme. EXPERIMENTAL DESIGN: MTAP gene deletion and protein expression were studied in 64 and 52 primary MCL, respectively, and the results were correlated with clinical behavior. Five MCL cell lines were analyzed for MTAP expression and for the in vitro sensitivity to L-alanosine, an inhibitor of adenylosuccinate synthetase, and hence de novo AMP synthesis. RESULTS: No protein expression was detected in 8 of 52 (15%) tumors and one cell line (Granta 519). Six of these MTAP negative tumors and Granta 519 cell line had a codeletion of MTAP and p16 genes; one case showed a deletion of MTAP, but not p16, and one tumor had no deletions in neither of these genes. Patients with MTAP deletions had a significant shorter overall survival (mean, 16.1 months) than patients with wild-type MTAP (mean, 63.6 months; P < 0.0001). L-Alanosine induced cytotoxicity and activation of the intrinsic mitochondrial-dependent apoptotic pathway in MCL cells. 9-beta-D-Erythrofuranosyladenine, an analogue of 5'-methylthioadenosine, selectively rescued MTAP-positive cells from L-alanosine toxicity. CONCLUSIONS: MTAP gene deletion and lack of protein expression are associated with poor prognosis in MCL and might identify patients who might benefit from treatment with de novo AMP synthesis pathway-targeted therapies.

Mesenchymal chondrosarcoma: prognostic factors and outcome in 113 patients. A European Musculoskeletal Oncology Society study.

BACKGROUND: Mesenchymal chondrosarcoma (MCS) is a distinct, very rare sarcoma with little evidence supporting treatment recommendations. PATIENTS AND METHODS: Specialist centres collaborated to report prognostic factors and outcome for 113 patients. RESULTS: Median age was 30 years (range: 11-80), male/female ratio 1.1. Primary sites were extremities (40%), trunk (47%) and head and neck (13%), 41 arising primarily in soft tissue. Seventeen patients had metastases at diagnosis. Mean follow-up was 14.9 years (range: 1-34), median overall survival (OS) 17 years (95% confidence interval (CI): 10.3-28.6). Ninety-five of 96 patients with localised disease underwent surgery, 54 additionally received combination chemotherapy. Sixty-five of 95 patients are alive and 45 progression-free (5 local recurrence, 34 distant metastases, 11 combined). Median progression-free survival (PFS) and OS were 7 (95% CI: 3.03-10.96) and 20 (95% CI: 12.63-27.36) years respectively. Chemotherapy administration in patients with localised disease was associated with reduced risk of recurrence (P=0.046; hazard ratio (HR)=0.482 95% CI: 0.213-0.996) and death (P=0.004; HR=0.445 95% CI: 0.256-0.774). Clear resection margins predicted less frequent local recurrence (2% versus 27%; P=0.002). Primary site and origin did not influence survival. The absence of metastases at diagnosis was associated with a significantly better outcome (P<0.0001). Data on radiotherapy indications, dose and fractionation were insufficiently complete, to allow comment of its impact on outcomes. Median OS for patients with metastases at presentation was 3 years (95% CI: 0-4.25). CONCLUSIONS: Prognosis in MCS varies considerably. Metastatic disease at diagnosis has the strongest impact on survival. Complete resection and adjuvant chemotherapy should be considered as standard of care for localised disease.

Protein expression analysis of ALCAM and CEACAM6 in breast cancer metastases reveals significantly increased ALCAM expression in metastases of the skin.

