Treatment of Experimental Candida Sepsis with a Janus Kinase Inhibitor Controls Inflammation and Prolongs Survival.

Janus kinases (JAK) are intracellular tyrosine kinases that transduce cytokine-mediated signals to the nucleus, promoting gene expression. Cytokines play a major role in microbial sepsis, which is often associated with uncontrolled inflammation leading to death. JAK inhibitors have been used for the treatment of several autoimmune diseases by modulating immune response, but they have never been tested against microbial sepsis. Ruxolitinib is a small-molecule inhibitor of JAK1/2 proteins, which are involved in the downstream signaling pathway of the vast majority of proinflammatory and anti-inflammatory cytokines. We therefore studied the effect of ruxolitinib in a mouse model of sepsis due to Candida albicans. When ruxolitinib therapy (50 mg/kg [of body weight]/day) was started 1 day before infection, the median survival time was reduced by 3 days, the fungal loads in all organs were higher, the inflammation was significantly less, and serum tumor necrosis factor alpha (TNF-α) and interleukin 10 (IL-10) levels and IL-10/TNF-α ratios were higher than in controls. When ruxolitinib therapy (50 to 1.5 mg/kg/day) was started 1 day after infection, an inverted-U relationship was found, with 6.25 mg/kg/day prolonging median survival time by 6 days, resulting in similar fungal loads, less inflammation, and similar cytokine levels but higher IL-10/TNF-α ratios than the controls. The optimal dose of ruxolitinib controlled infection and prolonged survival with less inflammation than in control animals. Administration of JAK inhibitors may be a promising therapeutic adjunct that needs further investigation.

Cardiosphere-Derived Cells Attenuate Inflammation, Preserve Systolic Function, and Prevent Adverse Remodeling in Rat Hearts With Experimental Autoimmune Myocarditis.

BACKGROUND: Cardiosphere-derived cells (CDCs) have yielded promising efficacy signals in early-phase clinical trials of ischemic and nonischemic cardiomyopathy. The potential efficacy of CDCs in acute myocarditis, an inflammatory cardiomyopathy without effective therapy, remains unexplored. Given that CDCs produce regenerative, cardioprotective, anti-inflammatory, and anti-fibrotic effects (all of which could be beneficial in acute myocarditis), we investigated the efficacy of intracoronary delivery of CDCs in a rat model of experimental autoimmune myocarditis. METHODS: Lewis rats underwent induction of experimental autoimmune myocarditis by subcutaneous footpad injection of purified porcine cardiac myosin supplemented with Mycobacterium tuberculosis on days 1 and 7. On day 10, rats were randomly assigned to receive global intracoronary delivery of 500 000 CDCs or vehicle. Global intracoronary delivery was performed by injection of cells or vehicle into the left ventricular (LV) cavity during transient occlusion of the aortic root. Rats were euthanized 18 days after infusion. Cardiac volumes and systolic function were assessed by serial echocardiography, performed on days 1, 10, and 28. Myocardial inflammation, T-cell infiltration, and cardiac fibrosis were evaluated by histology. RESULTS: Experimental autoimmune myocarditis was successfully induced in 14/14 rats that completed follow-up. Left ventricular ejection fraction (LVEF) and volumes were comparable on days 1 and 10 between groups. CDC infusion resulted in increased LVEF (81.5% ± 3% vs 65.4% ± 8%, P < .001) and decreased LV end-systolic volume (43 ± 15 vs 100 ± 24 µL, P < .001) compared to placebo administration at 18 days post-infusion. Cardiosphere-derived cell infusion decreased myocardial inflammation (7.4% ± 7% vs 20.7% ± 4% of myocardium, P = .007), cardiac fibrosis (16.6% ± 13% vs 38.1% ± 3% of myocardium, P = .008), and myocardial T-cell infiltration (30.4 ± 29 vs 125.8 ± 49 cells per field, P = .005) at 18 days post-infusion compared to placebo administration. CONCLUSION: Intracoronary delivery of CDCs attenuates myocardial inflammation, T-cell infiltration, and fibrosis while preventing myocarditis-induced systolic dysfunction and adverse remodeling in rats with experimental autoimmune myocarditis.

