Are myoepithelial cells responsible for the widespread expression of inducible nitric oxide synthase in pleomorphic adenoma? An immunohistochemical study

Unlocking immunotherapy targets: programmed death 1 and its ligand and their correlation with tumour grade in feline injection site sarcoma

In this study, the immunohistochemical expression of programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1), which could facilitate a novel approach to immunotherapy for feline injection site sarcomas (FISSs), was investigated. Treatment strategies based on the suppression of this pathway are possible for tumours expressing PD-1/PD-L1. In this context, FISSs were histologically classified, the grade of sarcoma and the intensity of lymphocyte infiltration determined and PD-1 and PD-L1 expression evaluated in tumours of different grade. Tumours were immunolabelled for vimentin, S100, smooth muscle actin and sarcomeric actin. Fibrosarcoma was diagnosed in eight cases, undifferentiated sarcoma in one case, liposarcoma in one case and rhabdomyosarcoma in one case. PD-1 expression was found mainly in lymphoid infiltrations and macrophage-like cells, while PD-L1 was found primarily in tumour cells and infiltrated macrophage-like cells. By Pearson correlation analysis, tumour differentiation was found to have a moderate correlation with PD-1 (P <0.05) and a high correlation with PD-L1 (P <0.01). Tumour grade had a low correlation with PD-1 and a moderate correlation with PD-L1 (P >0.05). A moderate correlation was also detected between PD-1 and PD-L1 (P <0.05). It was concluded that the increased expression of PD-1 and PD-L1 may be associated with poor tumour differentiation and, therefore, poor prognosis in FISS.

Histological and Immunohistochemical Analysis of Peri-Implant Soft and Hard Tissues in Patients with Peri-Implantitis

Currently, researchers are focused on the study of cytokines as predictive biomarkers of peri-implantitis (PI) in order to obtain an early diagnosis and prognosis, and for treatment of the disease. The aim of the study was to characterize the peri-implant soft and hard tissues in patients with a peri-implantitis diagnosis. A descriptive observational study was conducted. Fifteen soft tissue (ST) samples and six peri-implant bone tissue (BT) samples were obtained from 13 patients who were diagnosed with peri-implantitis. All the samples were processed and embedded in paraffin for histological and immunohistochemical analyses. A descriptive and quantitative analysis of mast cells and osteocytes, A proliferation-inducing ligand (APRIL), B-cell activating factor (BAFF), osteonectin (ON), and ∝-smooth muscle actin (∝-SMA) was performed. We observed the presence of mast cells in peri-implant soft tissue in all samples (mean 9.21 number of mast cells) and osteocytes in peri-implant hard tissue in all samples (mean 37.17 number of osteocytes). The expression of APRIL-ST was 32.17% ± 6.39%, and that of APRIL-BT was 7.09% ± 5.94%. The BAFF-ST expression was 17.26 ± 12.90%, and the BAFF-BT was 12.16% ± 6.30%. The mean percentage of ON was 7.93% ± 3.79%, and ∝-SMA was 1.78% ± 3.79%. It was concluded that the expression of APRIL and BAFF suggests their involvement in the bone resorption observed in peri-implantitis. The lower expression of osteonectin in the peri-implant bone tissue can also be associated with a deficiency in the regulation of bone remodeling and the consequent peri-implant bone loss.

Rho-kinase expression in Hirschsprung's disease

BACKGROUND

Rho-kinase (ROCK) is the primary effector protein in the RhoA pathway, which regulates Ca(2+)-independent smooth muscle contraction in the human bowel. This pathway has been reported to be hyper-activated in the aganglionic bowel of EDNRB-null (-/-) rats compared to the ganglionic bowel from EDNRB (+/+) rats. We hypothesised that ROCK expression is up-regulated in human aganglionic bowel and designed this study to investigate ROCK 1 and ROCK 2 expression in Hirschsprung's disease (HSCR) and controls.

MATERIALS AND METHODS

Full-length specimens were collected following pull-through surgery for HSCR (n = 9). Colonic controls (n = 6) were obtained during colostomy closure from patients with anorectal malformations. Distribution of ROCK 1/2 expression was evaluated using double-labelled immunofluorescence and confocal microscopy. ROCK1/2 protein expression was assessed in mucosa and tunica muscularis using western blot analysis.

