A validated new histological classification for intervertebral disc degeneration.

UNLABELLED: Histology is an important outcome variable in basic science and pre-clinical studies regarding intervertebral disc degeneration (IVD). Nevertheless, an adequately validated histological classification for IVD degeneration is still lacking and the existing classifications are difficult to use for inexperienced observers. OBJECTIVE: Therefore the aim of this study was to develop and to validate a new histological classification for IVD degeneration. Moreover, the new classification was compared to the frequently used non-validated classification. METHODS: The new classification was applied to human IVD sections. The sections were scored twice by two independent inexperienced observers, twice by two experienced IVD researchers and once by a pathologist. For comparison, the sections were also scored according to the classification described by Boos et al. by two experienced IVD researchers. Macroscopic grading according Thompson et al., glycosaminoglycan (GAG) content and age were used for validation. RESULTS: The new classification had an excellent intra- and a good inter-observer reliability. Intraclass Correlation Coefficients (ICC) were 0.83 and 0.74, respectively. Intra- and inter-observer reliability were comparable for experienced and inexperienced observers. Statistically significant correlations were found between the new classification, macroscopic score, GAG content in the nucleus pulposus (NP) and age; Correlation coefficient (CC) 0.79, -0.62 and 0.68, respectively. The CCs of the Boos classification were all lower compared to the new classification. CONCLUSION: the new histological classification for IVD degeneration is a valid instrument for evaluating IVD degeneration in human IVD sections and is suitable for inexperienced and experienced researchers.

Micro-CT quantification of subchondral endplate changes in intervertebral disc degeneration.

BACKGROUND: The intervertebral disc (IVD) is dependent on nutrient provision through a cartilage layer with underlying subchondral bone, analogous to joint cartilage. In the joint, subchondral bone remodeling has been associated with osteoarthritis (OA) progression due to compromised nutrient and gas diffusion and reduced structural support of the overlaying cartilage. However, subchondral bone changes in IVD degeneration have never been quantified before. OBJECTIVE: The aim of this study is to determine the subchondral bone changes at different stages of IVD degeneration by micro-CT. METHODS: Twenty-seven IVDs including the adjacent vertebral endplates were obtained at autopsy. Midsagittal slices, graded according the Thompson score, were scanned. Per scan 12 standardized cylindrical volumes of interest (VOI) were selected. Six VOIs contained the bony endplate and trabeculae (endplate VOIs) and six accompanying VOIs only contained trabecular bone (vertebral VOIs). Bone volume as percentage of the total volume (BV/TV) of the VOI, trabecular thickness (TrTh) and connectivity density (CD) were determined. RESULTS: An increase in BV/TV and TrTh was found in endplate VOIs of IVDs with higher Thompson score whereas these values remained stable or decreased in the vertebral VOIs. CONCLUSION: The increase in bone volume combined with the increase in TrTh in endplate VOIs strongly suggest that the subchondral endplate condenses to a more dense structure in degenerated IVDs. This may negatively influence the diffusion and nutrition of the IVD. The endplate differences between intact and mild degenerative IVDs (grade II) indicate an early association of subchondral endplate changes with IVD degeneration.

Expression of the serpin serine protease inhibitor 6 protects dendritic cells from cytotoxic T lymphocyte-induced apoptosis: differential modulation by T helper type 1 and type 2 cells.

Dendritic cells (DCs) play a central role in the immune system as they drive activation of T lymphocytes by cognate interactions. However, as DCs express high levels of major histocompatibility complex class I, this intimate contact may also result in elimination of DCs by activated cytotoxic T lymphocytes (CTLs) and thereby limit induction of immunity. We show here that immature DCs are indeed susceptible to CTL-induced killing, but become resistant upon maturation with anti-CD40 or lipopolysaccharide. Protection is achieved by expression of serine protease inhibitor (SPI)-6, a member of the serpin family that specifically inactivates granzyme B and thereby blocks CTL-induced apoptosis. Anti-CD40 and LPS-induced SPI-6 expression is sustained for long periods of time, suggesting a role for SPI-6 in the longevity of DCs. Importantly, T helper 1 cells, which mature DCs and boost CTL immunity, induce SPI-6 expression and subsequent DC resistance. In contrast, T helper 2 cells neither induce SPI-6 nor convey protection, despite the fact that they trigger DC maturation with comparable efficiency. Our data identify SPI-6 as a novel marker for DC function, which protects DCs against CTL-induced apoptosis.