Low-grade mucosa-associated lymphoid tissue lymphoma: a retrospective analysis of 97 patients by the Hellenic Cooperative Oncology Group (HeCOG).

BACKGROUND: The aim was to examine characteristics and treatment results of patients with mucosa-associated lymphoid tissue (MALT) non-Hodgkin's lymphomas. PATIENTS AND METHODS: Epidemiological and clinical features of 97 patients with MALT lymphoma from the Hellenic Cooperative Oncology Group registry were analysed retrospectively for their prognostic significance in progression-free survival (PFS) and overall survival (OS). Comparisons were made between patients with gastric and nongastric sites of primary lymphoma and between different therapeutic modalities. RESULTS: Sixty-five patients presented with gastric and 32 with nongastric lymphomas. The most frequent locations of nongastric lymphomas were the bowel, lung and parotid. Gastric lymphomas occurred more frequently in males and younger patients compared with nongastric lymphomas. Seventy-four per cent of patients had early (Ann Arbor stages I-II) and 26% had advanced (stages III-IV) disease. The median PFS for the entire population was 44 months. At 5 years, 47% of patients were progression free and the OS rate was 80%. The most reliable prognostic factor for PFS and OS was the Ann Arbor stage; 5-year PFS was 67% versus 13% and 5-year OS 91% versus 51% for patients with early versus advanced disease, respectively (P < 0.001). Of the patients treated with chemotherapy only, 87% achieved an objective response and 71% complete response. Surgery did not offer survival benefit compared with chemotherapy in localised gastric lymphoma. CONCLUSION: MALT lymphomas represent a distinct disease entity with widespread extranodal origin, indolent clinical course and high chemosensitivity. Ann Arbor stage was the most reliable prognostic and predictive factor.

Eosinophilic granuloma masquerading as aggressive periodontitis.

BACKGROUND: Eosinophilic granuloma (EG) is the mildest and mainly localized form of the clinicopathologic spectrum of Langerhans' cell histiocytosis. It is a destructive osseous lesion characterized by a vast number of eosinophils and histiocytes. The etiology remains unknown. In this paper, a case of EG is presented that was initially diagnosed and treated as aggressive periodontitis (AP). METHODS: Despite treatment procedures, the EG continued to expand very quickly, destroying the lingual cortical bone and the neighboring soft tissues and exhibiting periosteal reaction. Diagnosis of EG was established on the basis of histopathologic and immunohistochemical evaluation. Moreover, certain manifestations in the skeletal and respiratory system were observed. RESULTS: Surgical curettage of the lesions was effective; however, corticosteroids and low-dose radiation were used as adjunctive therapy. CONCLUSION: The rapid progress of eosinophilic granuloma, the diagnostic problems, and the consequences of late diagnosis and treatment are discussed.

Malignant triton tumour of the anterior mediastinum as incidental finding.

A rare case of malignant peripheral nerve sheath tumour with rhabdomyoblastic differentiation (malignant triton tumour) of the anterior mediastinum in a 30-year-old male is reported. The tumour was an incidental finding during the diagnostic work-up following a motor vehicle accident. The patient underwent median sternotomy with a tumour resection performed. Local relapse was suspected one month later, as per the chest CT-scan, and post-operative chemoradiation was applied, which produced a response. Twelve months later the patient is doing well while radiological findings remain invariable. Localization of a triton tumour in the anterior mediastinum is extremely rare, adjuvant treatment is necessary, recurrence frequently occurs and the prognosis is dismal.

A reappraisal of the utility of somatostatin receptor scintigraphy in patients with ectopic adrenocorticotropin Cushing's syndrome.