RESULTS

There was strong expression of both ROCK 1 and ROCK 2 in interstitial cells of Cajal (ICCs) and ganglia. ROCK 1 expression was reduced in aganglionic bowel compared to HSCR ganglionic bowel and controls in both mucosa and tunica muscularis. ROCK 2 expression was similar in the colon of children with HSCR and controls.

CONCLUSIONS

This is the first report of strong ROCK expression in colonic ICCs. Although the rat model of aganglionic bowel suggests that Ca(2+)-independent smooth muscle contraction involving ROCK is hyper-activated, our data indicate ROCK 1 expression is decreased in aganglionic bowel and ROCK 2 expression is unaltered in children with HSCR.

Nitric oxide synthase 2 (NOS2) expression in histologically normal margins of oral squamous cell carcinoma

The activity of Nitric Oxide Synthase 2 (NOS2) was found in oral squamous cell carcinomas (OSCC) but not in normal mucosa. Molecular changes associated to early carcinogenesis have been found in mucosa near carcinomas, which is considered a model to study field cancerization. The aim of the present study is to analyze NOS2 expression at the histologically normal margins of OSCC.

STUDY DESIGN

Eleven biopsy specimens of OSCC containing histologically normal margins (HNM) were analyzed. Ten biopsies of normal oral mucosa were used as controls. The activity of NOS2 was determined by immunohistochemistry. Salivary nitrate and nitrite as well as tobacco and alcohol consumption were also analyzed. The Chi-squared test was applied.

RESULTS

Six out of the eleven HNM from carcinoma samples showed positive NOS2 activity whereas all the control group samples yielded negative (p=0.005). No statistically significant association between enzyme expression and tobacco and/or alcohol consumption and salivary nitrate and nitrite was found.

CONCLUSION

NOS2 expression would be an additional evidence of alterations that may occur in a state of field cancerization before the appearance of potentially malignant morphological changes.

Tumours of the lacrimal gland. Epidemiological, clinical and genetic characteristics

Tumours of the lacrimal gland are rare, but the prognosis may be grave. To date, no population-based incidence and distribution data on lacrimal gland tumours exist. In addition, almost nothing is known about the genetic profile of epithelial tumours of the lacrimal gland. We collected specimens and clinical files on all biopsied lacrimal gland lesions in Denmark over a 34-year period and re-evaluated the diagnosis to provide updated population-based incidence rates and epidemiological characteristics. Clinical data regarding symptoms, clinical examinations, treatment and follow-up were collected for patients with adenoid cystic carcinoma (ACC), pleomorphic adenoma (PA), carcinoma ex pleomorphic adenoma (Ca-ex-PA) and mucoepidermoid carcinoma (MEC). Using RT-PCR, FISH, immunohistochemistry, Q-PCR and high-resolution array-based comparative genomic hybridization (arrayCGH) we explored the genetic characteristics including copy number alterations (CNA) in ACC, PA, Ca-ex-PA and MEC. The incidence of biopsied lacrimal gland lesions was 1.3/1,000,000/year, and ~50% were neoplastic lesions. Of these, 55% were malignant tumours with epithelial tumours as the most frequent. The overall incidence was increasing, and this was caused by an increase in biopsied non-neoplastic lesions. We found that 10/14 ACCs either expressed the MYB-NFIB fusion gene and/or had rearrangements of MYB. All ACCs expressed the MYB protein. ACC was characterized by recurrent copy number losses involving 6q, 12q and 17q and gains involving 19q, 8q and 11q. ArrayCGH revealed an apparently normal genomic profile in 11/19 PAs. The remaining 8 PAs had recurrent copy number losses involving 1p, 6q, 8q and 13q and gain involving 9p. PA expressed PLAG1 in all tumours whereas only 2/29 tumours expressed HMGA2. Ca-ex-PA was characterized by recurrent copy number gain involving 22q. PLAG1 was expressed in 3/5 Ca-ex-PA whereas none of these tumours expressed HMGA2. MEC expressed the CRTC1-MAML2, and this fusion was found to be tumour-specific for lacrimal gland MEC. In conclusion, lacrimal gland lesions that require pathological evaluation are rare in the Danish population, and the incidence rate of biopsied benign lesions is increasing. Epithelial tumours of the lacrimal gland are molecularly very similar to their salivary gland counterparts in the expression of the tumour-specific fusion genes and in their genomic imbalances as demonstrated by arrayCGH. MYB-NFIB is a useful biomarker for ACC and MYB, and its downstream target genes may be potential therapeutic targets for these tumours.