Hypertrophic differentiation and calcification during intervertebral disc degeneration.

BACKGROUND: In degenerative intervertebral discs (IVDs) collagen type X expression and calcifications have been demonstrated, resembling advanced osteoarthritis (OA), which is associated with hypertrophic differentiation, characterized by the production of collagen type X, Runt-related transcription factor 2 (Runx2), osteoprotegerin (OPG), alkaline phosphatase (ALP) and calcifications. OBJECTIVE: The aim of this study was to determine if hypertrophic differentiation occurs during IVD degeneration. METHODS: IVDs from all Thompson degeneration grades were prepared for histology, extraction of nucleus pulposus (NP) and annulus fibrosis (AF) tissue (N=50) and micro-CT (N=27). The presence of collagen type X, OPG and Runx2 was determined by immunohistochemistry, with OPG levels also determined by Enzyme-linked immunosorbent assay (ELISA). The presence of calcification was determined by micro-CT, von Kossa and Alizarin Red staining. RESULTS: Immunohistochemical staining for collagen type X, OPG, Runx2 appeared more intense in the NP of degenerative compared to healthy IVD samples. OPG levels correlated significantly with degeneration grade (NP: P<0.000; AF: P=0.002) and the number of microscopic calcifications (NP: P=0.002; AF: P=0.008). The extent of calcifications on micro-CT also correlated with degeneration grade (NP: P<0.001, AF: P=0.001) as did von Kossa staining (NP: P=0.015, AF: P=0.016). ALP staining was only incidentally seen in the transition zone of grades IV and V degenerated IVDs. CONCLUSION: This study for the first time demonstrates that hypertrophic differentiation occurs during IVD degeneration, as shown by an increase in OPG levels, the presence of ALP activity, increased immunopositivity of Runx2 and collagen type X.

Ectopic expression of the serine protease inhibitor PI9 modulates death receptor-mediated apoptosis.

Apoptosis is a highly controlled process, whose triggering is associated with the activation of caspases. Apoptosis can be induced via a subgroup of the tumor necrosis factor (TNF) receptor superfamily, which recruit and activate pro-caspase-8 and -10. Regulation of apoptosis is achieved by several inhibitors, including c-FLICE-inhibitory protein, which prevents apoptosis by inhibiting the pro-apoptotic activation of upstream caspases. Here we show that the human intracellular serine protease inhibitor (serpin), protease inhibitor 9 (PI9), inhibits TNF-, TNF-related apoptosis-inducing ligand- and Fas ligand-mediated apoptosis in certain TNF-sensitive cell lines. The reactive center P1 residue of PI9 was required for this inhibition since PI9 harboring a Glu --> Ala mutation in its reactive center failed to impair death receptor-induced cell death. This suggests a classical serpin-protease interaction. Indeed, PI9 inhibited apoptotic death by directly interacting with the intermediate active forms of caspase-8 and -10. This indicates that PI9 can regulate pro-apoptotic apical caspases.

DNA copy number status is a powerful predictor of poor survival in endocrine pancreatic tumor patients.