AIMS: For prediction and understanding of underlying mechanisms of organ-specific metastases, various gene and protein expression signatures have been identified in primary breast carcinomas. These expression signatures often include several genes coding for adhesion molecules, such as activated leucocyte cell adhesion molecule (ALCAM/CD166) and carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6), both of which may play an important role in the development of distant metastases because of their adherent properties. Owing to their predominantly membranous localisation, they are also considered to have certain therapeutic potential. Apart from expression data obtained in the primary tumour, data for gene and protein expression patterns in distant breast cancer metastases are rare. Therefore this study focuses on analysing the distribution of ALCAM and CEACAM6 protein expression in breast cancer metastases from different sites. METHODS: Immunohistochemical staining for ALCAM and CEACAM6 in 117 breast cancer metastases derived from liver (n=24), lung (n=19), brain (n=21), bone (n=36) and skin (n=17) was performed. RESULTS: Immunoreactive scores (IRS) for ALCAM in all metastases except skin metastases ranged from 2.63 to 5.10 (membranous) and 2.79 to 3.67 (cytoplasmic), showing a positive correlation with each other (r=0.690, p<0.001). In skin metastases, ALCAM expression was significantly stronger (membranous IRS, 8.76; cytoplasmic IRS, 7.12; p<0.001). Mean staining intensity for CEACAM6 was IRS 3.88. No or weak CEACAM6 and ALCAM staining (IRS 0-3) was seen in 53% vs 27% of all metastases. CONCLUSIONS: Compared with CEACAM6, ALCAM showed significantly stronger protein expression in breast cancer skin metastases compared with metastases in all other sites.

A cytomorphological and immunohistochemical profile of aggressive B-cell lymphoma: high clinical impact of a cumulative immunohistochemical outcome predictor score.

We analyzed morphological and immunohistochemical features in 174 aggressive B-cell lymphomas of nodal and extranodal origin. Morphological features included presence or absence of a follicular component and cytologic criteria according to the Kiel classification, whereas immunohistochemical studies included expression of CD10, BCL-2, BCL-6, IRF4/MUM1, HLA-DR, p53, Ki-67 and the assessment of plasmacytoid differentiation. Patients were treated with a CHOP-like regimen. While the presence or absence of either CD10, BCL-6 and IRF4/MUM1 reactivity or plasmacytoid differentiation did not identify particular cytomorphologic or site-specific subtypes, we found that expression of CD10 and BCL-6, and a low reactivity for IRF4/MUM1 were favourable prognostic indicators. In contrast, BCL-2 expression and presence of a monotypic cytoplasmic immunoglobulin expression was associated with an unfavourable prognosis in univariate analyses. Meta-analysis of these data resulted in the development of a cumulative immunohistochemical outcome predictor score (CIOPS) enabling the recognition of four distinct prognostic groups. Multivariate analysis proved this score to be independent of the international prognostic index. Such a cumulative immunohistochemical scoring approach might provide a valuable alternative in the recognition of defined risk types of aggressive B-cell lymphomas.

Genomic deletion and promoter methylation status of Hypermethylated in Cancer 1 (HIC1) in mantle cell lymphoma.

Mantle cell lymphomas (MCL), characterized by the t(11;14)(q13;q32), frequently carry secondary genetic alterations such as deletions in chromosome 17p involving the TP53 locus. Given that the association between TP53-deletions and concurrent mutations of the remaining allele is weak and based on our recent report that the Hypermethylated in Cancer 1 (HIC1) gene, that is located telomeric to the TP53 gene, may be targeted by deletions in 17p in diffuse large B-cell lymphoma (DLBCL), we investigated whether HIC1 inactivations might also occur in MCL. Monoallelic deletions of the TP53 locus were detected in 18 out of 59 MCL (31%), while overexpression of p53 protein occurred in only 8 out of 18 of these MCL (44%). In TP53-deleted MCL, the HIC1 gene locus was co-deleted in 11 out of 18 cases (61%). However, neither TP53 nor HIC1 deletions did affect survival of MCL patients. In most analyzed cases, no hypermethylation of the HIC1 exon 1A promoter was observed (17 out of 20, 85%). However, in MCL cell lines without HIC1-hypermethylation, the mRNA expression levels of HIC1 were nevertheless significantly reduced, when compared to reactive lymph node specimens, pointing to the occurrence of mechanisms other than epigenetic or genetic events for the inactivation of HIC1 in this entity.