Antibody selection for immunocytochemical characterization of the male reproductive system in Psittaciformes

The success of breeding programs is limited by the sparse knowledge about endocrine regulation and biochemical reactions in the psittacine male tract. The immunocytochemical analysis of parrots' testicular tissues provides an insight into their reproductive system but is often hampered by the lack of reliable antibodies. In the present study, we tested a large panel of antibodies raised against steroid receptors, steroidogenic enzymes, relaxin peptides including their receptors, and proliferation markers on paraffin sections of testicular tissue from eight psittacine genera representing three continents. All investigated species displayed the tested markers in somatic and germ cells of testis and epididymis, even though cell distribution was partly heterogenous and in species-specific patterns. The 17β-hydroxysteroid-dehydrogenase-2, 3β-hydroxysteroid-dehydrogenase, and smooth muscle actin allowed the cross-species differentiation between active and nonactive gonads. The remaining steroidogenic enzymes, steroid receptors, relaxin peptides, and Ki67 proved to be suitable to define reproductive activity depending on the parrot species. Adapting immunocytochemical methods to different psittacines was successful, though various cellular expression patterns do not allow the transfer of results among different parrot species. However, the availability of a reliable repertory of sexual markers is important to examine reproductive biology of psittacine birds.

iNOS expression in oral and gastrointestinal tract mucosa

It is known that the overproduction of nitric oxide (NO) by nitric oxide synthase (NOS) occurs during the progression of various inflammatory diseases in intestinal tract. NOS inhibitors or inducible nitric oxide synthase (iNOS) gene expression inhibitors should be considered as potential anti-inflammatory agents, as NO synthesized by iNOS is related to various pathophysiological processes including inflammation. In order to understand the relationship between iNOS and pathological reactions such as the inflammatory process and malign transformation clearly, the existence and amount of constitutive expression should be determined. It is crucial to comprehend the harmful and protective amounts of iNOS expressions in order to clarify the relationship between iNOS and pathological processes. Evidently, only after this inspection is it possible to utilize iNOS as a marker and treatment instrument during the diagnosis and treatment of malign transformation and the inflammatory process.

Expressions of nuclear factor kappaB, inducible nitric oxide synthase, and vascular endothelial growth factor in adenoid cystic carcinoma of salivary glands: correlations with the angiogenesis and clinical outcome

OBJECTIVE

To evaluate the expressions of nuclear factor kappaB (NF-kappaB p65), inducible nitric oxide synthase enzyme (iNOS), and vascular endothelial growth factor (VEGF) in relation to angiogenesis (microvessel density, MVD) and clinical outcomes in adenoid cystic carcinoma (ACC) of salivary glands.

METHODS

Immunohistochemical staining was used to quantify the protein expression levels of NF-kappaB p65, iNOS, and VEGF in 80 surgically resected ACCs and 20 normal salivary tissues. In all cases of ACCs, MVD was evaluated by counting CD34-reactive endothelial cells or endothelial cell clusters.

RESULTS

The nuclear localization of NF-kappaB p65 was only detected in ACC cells. Both iNOS and VEGF staining activities in ACCs were more significant than those in normal gland tissues (P < 0.01). MVD had significant correlations with NF-kappaB p65, iNOS, and VEGF expressions (P < 0.01). In three histologic types of ACCs, the NF-kappaB, iNOS, VEGF expressions, and MVD were significantly higher in solid type than in cribriform and tubular types (P < 0.01). The NF-kappaB, iNOS, VEGF expressions, and MVD were significantly correlated with clinical stage, tumor size, vascular invasion, recurrence, and metastasis (P < 0.05). Multivariate analysis showed NF-kappaB, iNOS and VEGF expression, MVD, solid histotype, and perineural invasion had an independent prognostic effect on overall survival.

CONCLUSION

The expressions of NF-kappaB p65, iNOS, and VEGF were related with MVD. Clinical outcomes raised the possibility that the overexpression of these cytokines might contribute to tumor angiogenesis and have prognostic value in ACCs.