Ectopic ACTH hypersecretion is a rare cause of Cushing's syndrome. Bronchial carcinoids are the most common neoplasms causing the occult ectopic ACTH syndrome (EAS). Localization of these tumors is often difficult. The diagnostic utility of somatostatin receptor scintigraphy (SRS) in EAS has been studied in a limited number of patients with conflicting results. Herein we report our experience with 12 consecutive cases. Histological confirmation was obtained in nine patients, the majority being bronchial carcinoids. Among the seven patients with histologically confirmed bronchial carcinoids, SRS was performed in six patients. In three patients SRS correctly localized a bronchial carcinoid tumor at presentation. In the remaining three it became positive after 8, 22, and 27 months during follow-up. In two patients SRS was positive without any finding in the corresponding conventional imaging study. In two patients positive computed tomography/magnetic resonance imaging preceded SRS localization. There was no false positive SRS. Among three patients with highly suspected EAS, SRS was positive in one. Both patients with EAS due to medullary thyroid carcinoma had focal positive uptake. In summary, in this study a substantial number of patients had positive tumor localization by SRS. Therefore, SRS is a useful tool in the evaluation of patients with EAS.

Burkitt's lymphoma in Greek adults. A study of the Hellenic co-operative oncology group.

Non-African Burkitt's lymphoma is a rare disease among adults without AIDS. Among 1352 Greek adult patients with non-Hodgkin's lymphoma, 24 cases (1.8%) were classified as Burkitt's (BL) or Burkitt-like (BLL) lymphoma. Eleven cases fulfilled the criteria of BL and 13 of BLL. No statistical differences were found in the general characteristics of the two groups at the time of diagnosis. Extranodal involvement was a common finding in both groups and bulky disease (>10 cm) was observed in almost one half of the patients. The majority of the patients were treated with intensive, although different, protocols. After induction treatment, complete remission (CR) was achieved in 14 patients (60.8%). CR was reached in all cases with stage I-II, while in stage IV the CR rate was 30.4%. The median overall survival was 27 months. The median survival for BL was 13 months compared to 27 months in the BLL group (P=0.34). The data of the present retrospective analysis, indicated that there were not significant clinical differences between BL and BLL variants. Since BLL is still a non-reproducible category in the REAL classification, all BL variants must be treated uniformly with intensive protocols.

Primary biliary cirrhosis (PBC): antigen-presenting cells differ in their distribution in early and late stage PBC and involve the ductal, but not the ductular compartment.

We have studied the distribution patterns of antigen-presenting cells (APCs) in different stages of primary biliary cirrhosis (PBC). 58% of cases with early PBC (stages I and II) exhibited dendritic APCs (S-100+, HLA-DR+, KiMlp+) in bile duct epithelia. In contrast, APCs, were not detected in ductular proliferations occurring in late PBC (stages III and IV), but occurred in portal tracts and piecemeal necroses. There was a correlation between the presence of APCs and HLA-DR expression in bile ducts but, in contrast to former studies, we noted a heterogeneous ductal HLA expression. These observations support the hypothesis that: 1) APC distribution in PBC may change as a function of stage, involving hepatic parenchyma in late PBC; 2) ductular epithelia may not represent a target for immune attack, because APCs do not accumulate in these structures; and 3) HLA expression in bile ducts may be heterogeneous, suggesting one mechanism why bile duct destruction in PBC does not take place in a synchronous way.

Expression of p53, p21/waf1, bcl-2, bax, Rb and Ki67 proteins in Hodgkin's lymphomas.

The aim was to investigate the combined immunoexpression of p53, p21, bcl-2, bax, Rb and Ki67 proteins in Hodgkin's lymphomas (HL) and correlate expression patterns with the histotype and the Epstein-Barr Virus (EBV) status. Paraffin-sections from 56 cases of HL (18 nodular sclerosis and 38 mixed cellularity) and from ten "reactive" lymph nodes were investigated. P53, p21, bcl-2, bax, Rb and Ki67 proteins were detected in Hodgkin and Reed-Sternberg (HRS) cells in 35/56, 56/56, 24/56, 23/56, 56/56 and 56/56 cases of HL, respectively. No correlation was found between the expression of each protein and the EBV status or the histotype of HL. Comparison between p53 and p21 staining revealed two patterns: a) p53+/p21+ (35 cases); and b) p53-/p21+ (21 cases). The pattern p53+/p21+ suggests wild type p53 protein able to induce the expression of p21 while the p53-/p21+ pattern suggests p53-independent p21 expression. These results are consistent with the interpretation that inactivating p53 gene mutations may be rare in HL. Comparison between bcl-2 and bax staining showed a statistically significant relationship (p<0.001) for coexpression (19 cases) or absence of expression of both proteins (28 cases) in HRS cells. In contrast, bax expression was observed in most lymphoid cells in all "reactive" lymph nodes. Since the proapoptotic bax protein may act as tumour suppressor it is possible that the absence of this protein in HRS cells in a substantial proportion of HL may confer growth advantage and play a role in their pathogenesis. This could suggest bax gene alterations in some HL since in other studies acute lymphoblastic leukaemia cell lines demonstrate bax gene mutations with loss of bax immunoexpression. Another possibility is that reduced bax expression may be due to post transcriptional regulation, as was described in lymphoma cell lines. Comparison between Rb and Ki67 staining disclosed two main deviations from the normal parallel relationship in reactive lymph nodes: a) 2 cases with low Rb and high Ki67 expression possibly reflecting loss of Rb expression due to chromosome loss or to other abnormalities in the structure or the expression of Rb gene; and b) 9 cases with high RB and low Ki67 possible reflecting an attempt of Rb protein in excess to induce cell cycle arrest. Taken together, our findings provide combined immunohistological evidence for deregulated expression of cell-cycle and apoptosis-related proteins, that may play a role in the pathogenesis of HL.