The clinical behavior of endocrine pancreatic tumors (EPTs) is difficult to predict in the absence of metastases or invasion to adjacent organs. Several markers have been indicated as potential predictors of metastatic disease, such as tumor size > or =2 cm, Ki67 proliferative index > or =2%, cytokeratin (CK) 19 status, and recently in insulinomas, chromosomal instability (CIN). The goal of this study was to evaluate the value of these markers, and in particular of the CIN, to predict tumor recurrence or progression and tumor-specific death, using a series of 47 insulinomas and 24 non-insulinoma EPTs. From these EPT cases, a genomic profile has been generated and follow-up data have been obtained. The proliferative index has been determined in 68 tumors and a CK19 expression pattern in 50 tumors. Results are statistically analyzed using Kaplan-Meier plots and the log-rank statistic. General CIN, as well as specific chromosomal alterations such as 3p and 6q loss and 12q gain, turned out to be the most powerful indicators for poor tumor-free survival (P< or =0.0004) and tumor-specific death (P< or =0.0113) in insulinomas. The CIN, chromosome 7q gain, and a proliferative index > or =2% were reliable in predicting a poor tumor-free survival in non-insulinoma EPTs (P< or =0.0181, whereas CK19 expression was the most optimal predictor of tumor-specific death in these tumors. In conclusion, DNA copy number status is the most sensitive and efficient marker of adverse clinical outcome in insulinomas and of potential interest in non-insulinoma EPTs. As a consequence, this marker should be considered as a prognosticator to improve clinical diagnosis, most practically as a simple multi-target test.

Prognostic significance of activated cytotoxic T-lymphocytes in primary nodal diffuse large B-cell lymphomas.

Clinical outcome in diffuse large B-cell lymphoma (DLBCL) remains unpredictable, despite the identification of clinical prognostic parameters. Here, we investigated in pretreatment biopsies of 70 patients with DLBCL whether numbers of activated cytotoxic T-lymphocytes (CTLs), as determined by the percentage of CD3-positive lymphocytes with granzyme B (GrB) expression, have similar prognostic value as found earlier in Hodgkin's lymphoma and anaplastic large-cell lymphoma and whether loss of major histocompatibility complex (MHC)-I molecules or expression of the GrB antagonist protease inhibitor 9 (PI9) may explain immune escape from CTL-mediated cell death. Independent of the International Prognostic Index (IPI), the presence of >/=15% activated CTLs was strongly associated with failure to reach complete remission, with a poor progression-free and overall survival time. Downregulation of MHC-I light- and/or heavy-chain expression was found in 41% of interpretable cases and in 19 of 56 interpretable cases PI9 expression was detected. We conclude that a high percentage of activated CTLs is a strong, IPI independent, indicator for an unfavorable clinical outcome in patients with primary nodal DLBCL. Although in part of DLBCL expression of PI9 and loss of MHC-I expression was found, providing a possible immune-escape mechanism in these cases, no correlation with clinical outcome was found.

Molecular assays for the diagnosis of minimal residual head-and-neck cancer: methods, reliability, pitfalls, and solutions.

The prognosis of cancer patients is determined by the radicalness of treatment: residual tumor cells will grow out and develop in manifest local recurrences, regional recurrences, and distant metastases. Classical diagnostic methods such as radiology and histopathology have limited sensitivities, and only by molecular techniques can minimal residual disease be detected. In tissue samples containing the normal tissue counterpart of a tumor, only tumor-specific markers can be exploited, whereas in other samples, tissue-specific markers can be used. At present, there are two main methodologies in use, one based on antigen-antibody interaction and the other based on amplified nucleic acids. The most commonly used nucleic acid markers are mutations or alterations in tumor DNA (tumor-specific markers) or differentially expressed mRNA (tissue-specific markers). Many reports and reviews have been published on the assessment of minimal residual disease by molecular markers, showing either positive or negative clinical correlations. One of the main reasons for these contradictory findings is the technical difficulty in finding the small numbers of tumor cells in the large number of normal cells, which necessitates sensitivities of the assays up to 1 tumor cell in 2 x 10(7) normal cells. These assays often are complex, demand considerable experience, and usually are laborious. In this review, we will address a number of the technical issues related to molecular assays for tumor cell detection that make use of nucleic acids as markers. Many difficulties in data interpretation are at least in part because of technical details that might have been solved by the incorporation of one or more appropriate controls. We hope that this review clarifies a number of these issues and help clinicians and investigators interested in this field to understand and weigh the contradictory findings in the published studies. This will help move the field forward and facilitate clinical implementation.