The role of nitric oxide in oral diseases

Although previously regarded as a toxic pollutant gas, nitric oxide (NO) is a short-lived molecule that plays a key role in many physiological and pathological processes. It is produced in vivo from the amino acid L-arginine by a complex family of enzymes termed nitric oxide synthase (NOS). Since its discovery as a biological messenger in 1987, NO has been implicated in many disease processes, ranging from septic shock to cancer. It is a highly reactive free radical and causes concentration-dependent conformational changes in proteins, enzymes and DNA, predominantly by its reaction with transition metals and thiol residues. Although high concentrations of NO are cytotoxic, the levels produced in many human cancers possibly facilitate tumour growth and dissemination. The interest in this molecule by scientists and clinicians involved with the oral cavity and head and neck regions is fairly recent, and only a tiny minority of 50,000 papers currently cited on NO relate to diseases in this anatomical area. This review gives an overview of NO, outlining its basic chemistry, formation by NOS and its possible roles in the oral diseases studied to date. The implications for possible therapeutic manipulation of NO are also discussed.

Expression of type 2 nitric oxide synthase and vascular endothelial growth factor in oral dysplasia

PURPOSE

The small molecule nitric oxide (NO), produced by a family of enzymes called NO synthase (NOS), has a diverse array of functions in both physiologic and pathologic states. Prolonged production of NO by the isoform NOS2 has been implicated in human cancer progression. NO has an important role in angiogenesis, being both an upstream signal and a downstream effector molecule to vascular endothelial growth factor (VEGF). The latter group of proteins are crucial for vascular endothelial cell proliferation and permeability. The expression of VEGF increases with cancer progression. Because angiogenesis is a prerequisite for the development of invasive cancer, this immunohistochemical study investigated the expression of NOS2 and VEGF in oral epithelial dysplasia.

MATERIALS AND METHODS

An immunohistochemical study was performed using monoclonal antibodies to NOS2 and VEGF on archival formalin-fixed, paraffin-embedded tissue of 33 cases of oral dysplasia.

RESULTS

A significant correlation was found between NOS2 and VEGF expression in oral dysplasia (P <.001). Expression of both NOS2 and VEGF also correlated with the severity of dysplasia (P <.001, P <.002).

CONCLUSIONS

These findings may provide further understanding to the complex transformation of oral epithelial dysplasia to invasive carcinoma and the role of angiogenesis in this process.

Immunohistochemical analysis of inducible nitric oxide synthase (iNOS) and heat shock proteins (HSPs) in ameloblastomas

BACKGROUND

To clarify the possible role of nitric oxide (NO) and stress proteins in oncogenesis and cytodifferentiation of odontogenic epithelium. Inducible NO synthase (iNOS) and heat shock proteins (HSPs) were analyzed in ameloblastomas as well as in tooth germs.

METHODS

Specimens of seven tooth germs, 36 benign ameloblastomas and five malignant ameloblastomas were examined by immunohistochemistry using antibodies against iNOS and 27-, 60- and 70-kDa HSPs (HSP27, HSP60 and HSP70).

RESULTS

Immunoreactivity for iNOS was detected in normal and neoplastic odontogenic epithelial cells and was higher in malignant ameloblastomas than in tooth germs and benign ameloblastomas. HSP27 was expressed constitutively in all odontogenic epithelial cells in tooth germs and benign and malignant ameloblastomas. Expression of HSP60 and HSP70 was detected in normal and neoplastic odontogenic epithelial cells and was prominent in cells neighboring the basement membrane. HSP60 reactivity showed no apparent difference between normal and neoplastic odontogenic epithelium, whereas HSP70 expression was slightly higher in benign and malignant ameloblastomas than in tooth germs.

CONCLUSIONS

Activation of iNOS might be associated with malignant potential of epithelial odontogenic tumors. Elevated expression of HSP70 is considered to be involved in neoplastic transformation of odontogenic epithelial cells.