Immunohistochemical expression of p53, p21/waf1, rb, p16, cyclin D1, p27, Ki67, cyclin A, cyclin B1, bcl2, bax and bak proteins and apoptotic index in normal thymus.

The immunohistochemical expression of p53, p21, Rb, p16, cyclin D1, Ki67, cyclin A, cyclin B1, p27, bcl2, bax, and bak proteins and the apoptotic index (Al) were investigated in 20 normal thymuses (8 adults, 3 adolescents, 5 infants and 4 newborns). The expressions of Rb, Ki67, cyclin A and cyclin B1 were overlapping, being high in the cortex with a tendency for decreased expression toward the medulla. Apoptotic cells were mainly detected in the cortex and the corticomedullary junction, rarely being present in Hassall's corpuscles. The mean values of Ki67, cyclin A, and cyclin B1 expression in thymuses were 77.2%, 32.2% and 21.4% (newborns), 62.4%, 33.7% and 18.5% (infants), 56.9%, 23.4% and 18.9% (adolescents) and 38.7%, 21.7% and 14.6% (adults), respectively. The mean values of AI in thymuses from newborns, infants, adolescents and adults were 1.4%, 2.9%, 2.7% and 3.8%, respectively. This decrease in proliferation and increase in apoptosis may account for the process of thymic involution. P16 expression was widespread with most of Hassall's corpuscles being p16-positive. P16-positive cells and Hassall's corpuscles increased with the increase in age, in keeping with the suggested role of p16 in cellular senescence. P27 expression was undetectable in subcapsular thymocytes with a tendency for increased expression toward the medulla. The expressions of Ki67, cyclin A and cyclin B1 were inversly related with that of p27, consistent with previous evidence that p27 concentration is reduced when the cell-cycle progresses. P21 and much less frequently p53 proteins were mainly detected in a part of the subcapsular cortical epithelial cells. These findings suggest that a) in thymocytes, the apoptotic pathway is mostly p53-independent and the function of p21 as a negative regulator of the cell cycle must be redundant to other negative regulators, such as p16 and p27 which were abundantly detected in thymocytes and b) in some thymic epithelial cells, the p21 expression may be induced by p53, but in most of them seems to be p53-independent. Most of Hassall's corpuscles were p21-positive, consistent with previous evidence that these structures represent end stages of maturation of thymic medullary epithelium and that p21 protein is involved in the process of terminal differentiation. Cyclin D1 positivity was found in some macrophages. Bcl2 expression was mainly seen in medullary thymocytes, reflecting the surviving thymocytes in this region. The expressions of Bax and bak were more widespread in both the medulla and cortex, suggesting that these proteins play a broader role than bcl2 in the regulation of thymic apoptosis.

Immunohistochemical expression of the p53, mdm2, p21/Waf-1, Rb, p16, Ki67, cyclin D1, cyclin A and cyclin B1 proteins and apoptotic index in T-cell lymphomas.

