Expression of a cell-cycle-associated nuclear antigen (MIB 1) in cholesteatoma and auditory meatal skin

Morphopathogenesis of Adult Acquired Cholesteatoma

Background and Objectives. The aim of this study was to compare the distribution of proliferation markers (Ki-67, NF-κβ), tissue-remodeling factors (MMP-2, MMP-9, TIMP-2, TIMP-4), vascular endothelial growth factor (VEGF), interleukins (IL-1 and IL-10), human beta defensins (HβD-2 and HβD-4) and Sonic hedgehog gene protein in cholesteatoma and control skin. Methods. Nineteen patient cholesteatoma tissues and seven control skin materials from cadavers were included in the study and stained immunohistochemically. Results. Statistically discernible differences were found between the following: the Ki-67 in the matrix and the Ki-67 in the skin epithelium (p = 0.000); the Ki-67 in the perimatrix and the Ki-67 in the connective tissue (p = 0.010); the NF-κβ in the cholesteatoma matrix and the NF-κβ in the epithelium (p = 0.001); the MMP-9 in the matrix and the MMP-9 in the epithelium (p = 0.008); the HβD-2 in the perimatrix and the HβD-2 in the connective tissue (p = 0.004); and the Shh in the cholesteatoma's perimatrix and the Shh in the skin's connective tissue (p = 0.000). Conclusion. The elevation of Ki-67 and NF-κβ suggests the induction of cellular proliferation in the cholesteatoma. Intercorrelations between VEGF, NF-κβ and TIMP-2 induce neo-angiogenesis in adult cholesteatoma. The similarity in the expression of IL-1 and IL-10 suggests the dysregulation of the local immune status in cholesteatoma. The overexpression of the Sonic hedgehog gene protein in the cholesteatoma proves the selective local stimulation of perimatrix development.

Chronic inflammation of middle ear cholesteatoma promotes its recurrence via a paracrine mechanism

Background

Cholesteatoma disease is an expanding lesion in the middle ear. Hearing loss and facial paralysis alongside with other intracranial complications are found. No pharmaceutical treatment is available today and recurrence after surgical extraction occurs. We investigated possible TLR4-based mechanisms promoting recurrence and explore possible treatments strategies.

Methods

We isolated fibroblasts and epidermal stem cells from cholesteatoma tissue and healthy auditory canal skin. Subsequently, their expression under standard culture conditions and after stimulation with LPS was investigated by RT-qPCR. Cell metabolism and proliferation were analysed upon LPS treatment, with and without TLR4 antagonist. An indirect co-culture of fibroblasts and epidermal stem cells isolated from cholesteatoma tissue was utilized to monitor epidermal differentiation upon LPS treatment by RT-qPCR and immunocytochemistry.

Results

Under standard culture conditions, we detected a tissue-independent higher expression of IL-1β and IL-8 in stem cells, an upregulation of KGF and IGF-2 in both cell types derived from cholesteatoma and higher expression of TLR4 in stem cells derived from cholesteatoma tissue. Upon LPS challenge, we could detect a significantly higher expression of IL-1α, IL-1β, IL-6 and IL-8 in stem cells and of TNF-a, GM-CSF and CXCL-5 in stem cells and fibroblasts derived from cholesteatoma. The expression of the growth factors KGF, EGF, EREG, IGF-2 and HGF was significantly higher in fibroblasts, particularly when derived from cholesteatoma. Upon treatment with LPS the metabolism was elevated in stem cells and fibroblasts, proliferation was only enhanced in fibroblasts derived from cholesteatoma. This could be reversed by the treatment with a TLR4 antagonist. The cholesteatoma fibroblasts could be triggered by LPS to promote the epidermal differentiation of the stem cells, while no LPS treatment or LPS treatment without the presence of fibroblasts did not result in such a differentiation.

Conclusion

We propose that cholesteatoma recurrence is based on TLR4 signalling imprinted in the cholesteatoma cells. It induces excessive inflammation of stem cells and fibroblasts, proliferation of perimatrix fibroblasts and the generation of epidermal cells from stem cells thru paracrine signalling by fibroblasts. Treatment of the operation site with a TLR4 antagonist might reduce the chance of cholesteatoma recurrence.