Persistence of genetically altered fields in head and neck cancer patients: biological and clinical implications.

In 1953, Slaughter et al. [D. P. Slaughter et al., Cancer (Phila.), 6: 963-968, 1953] proposed the concept of field cancerization in patients with squamous cell carcinoma of the head and neck (HNSCC) and discussed its clinical significance for the development of second primary tumors and local recurrences. To define the process of field cancerization and its putative clinical implications, we analyzed genetic aberrations in HNSCC and the accompanying macroscopically normal mucosa. In 28 HNSCC patients, loss of heterozygosity was determined in tumor and five noncontiguous mucosal biopsies using eight microsatellite markers at 9p, 3p, and 17p. For patients who showed loss of heterozygosity in their mucosal biopsies, all margins of the surgical specimen were subsequently analyzed to determine the extension of the field. In these cases, additional markers at 8p, 13q, and 18q as well as p53 mutations were included to determine subclonal differences between field and tumor. Genetically altered fields were detected in 36% (10 of 28) of the HNSCC patients. The field varied in size between patients and consisted of genetically different subclones. In 7 of 10 cases, the field extended into the surgical margins. One particular patient with a genetically altered field in a surgical margin developed a local recurrence after 28 months of follow-up. Microsatellite analysis showed that this recurrence had more molecular markers in common with the nonresected premalignant field than with the original tumor, suggesting that this persistent field has progressed further into a new malignancy. Our data show that genetically altered mucosa remains after treatment in a significant proportion of HNSCC patients, which may explain in part the high frequency of local recurrences and second primary tumors. Adequate identification and risk assessment of these genetically altered fields may have profound implications for future patient management.

Most primary cutaneous CD30-positive lymphoproliferative disorders have a CD4-positive cytotoxic T-cell phenotype.

Primary cutaneous CD30-positive (anaplastic) large T-cell lymphomas and lymphomatoid papulosis are closely related types of cutaneous T-cell lymphoma with a favorable prognosis. The neoplastic T cells in these conditions have the phenotype of activated CD3+, CD4+, CD8-, CD30+ skin homing T cells, but their normal counterpart has not yet been defined. To further characterize the cellular origin of the neoplastic T cells, skin biopsies from 14 patients with primary cutaneous CD30-positive (anaplastic) large T-cell lymphomas, nine patients with lymphomatoid papulosis, and six patients with primary cutaneous CD30-negative pleomorphic large T-cell lymphomas were stained with monoclonal antibodies against cytotoxic cell-associated molecules granzyme B and T-cell restricted intracellular antigen. In nine of nine lymphomatoid papulosis and in 10 of 14 CD30-positive primary cutaneous large T-cell lymphomas, expression of granzyme B and T-cell restricted intracellular antigen by variable numbers of neoplastic cells was found. Expression of granzyme B by the neoplastic CD30-positive T cells was confirmed by double-staining for granzyme B and CD30 (three cases) and by the detection of granzyme B mRNA using RNA in situ hybridization (one case). In most cases equal numbers of granzyme-B-positive and T-cell restricted intracellular antigen positive tumor cells were observed. In five of six CD30-negative primary cutaneous large T-cell lymphomas the neoplastic cells did not express these proteins, whereas in one case a sporadic positive tumor cell was found. These results demonstrate that, in contrast to primary cutaneous CD30-negative pleomorphic large T-cell lymphomas, the neoplastic cells in most primary cutaneous CD30-positive (anaplastic) large T-cell lymphomas and lymphomatoid papulosis have a unique CD4+, CD8-, cytotoxic T-cell phenotype.

Production and characterization of monoclonal antibodies raised against recombinant human granzymes A and B and showing cross reactions with the natural proteins.