Expression of type 2 nitric oxide synthase and p53 in Warthin's tumour of the parotid

Although the pathogenesis of Warthin's tumour is not fully understood, it is generally thought that the tumour arises from heterotopic salivary ducts within pre-existing lymphoid tissue. Prolonged nitric oxide (NO) production by the enzyme type 2 nitric oxide synthase (NOS2) has been implicated in the pathogenesis of many solid tumours, but not in Warthin's tumour. Since NO and NOS2 are known to be associated with p53, the immunohistochemical expression of both NOS2 and p53 was investigated in 23 cases of Warthin's tumour. Widespread diffuse cytoplasmic immunostaining for NOS2 was found in tumour epithelial cells of all 23 cases studied, and it was additionally expressed in normal salivary duct epithelium. p53 staining was localised to the nuclei of tumour epithelium in 16 cases, with a similar pattern of distribution to tumour NOS2 expression. A significant correlation was found between NOS2 and p53 staining in the tumours (P < 0.001). In contrast to NOS2, p53 was not expressed by normal salivary ductal cells in any of the cases studied. NOS2 is widely expressed by the tumour epithelium of Warthin's, and its association with p53 expression is discussed. The role of NO in the pathogenesis of Warthin's tumour remains to be established.

Expression of inducible nitric oxide synthase and heat shock proteins in periapical inflammatory lesions

BACKGROUND

The mechanisms responsible for activation and proliferation of lining epithelium involved in inflammatory processes in periapical inflammatory lesions remain unclear. In this study, the expression and distribution of inducible nitric oxide synthase (iNOS) and heat shock proteins (HSPs) were immunohistochemically investigated in periapical inflammatory lesions.

METHODS

Control specimens of periodontal ligaments including Malassez epithelial rests from seven teeth and periapical inflammatory lesions (15 apical granulomas (AGs), 16 radicular cysts (RCs), and 10 residual radicular cysts (RRCs)) were prepared and examined by the standard streptavidin-biotin peroxidase complex method using anti-iNOS rabbit polyclonal antiserum, and anti-HSP27, -HSP60, -HSP70 mouse monoclonal antibodies.

RESULTS

Immunoreactivity for iNOS was detected in macrophages, lymphocytes, and endothelial cells of granulation tissue and in lining epithelium of periapical inflammatory lesions. Malassez epithelial rests showed no or slight staining for iNOS. The epithelial staining intensity of iNOS in RCs was greater than that in Malassez epithelial rests and RRCs. Immunoreactivity for HSP27 was recognized in inflammatory cells, endothelial cells and lining epithelium of periapical inflammatory lesions and in Malassez epithelial rests. HSP60 was detected in some lymphocytes of granulation tissue and in lining epithelium of periapical inflammatory lesions, whereas Malassez epithelial rests showed no staining for HSP60. Epithelial HSP60 reactivity was more intense in RCs than in RRCs. HSP70 was expressed in lymphocytes, endothelial cells and lining epithelium of periapical inflammatory lesions and in Malassez epithelial rests. The staining intensity of HSP70 in Malassez epithelial rests was slightly lower than that in lining epithelium of RCs and RRCs.

CONCLUSIONS

These data demonstrate that the expressions of iNOS, HSP60, and HSP70 are involved in inflammatory processes and might play a role in the activation and proliferation of lining epithelium, leading to progression of periapical inflammatory lesions.

Expression of type 2 nitric oxide synthase and p21 in oral squamous cell carcinoma

Nitric oxide (NO) has a complex role in tumour biology. Most cancer research has focused on the enzyme nitric oxide synthase-2 (NOS2), an inducible isoform responsible for prolonged NO production. In normal cells exposed to high NO concentrations, the tumour-suppressor gene, p53, promotes apoptosis via the p21 pathway, in an attempt to safeguard against potential NO-mediated DNA damage. In cancer cells with mutant p53, this pathway is unlikely to occur directly, although, p53-independent p21 expression and subsequent apoptosis can occur at higher NO concentrations. In this study, the possible direct association between NOS2 and p21 was assessed in oral squamous cell carcinoma. Immunohistochemistry was performed for NOS2 and p21 on 56 cases, and NOS2 activity was determined with citrulline assays in selected cases. A significant relationship was demonstrated between the immunohistochemical expression of NOS2 and its activity (P<0.001), but not between NOS2 and p21 expression (P=0.76). It is unlikely that the NO concentrations found in oral cancer (up to 10.3 pmol NO min(-1) mg protein(-1)) are sufficient to cause direct (p53-independent) p21 accumulation and subsequent apoptosis. As with many other tumours, since NO production has a detrimental role, its pharmacological inhibition in oral cancer represents an exciting area for possible future therapeutic manipulation.