Down-regulation of exosomal miR-106b-5p derived from cholesteatoma perimatrix fibroblasts promotes angiogenesis in endothelial cells by overexpression of Angiopoietin 2

Human cholesteatoma perimatrix fibroblasts (hCPFs) can stimulate the endothelial cells of nearby microvessels to proliferate and migrate in a paracrine manner. Exosomes, secreted from various cell types, are one of the most important paracrine factors and play critical roles in intercellular communication. However, whether exosomes derived from human cholesteatoma perimatrix fibroblasts (hCPFs-Exo) can promote angiogenesis has not been reported. In this study, we isolated exosomes secreted by hCPFs and observed that hCPFs-Exo was able to promote migration and tube formation in human umbilical vein endothelial cells (HUVECs). Advanced studies revealed hCPFs-Exo with low expression of miR-106b-5p was transferred into HUVECs, and decreased expression of miR-106b-5p could promote angiogenesis by targeting Angiopoietin 2 (Angpt2) via binding to its 3'-UTR. Furthermore, low levels of miR-106b-5p triggered overexpression of Angpt2, and significantly increased HUVEC migration and tube formation. Taken together, our results suggest that hCPFs-Exo transports low expressed exosomal miR-106b-5p to endothelial cells and promotes angiogenesis by overexpression of Angpt2.

Cytokeratin 13, Cytokeratin 17, and Ki-67 Expression in Human Acquired Cholesteatoma and Their Correlation With Its Destructive Capacity

OBJECTIVES

Cholesteatoma is a nonneoplastic destructive lesion of the temporal bone with debated pathogenesis and bone resorptive mechanism. Both molecular and cellular events chiefly master its activity. Continued research is necessary to clarify factors related to its aggressiveness. We aimed to investigate the expression of Ki-67, cytokeratin 13 (CK13) and cytokeratin 17 (CK17) in acquired nonrecurrent human cholesteatoma and correlate them with its bone destructive capacity.

METHODS

A prospective quantitative immunohistochemical study was carried out using fresh acquired cholesteatoma tissues (n=19), collected during cholesteatoma surgery. Deep meatal skin tissues from the same patients were used as control (n=8). Cholesteatoma patients were divided into 2 groups and compared (invasive and noninvasive) according to a grading score for bone resorption based upon clinical, radiologic and intraoperative findings. To our knowledge, the role of CK17 in cholesteatoma aggressiveness was first investigated in this paper.

RESULTS

Both Ki-67 and CK17 were significantly overexpressed in cholesteatoma than control tissues (P<0.001 for both Ki-67 and CK17). In addition, Ki-67 and CK17 were significantly higher in the invasive group than noninvasive group of cholesteatoma (P=0.029, P=0.033, respectively). Furthermore, Ki-67 and CK17 showed a moderate positive correlation with bone erosion scores (r=0.547, P=0.015 and r=0.588, P=0.008, respectively). In terms of CK13, no significant difference was found between cholesteatoma and skin (P=0.766).

CONCLUSION

Both Ki-67 and CK17 were overexpressed in cholesteatoma tissue and positively correlated with bone resorption activity. The concept that Ki-67 can be a predictor for aggressiveness of cholesteatoma was supported. In addition, this is the first study demonstrating CK17 as a favoring marker in the aggressiveness of acquired cholesteatoma.

Evaluation of bcl-2, bax and c-erbB-2 Levels in Chronic Otitis Patients with or without Cholesteatoma

Objective

The aim of this study was to evaluate bcl-2, bax, and c-erbB-2 expressions in primary and secondary acquired cholesteatoma and to indicate the role of apoptosis and accompanying increased cellular proliferation in the pathogenesis of cholesteatoma.

Methods

Samples obtained from the skin of the external ear canal (EEC) of patients operated for chronic otitis media (COM) without cholesteatoma constituted Group 1; samples from the EEC skin of patients in Group 3 operated for COM with cholesteatoma and from the EEC skin of patients in Group 4 constituted Group 2; samples obtained from the cholesteatoma matrix of patients operated for COM with primary acquired cholesteatoma constituted Group 3; and samples obtained from the cholesteatoma matrix of patients operated for COM with secondary acquired cholesteatoma constituted Group 4. The assessment of the positive cell ratio was based on the presence of the following findings and was semiquantitatively classified into four groups: 0, no staining; + cell staining (weak positive staining: 1%-33%); ++ cell staining (moderately positive staining: 34%-66%); and +++ cell staining (strong positive staining: 67%-100%).