The human serine proteases granzymes A and B are expressed in cytoplasmic granules of activated cytotoxic T lymphocytes and natural killer cells. Recombinant granzyme A and granzyme B proteins were produced in bacteria, purified and then used to raise specific mouse monoclonal antibodies. Seven monoclonal antibodies (mAb) were raised against granzyme A, which all recognized the same or overlapping epitopes. They reacted specifically in an immunoblot of interleukin-2 (IL-2) stimulated PBMNC with a disulfide-linked homodimer of 43 kDa consisting of 28 kDa subunits. Seven mAb against granzyme B were obtained, which could be divided into two groups, each recognizing a different epitope. On an immunoblot, all mAb reacted with a monomer of 33 kDa protein. By immunohistochemistry, these mAb could be used to detect granzymes A and B expression in activated CTL and NK cells. The availability of these mAb may facilitate studies on the role of human cytotoxic cells in various immune reactions and may contribute to a better understanding of the role of granzymes A and B in the cytotoxic response in vivo.

Lack of granzyme expression in T lymphocytes indicates poor cytotoxic T lymphocyte activation in human papillomavirus-associated cervical carcinomas.

Changes in major histocompatibility complex (MHC) class I expression in neoplastic cells are frequently observed in human papillomavirus type 16 (HPV16)-associated cervical carcinomas. In order to investigate whether this affects cytotoxic T-cell (CTL) activation, 20 HPV16-positive cervical carcinomas with variable MHC expression were analyzed immunohistochemically for the expression of granzyme B and interleukin-2 receptor (IL-2R). The results revealed that most carcinomas show strong CD3+ T-lymphocyte infiltrates. In nine of these cases CD8+ cells outnumbered the CD4+ cells, whereas in the remaining cases equal amounts of CD4+ and CD8+ cells were found. Double staining revealed that CD3+ granzyme B+ cells were not detected in 19 out of 20 cervical lesions, whereas in one carcinoma an occasional cluster of granzyme B+ T cells was observed. Positive controls, including genital warts and renal allograft rejections, showed granzyme B+ T cells. In agreement with this observation was the extremely low frequency of IL-2R+ T cells in the carcinomas tested, while warts contained IL-2R+ lymphocytes. The data indicate that cytotoxic (CD8+) T cells in cervical carcinomas are not activated, as demonstrated by the lack of granzyme B and IL-2R expression in the T cells.

Case report of a patient with an intimal sarcoma of the pulmonary trunk presenting as a pulmonary embolism.

A fatal case of an 89-year-old woman with an intimal sarcoma obstructing the pulmonary trunk and an open foramen ovale is presented. Clinical symptoms, physical examination and further evaluation originally raised suspicion of a pulmonary embolism. Recent classification systems, specific radiological and pathological characteristics of sarcomas of the pulmonary trunk are discussed.

[Diagnostic image (97). A woman with septicemia due to the small intestinal infarction]. / Diagnose in beeld (97). Een vrouw met sepsis door dunnedarminfarcering.

A 69-year-old woman who was treated for a spindle cell carcinoma of the upper jaw developed tumour emboli causing ischaemia and infarction of fingertips, small intestine, spleen, pancreas and kidneys.

[Lung cancer staging by endobronchial ultrasound with transbronchial needle aspiration]. / Endobronchiale ultrasonografie met transbronchiale naaldaspiratie bij stadiëring van longcarcinomen.