Fifty-seven cases of T-cell lymphomas (TCL) including 5 lymphoblastic (T-LBL) and 52 peripheral TCL (PTCL) were analyzed by immunohistochemistry for the expression of p53, mdm2, p21, Rb, cyclin D1, cyclin A, cyclin B1, and Ki67/MIB1 proteins and 39/52 PTCL were also analyzed for the expression of p16 protein and for the presence of apoptotic cells by the TUNEL method. The aim was to search for abnormal immunoprofiles of p53 and Rb growth control pathways and to determine the proliferative activity and the apoptotic index of TCL. Abnormal overexpression of p53, p21 and mdm2, in comparison to normal lymph nodes, was found in 12/57, 10/57 and 2/57 cases of TCL, respectively. Abnormal loss of Rb and p16 expression was found in 1/57 and 2/39 cases, respectively, whereas abnormal overexpression of cyclin D1 was not detected in any of the 57 cases. Our data revealed entity-related p53/p21/mdm2 phenotypes. Indeed, most nodal and cutaneous CD30+ anaplastic large cell lymphomas (ALCL) showed concomitant overexpression of p53 and p21 proteins (7/8 cases), and mdm2 was overexpressed in 2 p53-positive nodal ALCL. In contrast, overexpression of p53 was found in 3/17 cases of nodal peripheral TCL unspecified (PTCL-UC) and 2/7 non-ALCL cutaneous pleomorphic TCL. Overexpression of p21 protein was detected in 2/3 p53-positive PTCL-UC and in 1/2 p53-positive non-ALCL cutaneous pleomorphic TCL. Finally, all the remaining 25 cases of TCL did not show p53 and p21 overexpression. Overall, the p53+/p21+ phenotype in 10/57 TCL suggests wild-type p53 capable of inducing p21 expression. The highest apoptotic index (AI) was found in ALCL and a positive correlation between apoptotic index and Ki67 index (p<0.001) was detected. Ki67, cyclin A and cyclin B1 expression was found in all 57 TCL and on the basis of the combined use of these 3 variables, 3 groups of proliferative activity could be determined: a) high in ALCL and T-LBL, b) low in mycosis fungoides (MF) and gammadelta hepatosplenic TCL, and c) intermediate in the remaining TCL entities. The proliferative activity in the 12 p53 overexpressing cases was higher in comparison to the 45 p53-negative cases. Ki67 expresion in more than 25% of tumour cells showed significant correlation with p53 overexpression (p<0.001). Rb expression tended to be parallel to Ki67, cyclin A and cyclin B1 expression in all but one case of nodal PTCL-UC which displayed loss of RB expression. Interestingly, this case was p53-negative, whereas the p53-positive cases were Rb-positive. These findings suggest that different pathogenetic routes may function in some TCL, involving either the p53 or, less frequently, the Rb pathways.

Extranodal cytotoxic T-cell lymphoma in a patient with X-linked agammaglobulinaemia.

This report documents the occurrence of an extranodal cytotoxic peripheral T-cell lymphoma (PTCL) in a patient with X-linked agammaglobulinaemia (XLA). The diagnosis was based on the immunohistochemical detection of T-cell antigens and of the cytotoxic proteins TIA1 and Granzyme B in the tumour cells. This report provides further evidence that cytotoxic lymphomas are part of the differential diagnosis of neoplasia in patients with immunodeficiencies.

Immunohistochemical expression of the p53, p21/Waf-1, Rb, p16 and Ki67 proteins in multiple myeloma.