Results

Comparison of the staining scores of bcl-2, bax, and c-erbB-2 revealed a statistically insignificant difference in the staining of samples obtained from the EEC skin (p>0.05). Decreased bcl-2 expression and increased bax and c-erbB-2 expressions were determined in primary and secondary acquired cholesteatoma epithelium compared with the EEC skin of patients operated for COM with or without cholesteatoma, and the differences were found to be statistically significant (p<0.05).

Conclusion

In acquired cholesteatoma epithelium, the finding of decreased bcl-2 expression as well as increased bax and c-erbB-2 expressions compared with the EEC skin is an indicator of the increase in both cellular proliferation and apoptosis.

In vivo over-expression of KGF mimic human middle ear cholesteatoma

We reported previously that keratinocyte growth factor (KGF), a mesenchymal cell-derived paracrine growth factor, plays an important role in middle ear cholesteatoma formation, which is characterized by marked proliferation of epithelial cells. Here, we investigated whether KGF, the main factor that induces cholesteatoma, overexpression in vivo results in the formation of cholesteatoma. Flag-hKGF cDNA driven by CMV14 promoter was transfected through electroporation into the external auditory canal (EAC) of rats once (short-term model) or five times on every fourth day (long-term model). Ears transfected with empty vector were used as controls. Successful transfection of plasmids into epithelial and stromal cells was confirmed by Flag immunohistochemistry. In the short-term model, the intensity of KGF protein was the strongest in hKGF transfected ear at day 4. KGF expression induced epithelial cell proliferation, reaching a peak level at day 4 and then decreased later, while in the long-term model, KGF expression in the EAC led to middle ear cholesteatoma formation. In conclusion, we described here a new experimental model of human middle ear cholesteatoma, and demonstrated that KGF and KGF receptor paracrine action play an essential role in middle ear cholesteatoma formation in an in vivo model.

Quantitative measurement of m-RNA levels to assess expression of cyclooxygenase-II, inducible nitric oxide synthase and 12-lipoxygenase genes in middle ear cholesteatoma

To assess expression of three main inflammatory genes, COX-II, ALOX-12 and i-NOS, quantitatively at transcriptional level in cholesteatoma matrix tissue. Ten patients who have chronic otitis media with primary acquired cholesteatoma were included in this study. Tissue samples obtained from cholesteatoma matrix and external ear canal skin (control tissue). Expression of the targeted genes (COX-II, i-NOS and LOX-12) was assessed using real-time quantitative polymerase chain reaction (RT-PCR) technique. The amount of COX2 mRNA was significantly higher in cholesteatoma matrix at transcriptional level (p = 0.038). There was no statistically significant difference regarding expression of iNOS and LOX12 mRNA levels (p > 0.05). There is a significant overexpression of the mRNA of COX-II in cholesteatoma matrix, which indicates a difference between the normal skin and cholesteatoma matrix at molecular level. COX-II gene overexpression seems to be associated with pathogenesis of cholesteatoma. This molecular change is similar to the molecular abnormalities observed in some benign and malignant neoplasms. Invasive and locally destructive nature of cholesteatoma may be due to COX-II overexpression. Absence of an increase in the gene expressions of i-NOS and LOX-12 in cholesteatoma matrix suggests that these mediators may not be related with the pathogenesis and evolution of cholesteatoma.