OBJECTIVE: To determine the diagnostic yield of endobronchial ultrasound with transbronchial needle aspiration (EBUS-TBNA) and to investigate the number of cervical mediastinoscopies that could be avoided when this technique was used as the initial modality in the invasive mediastinal staging of lung cancer. DESIGN: Retrospective cohort study. METHOD: At the St. Antonius Hospital, Nieuwegein, the Netherlands, results from all patients who had undergone EBUS-TBNA for mediastinal staging in lung cancer from September 2008 to January 2011 were collected. If metastases in the mediastinal lymph nodes had been demonstrated by EBUS-TBNA, no indication for additional mediastinoscopy ensued. The diagnostic yield of EBUS-TBNA as well as the number of mediastinoscopies that had been avoided, were calculated. RESULTS: EBUS-TBNA had been used for mediastinal staging in lung cancer in 77 patients. In 39 of these 77 patients (51%), mediastinal lymph node metastases was found using EBUS-TBNA and mediastinoscopy could thus be avoided. In 9 out of 38 (24%) patients whose EBUS-TBNA cytology results were found to be either benign or not representative, mediastinoscopy or endoscopic ultrasound eventually did reveal mediastinal lymph node metastases. In 13 of these 38 patients (34%), no additional cytologic or histologic testing was performed. Diagnostic yield was calculated for the two scenarios. The sensitivity and negative-predictive values for EBUS-TBNA were 64-81% and 42-76%, respectively. CONCLUSION: In more than 50% of lung cancer patients with suspected mediastinal lymph node metastases, cervical mediastinoscopy can be avoided when EBUS-TBNA is used. This examination is the technique of first choice for the invasive staging of the mediastinum in lung cancer, but it can not replace mediastinoscopy completely.

Human Papillomavirus and Oropharyngeal Squamous Cell Carcinoma: A Case-Control Study regarding Tobacco and Alcohol Consumption.

We aimed to determine the role of HPV in the pathogenesis and outcome of oropharyngeal squamous cell carcinoma (OSCC) in lifelong nonsmoking and nondrinking patients. A case-case analysis was performed to compare the presence of HPV-DNA in tumor cells of 16 nonsmoking and nondrinking with 16 matched smoking and drinking patients (matching criteria: age at incidence, gender, tumor sublocation, tumor stage). HPV was detected using 2 PCR tests, FISH analysis, and p16(INK4A) immunostaining. Nonsmoking and nondrinking patients had more HPV-positive tumors than smoking and drinking patients (n = 12; 75% versus n = 2; 13%; P < 0.001). All HPV-positive tumors showed p16(INK4A) overexpression, and 1 HPV-negative tumor had p16(INK4A) overexpression, (P < 0.001). Overall survival and disease-specific survival were higher for HPV-positive compared to HPV-negative cases (P = 0.027, P = 0.039, resp.). In conclusion, HPV is strongly associated with OSCC of nonsmoking and nondrinking patients. Specific diagnostic and therapeutic actions should be considered for these patients to achieve a better prognosis.

Hair follicles as a niche of Staphylococcus aureus in the nose; is a more effective decolonisation strategy needed?

Staphylococcus aureus is the major cause of surgical site infections, and meticillin-resistant S. aureus (MRSA) is increasingly accounting for infections worldwide. Preventing surgical site infections by screening and decolonising positive patients reduces the number of infections, but does not completely eradicate the risk. A balance between prevention, costs and the chance of mupirocin-resistant S. aureus needs to be evaluated and decolonisation strategies optimised. It is essential to know the site of S. aureus during colonisation. In this study, for the first time the exact location of S. aureus in the human nose was determined using a histological approach. We showed the presence of S. aureus in the cornified layer of squamous epithelium, associated keratin and mucous debris and within hair follicles in the vestibulum nasi. The presence of S. aureus in hair follicles suggests that this could be the niche from which relapses occur after decolonisation. Decolonisation strategies might have to be reconsidered.

Ear piercing techniques and their effect on cartilage, a histologic study.