The aim of this study was to investigate the immunohistochemical expression of the proteins p53, Waf-l/p21, Rb, p16 and Ki67 in 38 cases of multiple myelomas (MM) and 4 cases of solitary extramedullary plasmacytomas in relation to the tumor histological grade and stage. In bone marrow (BM) biopsies from MM, overexpression of p53 and p21 proteins, in comparison to plasma cell infiltrates in non-pathological bone marrow, was detected in 13 out of 38 and 21 out of 38 cases, respectively. The combined immunoexpression of p53 and p21 proteins in the 38 cases of MM showed the following patterns: a) p53+/p21+ (13 cases) b) p53-/p21+ (8 cases) and c) p53-/p21- (17 cases). Rb, p16 and Ki67 proteins were detected in tumor cells in all 38 cases and their expression increased proportionally to tumor grade. The 4 cases of solitary extramedullary plasmacytomas showed the p53+/p21+ pattern in 2 cases and the p53-/p21+ pattern in 2 cases, all of them displaying Rb, p16 and Ki67 expression in tumor cells. The pattern p53+/p21+ might represent cases with wild-type p53 able to induce p21 expression. However, in previous studies p53 mutations were reported in about 3-10% of MM, and they were strongly associated with advanced disease. Thus, in some p53+/p21+ cases associated with high p53 expression and advanced disease, p53 gene cannot be excluded and up-regulation of p21 expression may be p53- independent. P53 overexpression correlated with increased tumor grade (p < 0.005), advanced histological stage (p < 0.001) and Ki67 expression in more than 10% of tumor cells (p < 0.001). Since increase in Ki67 expression also correlated with increased tumor grade (p < 0.001) and advanced histological stage (p < 0.001), these findings suggest that impairment of the p53 growth control pathway is associated with tumor progression in MM. Thus, p53 and Ki67 immunostaining in routine BM biopsies may be helpful for the detection of MM with potentially aggressive behavior. Overexpression of p21 in MM correlated with higher Ki67 expression (p < 0.005), suggesting that the p21 function of arresting cell-cycle is impaired. Ki-67 expression in MM increased in parallel with p16 (p < 0.001) and Rb expression (p < 0.001). Rb expression could represent a growth control response which, however, might not be able to induce growth arrest in view of the parallel increase in Ki67 expression and of previous findings showing that Rb protein in MM cells is expressed mostly in its phosphorylated form.

Cytotoxic protein expression in non-Hodgkin's lymphomas and Hodgkin's disease.

Recent studies have shown that some peripheral T-cell lymphomas (PTCL) could be derived from lymphocytes with cytotoxic potential. Therefore, we have investigated by immunohistochemistry 34 cases of PTCL including 2 cases of hepatosplenic gamma delta PTCL and 5 cases of sinonasal NK-cell lymphomas as well as 7 cases of T-lymphoblastic lymphomas (T-LBL) for the expression of the cytotoxic proteins TIA-1 and granzyme B. In addition, 50 cases of Hodgkin's disease (HD) were investigated in order to see if these cytotoxic proteins are expressed by Hodgkin and Reed-Sternberg (HRS) cells. Expression of the TIA-1 is characteristic of cytotoxic cells regardless of their activation status whereas expression of granzymes is highly increased in activated cytotoxic cells. All the five cases of sinonasal NK-cell lymphomas expressed TIA-1 and granzyme B in most tumour cells. The two gamma delta PTCL cases expressed TIA-1 protein in most tumour cells but not granzyme B. Of the 32 other PTCL, 9 cases showed cytotoxic protein expression in tumour cells. These cases comprised 2 pleomorphic medium large cell (PML) (1 nodal and 1 intestinal) and 7 CD30 positive anaplastic large cell lymphomas (ALCL) (5 nodal and 2 cutaneous). Cytotoxic protein expression in our series appeared to be related to the location since 10/18 (55%) extranodal PTCL and NK-NHL and only 6/21 (28%) nodal PTCL expressed TIA-1, and related to histology since, in nodal PTCL, this pattern was observed in most anaplastic (5/6 cases) and in a few pleomorphic (1/9 cases) lymphomas, but not in AILD-type NHL (0/6 cases). The 7 cases of T-LBL did not express cytotoxic proteins in tumour cells. EBV was detected by EBER RNA in situ hybridization (RISH) in tumour cells in all 5 sinonasal NK-NHL and in scattered atypical cells in all 6 cases of AILD. Two of the 50 cases of HD weakly expressed TIA-1 and granzyme B in a proportion of HRS cells. EBV was detected by RISH in 19/50 cases of HD but no correlation was found between EBV status and expression of cytotoxic proteins in HRS cells. However, the finding that granzyme B positive cells were found very rarely in close vicinity of HRS cells suggests that the function of activated cytotoxic cells is locally inhibited by the HRS cells and/or the reactive cells in the vicinity of HRS cells. Taken together our data suggest that: a) sinonasal NK-cell NHL represent tumours of activated cytotoxic NK-cells, b) the hepatosplenic gamma delta PTCL represent tumours of nonactivated cytotoxic gamma delta T-cells, c) a small proportion of other PTCL, mostly anaplastic large cell lymphomas represent tumours of cytotoxic T-cells and d) only very few cases of HD expressing cytotoxic proteins in a proportion of tumour cells, could be derived from activated cytotoxic cells.