Canine aural cholesteatoma: a histological and immunohistochemical study

Canine aural cholesteatoma is an epidermoid cyst that forms in the middle ear cavity as a rare complication of otitis media but the aetiopathogenesis remains controversial. In the present study, 13 cases of canine aural cholesteatoma were investigated histologically and immunohistochemically and compared with cases of chronic otitis. The immunohistochemical investigation was performed using the following monoclonal antibodies: anti-cytokeratins (CK) 14, 16, 8/18, and 19, and anti-Ki67. The proliferative indexes (PIs) of cholesteatomata and otitis epithelium were calculated as the percentage of Ki67 positive nuclei/total nuclei. Histologically, the cholesteatomata were composed of a hyperplastic, hyperkeratotic epithelium (matrix) resting on a fibrous perimatrix, infiltrated by inflammatory cells and devoid of cutaneous adnexa. Immunohistochemically, the cholesteatoma epithelium was CK14- and CK16-positive, and CK8/18- and CK19-negative. A similar pattern of CK expression was found in otitis externa. In otitis media, ciliated epithelium stained CK8/18- and CK19-positive in all layers, CK14-positive in the basal layers, and CK16-negative. The mean PIs in cholesteatomata and otitides were 18.8 and 17.8, respectively. The immunohistochemical pattern of CK expression in cholesteatomata, when compared with chronic otitis, was suggestive of hyperproliferative epithelium, but its origin could not be demonstrated. Comparable PI values were obtained in cholesteatoma and in chronic otitis, which confirmed that Ki67 is a valuable indicator of a hyperproliferative state, but not a predictor of aggressiveness.

The effect of BMP-2, BMP-4 and BMP-6 on bone destruction of cholesteatoma presence

OBJECTIVE

The aim of our study was to investigate the relationship between the destruction of temporal bone structures, ossicular chain destruction, dissemination of cholesteatoma and the expressions of bone morphogenetic proteins (BMPs), BMP-2, BMP-4 and BMP-6 in patients with acquired cholesteatoma.

MATERIAL AND METHODS

This study was performed in a total of 80 patients with cholesteatoma and without cholesteatoma who had undergone surgery due to chronic otitis media. The patients were grouped as the study and the control groups. The study group comprised patients with primary acquired cholesteatoma, and the control group consisted of chronic otitis media patients without cholesteatoma. The samples were obtained from cholesteatoma tissue and the external acoustic meatus skin in study group patients and they were obtained from the external acoustic meatus skin only in control group patients. The Reverse Transcriptase Polymerase Chain Reaction method was used for the measurements of BMPs, BMP-2, BMP-4 and BMP-6 expressions. Polymerase Chain Reaction was studied by isolation of Ribonucleic Acid from the tissue samples.

RESULTS

When the expressions of BMP in the external acoustic meatus skin were compared between the study and the control groups, the BMPs, BMP-2 and BMP-6 were determined to have a statistically significant relation in the study group (p<0.05), but BMP-4 was not significant (p>0.05). When the expression of BMP in cholesteatoma tissue was investigated in the study group patients, the BMPs, BMP-2 and BMP-6 were determined with statistically significant positivity (p<0.05), but there was no significant positivity for BMP-4 (p>0.05). In the study group, there was no statistical significance between the expressions of BMPs, BMP-2, BMP-4 and BMP-6 in cholesteatoma tissue, in the external acoustic meatus skin, and temporal and ossicular chain destruction, and dissemination of cholesteatoma (p>0.05). A statistically significant positivity for BMPs expression in cholesteatoma tissue was determined in patients with destruction of the incus+malleus+stapes (p<0.05).

CONCLUSION

The expressions of BMPs, BMP-2 and BMP-6, were elevated in cholesteatoma tissue. Furthermore, the positivity of BMPs expression was statistically significant in patients with destruction of all the ossicles, and we think that this marker can be used for evaluation of the aggressiveness of cholesteatoma.

Role of Langerhans cells, Ki-67 protein and apoptosis in acquired cholesteatoma: prospective clinical study

OBJECTIVE

To investigate the role of Langerhans cells in the pathogenesis and clinical picture of middle-ear cholesteatoma.

SUBJECTS AND METHODS

The study included 40 patients operated upon for a diagnosis of chronic otitis due to acquired cholesteatoma.

RESULTS AND ANALYSIS

A closed surgical technique was used in 20 per cent of patients and an open technique in 80 per cent. Langerhans cells were more densely accumulated in cholesteatoma epithelium, compared with external ear canal skin (p < 0.001). Staining for Ki-67 protein was greater in cholesteatoma epithelium (p < 0.001) and Apo2.7 protein staining (indicating apoptosis) was more prominent (p < 0.001), compared with ear canal skin. Regarding significant relationships between clinical and pathological findings, staining for Ki-67 (p = 0.046) and Apo2.7 (p = 0.037) was more prominent in patients undergoing open versus closed surgery.