BACKGROUND: The popularity of high ear piercing has led to an increased incidence of perichondritis. Damage to the relatively avascular cartilage will make the ear prone to infection. The literature suggests that a piercing gun, mainly used by jewellers to pierce the lobule, may give excessive cartilaginous damage. Therefore some authors favour the piercing needle, as used in piercing studios. But until now, no comparative histological studies have been performed. PURPOSE OF STUDY: To evaluate the extent of damage to ear cartilage using different piercing techniques. METHODS: Twenty-two fresh human cadaver ears were pierced using two spring loaded piercing guns (Caflon and Blomdahl), one hand force system (Studex) and a piercing needle (16G i.v. catheter). Extent of damage to the perichondrium and cartilage was quantified using a transverse section along the pin tract and compared between the different methods. RESULTS: The pattern of injury was similar in all techniques, showing perichondrium stripped from the cartilage around the pin tract, with most damage present on the exit site (mean length of 0.43 mm). Cartilage fractures and loose fragments were present over a mean length of 0.21 mm. No significant difference in the amount of injury between the different techniques was observed. CONCLUSIONS: In contradiction with assumptions in the literature, all piercing methods give the same extent of damage to cartilage and perichondrium. Each method is expected to have the same risk for perichondritis, thus in the prevention of post-piercing perichondritis focus should be on other factors such as hygiene and after-care.

Increased MMP-2 activity during intervertebral disc degeneration is correlated to MMP-14 levels.

Intervertebral disc (IVD) degeneration is associated with the increased expression of several matrix metalloproteinases (MMPs), in particular MMP-2. However, little is known about the actual activity of MMP-2 in healthy and degenerated discs, or what mechanisms are involved in its activation. A major activation pathway involves complex formation with MMP-14 and a tissue inhibitor of metalloproteinases-2 (TIMP-2). In a series of 56 human IVDs, obtained at autopsy and graded according to the Thompson score (I-V), we analysed whether MMP-2 activity was increased in different stages of IVD degeneration and to what extent activation was related to the production of MMP-14 and TIMP-2. MMP-2 activation and production were quantified by gelatin zymography. Immunohistochemical staining of MMP-14 and TIMP-2 was quantified with a video overlay-based system. A positive correlation was observed between the amount of active MMP-2 and pro-MMP-2 and degeneration grade (p < 0.001, correlation coefficient (CC) 0.557; and p < 0.001, CC 0.556, respectively). MMP-2 activity correlated positively with MMP-14 and less strongly with TIMP-2 (p = 0.001, CC 0.436; and p = 0.03, CC 0.288, respectively). Moreover, immunopositivity for MMP-14 correlated to degeneration grade (p = 0.002, CC 0.398). IVD degeneration was associated with the activity of MMP-2 and the correlation of its activation with MMP-14 production suggests MMP-14 activates MMP-2 during degeneration. As MMP-14 is capable of activating several other enzymes that are also thought to be involved in IVD degeneration, it may be a key mediator of the degenerative process.

Expression of c-FLIP is primarily detected in diffuse large B-cell lymphoma and Hodgkin's lymphoma and correlates with lack of caspase 8 activation.

AIMS: Inhibition of apoptosis is important in the pathogenesis of lymphomas. c-FLIP, a regulator of caspase 8-mediated apoptosis, plays an important role in protecting normal B and T cells from apoptosis and possibly also in lymphomas. Because of contradictory reports about immunohistochemical detection of c-FLIP expression, the aim was to test the specificity of four antibodies in c-FLIP-transfected cells and subsequently to investigate expression of c-FLIP in different types of lymphoma. METHODS AND RESULTS: Two of four antibodies were specific. In primary lymphomas c-FLIP expression was restricted to Hodgkin's lymphomas (> 90%) and diffuse large B-cell lymphomas (44%). Burkitt lymphomas and indolent B-cell lymphomas were negative in all cases. No expression was detected in primary T-cell lymphomas, although expression was observed in one relapsed ALK+ anaplastic large cell lymphoma. Expression of c-FLIP was inversely correlated with caspase 8 activation. CONCLUSIONS: c-FLIP is important in escape of B cells from apoptosis during normal follicle centre cell reaction and may thus be an important early event in the development of B-cell-derived lymphomas. Moreover, non-specific staining of frequently used antibodies might explain discrepancies in different reports of c-FLIP expression.