Expression of p53, p21, mdm2, Rb, bax and Ki67 proteins in lymphomas of the mucosa-associated lymphoid (MALT) tissue.

We have investigated by immunohistochemistry 38 cases of B-cell MALT-NHL comprising 23 high grade (HG) and 15 low grade-(LG) tumours for the expression of p53, mdm2, p21, Rb, Ki67, bcl2 and Bax proteins. P53, mdm2 and p21 proteins were found in at least 5% of the tumour cells in 13/23, 2/23 and 11/23 HG tumours, respectively. These proteins were detected in very rare tumour cells in LG tumours. The following patterns were recorded in HG tumours: p53+/p21+/mdm2+ (2 cases), p53+/p21+/mdm2- (7 cases), p53+/p21-/mdm2- (4 cases), p53-/p21-/mdm2- (18 cases) and p53-/p21+/mdm2-(2 cases). Proliferative Ki67 index and Rb protein expression were higher in HG than in LG MALT-NHL. Bcl2 protein was expressed in all LG MALT-NHL, whereas only 2/23 HG MALT-NHL were bcl2 positive in most tumour cells. Bax protein was expressed in all MALT-NHL with HG tumours being positive in higher proportion of tumour cells than LG tumours. These findings show that significant expression of p53, mdm2, p21,Ki67 and Rb proteins occurs more frequently in aggressive histotypes of MALT-NHL. The parallel Rb/Ki67 expression suggests that Rb protein expression in MALT-NHL is normally regulated in relation to the proliferative growth fraction of the tumours. The pattern p53+/p21+/mdm2 +/- may represent MALT-NHL with wild type (wt) p53 gene since mdm2 and p21 proteins are inducible by wt p53 gene. The pattern p53+/mdm2-/p21-may represent MALT-NHL with p53 gene mutations unable to activate expression of mdm2 and p21 proteins. MALT-NHL with the p53-/mdm2-/p21 + pattern may be consistent with p53-independent p21 expression. Bax protein expression in all MALT-NHL suggests a role for this protein in the pathogenesis of these tumours.

Major histocompatibility complex (MHC)-I and MHC-II expression in Hodgkin's disease in relation to the presence of Epstein-Barr Virus (EBV).

We have investigated the immunohistochemical expression of beta2-microglobulin and HLA-DR proteins in Hodgkin's disease (HD) in relation to the expression of the EBV-encoded EBER1-2 mRNAs and the LMP-1 protein. beta2-microglobulin is expressed in association with MHC-I molecules on most nucleated cells and HLA-DR belongs to the MHC-II molecules which are expressed mostly on antigen-presenting cells. Formalin-fixed paraffin embedded tissue from 39 cases of lymphonodal HD were stained by immunohistochemistry for beta2-microglobulin, HLA-DR and LMP-1 proteins and by RNA in situ hybridization for EBER1-2 mRNAs. beta2-microglobulin positive staining was found in Reed-Sternberg and Hodgkin cells (HRS cells) in 18/39 cases of HD. HLA-DR positive staining was found in HRS cells in all cases of HD. EBER1-2 transcripts and LMP-1 protein were detected in HRS cells in 16/39 cases of HD. No correlation as found between the presence of EBER 1-2 transcripts or the LMP-1 protein and the detection of beta2-microglobulin and HLA-DR proteins in HD. Thus, EBV does not seem to use downregulation of MHC-I to avoid the T-cell cytotoxic immune response in HD. In addition, EBV does not seem to be the only factor responsible for the HLA-DR expression in HRS cells of HD, although it could participate in the induction of the expression of HLA-DR molecule in the EBV positive cases of HD.

MIB1 (Ki-67) expression in non-Hodgkin's lymphomas.