CONCLUSION

Using cell proliferation and apoptosis markers, a dense Langerhans cell infiltration was found to occur as a host response to middle-ear cholesteatoma.

Expression of keratinocyte growth factor (KGF) and its receptor in a middle-ear cavity problem

OBJECTIVES

To investigate the pathogenesis of one of the most troublesome conditions following ear surgery, a middle-ear cavity problem.

METHODS

Keratinocyte growth factor (KGF) and its receptor (KGFR), the ratio of proliferating epithelial cells using Ki-67, and the extent of infiltration of B cells and T cells were examined immunohistochemically in 10 ears with a cavity problem, 70 ears with cholesteatoma and 8 ears with normal skin at the retroauricular incision.

RESULTS

KGF was positive in 40% of cavity problem specimens, 37.5% of normal skin specimens, and was positive in 88% of cholesteatoma specimens (cavity problem vs. cholesteatoma, p=0.0004). The positive rate of KGFR in the cavity problem group (33.3%) was between those in cholesteatoma (60%) and normal skin (0%). In contrast to the cholesteatoma specimens, a significantly smaller number of Ki-67 labeling index (LI) was detected in the cavity problem specimens. B cell LI was significantly higher but T cell LI was significantly lower in the cavity problem specimens than in the cholesteatoma group.

CONCLUSIONS

Our present study indicated that the discordance of paracrine action between stromal KGF and epithelial KGFR with a large number of infiltrating B cells may play an important role in the pathogenesis of a cavity problem.

Evaluation of epithelial proliferation in paediatric and adult cholesteatomas using the Ki-67 proliferation marker

INTRODUCTION

The aggressiveness of cholesteatoma in children compared with adults is well known. However, the factors influencing the poorer prognosis of paediatric cholesteatoma are not well understood. This study compared the proliferative potential of paediatric cholesteatoma with that of adult cholesteatoma, using Ki-67 as a proliferation marker.

METHODS

A prospective study of 67 patients with aural cholesteatoma was performed. Thirty-eight adult and 29 paediatric cases were evaluated using clinical parameters including bone erosion, complications and extent of disease. A surgical specimen underwent histological evaluation and measurement of the proliferation index using Ki-67 labelling. Normal epithelium from a control group was also examined.

RESULTS

Cholesteatoma epithelium has a greater rate of proliferation than normal skin. There were however no statistical differences between the paediatric and adult cholesteatoma groups in terms of clinical behaviour or proliferation potential. Paediatric cholesteatoma was similar to adult cholesteatoma in terms of complications, bone erosion and disease spread.

CONCLUSION

Cholesteatoma is a disorder of epithelial proliferation. Although postulated to be more aggressive in children than adults, this study found no clinicopathological differences between paediatric and adult cases.

Comparative analysis of the epithelium stroma interaction of acquired middle ear cholesteatoma in children and adults

In the clinical setting, pediatric cholesteatomas frequently behave more aggressively than similar lesions in adults. The reason for the difference in behavior is still unclear. The purpose of the present study was to investigate the cell to cell and epithelial-stroma interaction of acquired cholesteatoma in adults and children and search for differences on the cellular level, which might explain the different behavior of these lesions. Operative specimens of 54 patients [40 adults (average age of 39.7 years), 14 children (average age of 8.3 years)] who underwent primary surgery for an acquired cholesteatoma of the middle ear were examined by histopathology and DNA-image cytometry (DNA-ICM). Immunohistochemical investigations included expression of proliferation markers (proliferation cell nuclear antigen and MIB-1) along with cell surface markers reflecting the cell-to-cell interaction (i.e. alpha1beta6-integrin, E-cadherin, I-CAM = CD54), and the epithelial to stroma interaction (i.e. alphav and beta3 intergin chains, V-CAM = CD106, CD44v6 and fibronectin). Pediatric cholesteatomas demonstrated higher incidence of acute inflammation and more extensive disease relative to those from the adults. Indices of DNA-ICM, however, revealed normal diploid DNA content in both groups. Higher proliferation scores occurred in the pediatric group compared to adult cholesteatoma. Cell surface markers and cell adhesion molecules were equally expressed in both groups except alpha1beta6-integrin and fibronectin, which were over expressed in pediatric cholesteatomas. Statistically, however, these differences showed only a trend towards significance. According to the results of the present study, pediatric and adult cholesteatomas do not show any marked differences on the cellular level. Thus the observed clinical more aggressive behavior of pediatric cholesteatoma is likely due to other secondary factors such as more intense inflammation, disturbed middle ear ventilation or the diminished calcium salt content of pediatric bone.

Pathogenesis of sinus cholesteatoma

The aim of the present study was to provide evidence for the establishment of sinus cholesteatoma, defined as postero-superior pars tensa retraction extending into the posterior tympanum and tympanic sinuses.

BACKGROUND

There is clinical evidence for formation of a retraction, but there is a lack of explanation for the transition from a retraction pocket to an active and expanding sinus cholesteatoma. Epidemiological studies on incidence of postero-superior retractions of pars tensa and follow-up studies on patients with similar pars tensa retractions were performed. Additionally, expression of proliferation marker and analysis of basement membrane were studied in samples of sinus cholesteatoma. The prevalence of pars tensa pathology was between 9.2 and 24% of investigated ears. In children with manifest secretory otitis there were some sinus cholesteatomas and 5-6% severe retractions, some of those became pre-cholesteatomas, requiring treatment and controls. Immunohistochemistry of sinus cholesteatomas showed that proliferating keratinocytes were very often found within epithelial cones growing towards the underlying stroma. These growth cones exhibit focal discontinuities of the basement membrane especially in areas of intense subepithelial inflammation. As a possible explanation based on clinical and immunohistochemical findings, we propose a four-step concept for pathogenesis of sinus cholesteatoma combining the retraction and proliferation theory: (1) The retraction pocket stage. (2) The proliferation stage of the retraction pocket, subdivided in (a) Cone formation, (b) Cone fusion. (3) Expansion stage of attic cholesteatoma. (4) Bone resorption.

Etiopathogenesis of cholesteatoma

Cholesteatoma is a destructive lesion of the temporal bone that gradually expands and causes complications by erosion of the adjacent bony structures. Bone resorption can result in destruction of the ossicular chain and otic capsule with consecutive hearing loss, vestibular dysfunction, facial paralysis and intracranial complications. Surgery is the only treatment of choice. The etiopathogenesis of cholesteatoma, however, is still controversial. This review was designed to understand the reasons for these disparities and to reduce or eliminate them. Future studies focused on developmental, epidemiological, hormonal and genetic factors as well as on treatment are likely to contribute to further understanding of cholesteatoma pathogenesis.

Immunohistochemical Investigations on External Auditory Canal Cholesteatomas

OBJECTIVE

The aim of the study was to analyze the biological behavior of external auditory canal cholesteatoma (EACC). The expression and distribution of relevant markers such as transforming growth factor-alpha (TGF-alpha), epidermal growth factor-receptor (EGFR), and the proliferation marker MIB 1 were studied in comparison with normal auditory meatal skin.

BACKGROUND

EACC are uncommon and knowledge concerning etiology and pathogenesis is limited. Whether this is a unique entity remains controversially discussed.

MATERIALS AND METHODS

Immunohistochemical methods were used to study the expression and distribution TGF-alpha, EGFR, and the proliferation marker MIB 1 on 15 tissues samples. Only the spontaneous form of EACC was included in this study.

RESULTS

Positive immunoreactivity for the proliferation marker MIB 1 could be demonstrated in keratinocytes in the basal and suprabasal layers of the epithelium. The number of MIB 1-positive proliferating cells in cholesteatoma was significantly higher than in normal external auditory skin. Cholesteatoma epithelium also showed an enhanced expression of TGF-alpha and EGFR. Inflammatory infiltrate was observed in the perimatrix to various degrees.

CONCLUSION

These results suggest that similar to the middle ear cholesteatoma, a chronic inflammatory process underlies the EACC, and the inflammatory stimuli may alter keratinocyte proliferation.