The MIB1 monoclonal antibody which is used as a marker of cell proliferation was studied by immunohistochemistry on formalin-fixed and paraffin embedded biopsy specimens of lymph nodes in 40 high- and 46 lowgrade cases of non-Hodgkin's lymphomas (NHL) classified according to the Kiel classification. All cases were found to display nuclear MIB1 staining. A statistically significant difference (P < 0.005) was found between high- and low grade NHLs and this indicates that the high- grade NHL display a higher proliferation rate than low grade. In addition, remarkable variations in MIB1 expression were found among individual cases of the same histological group. These data may suggest that MIB1 index can help in the individual approach of the proliferation rate of each tumour and this may be an important parameter in association with clinical and other laboratory parameters for predicting the biological behaviour of non-Hodgkin's lymphomas.

P21/waf1 protein expression in nasopharyngeal carcinoma. Comparative study with PCNA, p53 and MDM-2 protein expression.

We investigated the immunohistochemical expression of p21/waf1 protein in 59 cases of nasopharyngeal carcinomas (NPC) and compared p21 expression with PCNA, p53 and mdm2 protein expression. We found p21, PCNA, p53 and mdm2 in 59/59, 59/59, 18/59 and 12/59 nasopharyngeal carcinomas, respectively. We observed a tendency to a relationship between high expression of PCNA (> 25% positivity in tumour cells) and low expression of p21 protein. Parallel p53/p21 protein expression was found in 18 cases. Twelve were also mdm2 positive. This pattern may represent NPC with wild type (wt) p53 since mdm2 and p21 proteins are inducible by wt p53 gene. In these cases p53 protein expression may be due to stabilisation to mdm2 protein. This could be important in the pathogenesis of these cases since mdm2 may deregulate the p53-dependent growth suppressive pathway. Discordant p53-/p21+ protein expression was found in 41 cases. All were also mdm2 negative. This pattern suggests immunohistochemically undetectable wt p53 gene which is able to induce p21 protein expression.

Expression of p53 and mdm-2 proteins in Hodgkin's Disease. Absence of correlation with the presence of Epstein-Barr virus.

The expression of p53 and mdm-2 proteins was analysed in parrafin sections from 39 cases of Hodgkin's disease (HD) and compared to the presence of Epstein-Barr Virus (EBV). P53 protein was found in Hodgkin and Reed-Sternberg (HRS) cells in 12/39 cases. Mdm-2 protein was found in HRS cells in 10/39 cases. EBV-encoded EBER1-2 mRNAs and LMP-1 protein expression were found in HRS cells in 16/39 cases. In view of the LMP-1 oncogenic potential in vitro, these findings suggest that EBV may be involved in the pathogenesis of a proportion of HD cases. The coexpression of mdm-2 and p53 proteins was found in HRS cells in 10 cases, whereas in 27 cases neither was identified and in 2 cases there was no coexpression of mdm-2/p53. The simultaneous p53/mdm-2 protein expression, in view of previous findings which showed that most cases of HD display no p53 gene mutations, suggests that mdm-2 protein expression may be one of the factors responsible for the stabilisation of p53 protein in these cases. This could be important, in the pathogenesis of these cases of HD, since mdm-2 may deregulate the p53 dependent growth suppressive pathway. Mdm-2-/ p53+ protein expression may reflect the stabilisation of p53 protein by proteins other than mdm-2, mutations in the p53 gene making it unable to activate mdm-2, or the deregulation of the mdm-2 gene. No relationship was found between the presence of EBV and the expression of p53 and/or mdm-2 proteins.

Multiple cervical and intrathoracic plexoid neurofibromas. Case report.

A 29-year-old male with known von Recklinghausen's disease is presented. The main symptom of the patient was paroxysmal episodes of pain and numbness in the right upper hand for the last 10 years. Cervical and mediastial magnetic resonance imaging (MRI) revealed 3 large tumors originating from the right vagus nerve and another of the same origin contralaterally. Surgical resection of the masses in the right hemithorax was performed via right posterolateral thoracotomy. The postoperative course was uneventful and symptoms recessed. Plexoid neurofibromas were diagnosed at histological examination. The mass in the left hemithorax is under surveillance according to the patient's preference. The clinical, radiological, surgical, and histopathological features of this rare case are discussed.