Characterization of the levels of expression of retinoic acid receptors, galectin-3, macrophage migration inhibiting factor, and p53 in 51 adamantinomatous craniopharyngiomas

OBJECT

Craniopharyngiomas are histopathologically defined as benign tumors that can behave very aggressively at the clinical level. They can originate from different types of embryonal epithelial tissue in which correct spatiotemporal regulation has been disrupted at the effector production level. The goal of this study was to determine the efficacy of using selected biological markers to distinguish between recurring and nonrecurring craniopharyngiomas.

METHODS

The authors used computer-assisted microscopy to determine quantitatively the immunohistochemical levels of expression of selected markers, including retinoic acid receptors (RARs), as response elements to retinoic acid in a series of 51 adamantinomatous craniopharyngiomas. These tumors may also originate as the result of physiological defects in the apoptosis-mediated elimination of embryological remnants of epithelial tissue. Galectin-3, p53, and the macrophage migration inhibiting factor (MIF) are known to play crucial roles in these processes. The authors quantitatively determined the levels of expression of these substances in this series of 51 craniopharyngiomas. The data show that all craniopharyngiomas were immunoreactive for RARalpha, whereas their immunoreactivity for RARbeta and RARgamma varied dramatically from one case to another. Craniopharyngiomas with low levels of RARbeta and high levels of RARgamma are more likely to recur than those with higher levels of RARbeta and lower levels of RARgamma. Rapidly recurring craniopharyngiomas also show significantly lower levels of expression of galectin-3 and MIF than nonrecurring or slowly recurring cases. Few tumors exhibited p53 immunopositivity.

CONCLUSIONS

The data indicate that even in the so-called adamantinomatous group of craniopharyngiomas, several subgroups with different clinical behavior patterns can be identified on the basis of differentiation markers relating mainly to the presence or absence of RARbeta and RARgamma.

Possible involvement of keratinocyte growth factor and its receptor in enhanced epithelial-cell proliferation and acquired recurrence of middle-ear cholesteatoma

Middle-ear cholesteatoma is characterized by enhanced proliferation of epithelial cells and granular tissue formation. However, the molecular mechanism underlying these pathological changes is largely unknown. Keratinocyte growth factor (KGF) is a mesenchymal cell-derived paracrine growth factor that specifically stimulates epithelial cell proliferation. In the present study, we investigated the possible involvement of KGF and its receptor, KGFR, in the pathogenesis of cholesteatoma using in situ hybridization and immunohistochemistry, respectively. We examined 56 cholesteatoma specimens, and 8 normal skin areas as control. KGF and KGFR expression was examined by immunohistochemistry using rabbit anti-human KGF and anti-human KGFR polyclonal antisera raised in our laboratories against synthetic peptides corresponding to parts of human KGF and KGFR, respectively. KGF protein and mRNA were detected exclusively in stromal fibroblasts and infiltrating T lymphocytes in 80% of cholesteatoma cases, whereas KGFR protein and mRNA were localized in the epithelium in 72% of cases. Assessment of the proliferative activity of cholesteatoma using the labeling index for Ki-67 showed a significantly higher Ki-67 labeling index (66%) in KGF+/KGFR+ cases than other cases. There was a significant correlation between KGF+/KGFR+ expression and recurrence. Our results indicate the possible involvement of both KGF and KGFR in enhanced epithelial cell proliferative activity and recurrence of cholesteatoma.

p53 Expression and keratinocyte hyperproliferation in middle ear cholesteatoma

Keratinocytes in middle ear cholesteatoma have hyperproliferative properties. There is controversy regarding the role of p53 and its effect on cellular proliferation in cholesteatoma. This study was instituted to examine this. Cholesteatoma and deep meatal skin control specimens were analysed for MIB-1 (n = 7, controls = 7), a marker of cellular proliferation, and p53 (n = 17, controls = 17) expression by immunocytochemistry. Expression of p53 was minimal or absent in both cholesteatoma and controls (P = 0.2). MIB-1 expression was higher, but not significantly so, in cholesteatoma than in controls (P = 0.09). Our study has shown no significant p53 expression in cholesteatoma epithelium. This suggests that there is no dysfunction in the p53-mediated cell cycle control mechanisms in cholesteatoma.

Imunoexpressão da citoqueratina 16 e do antígeno nuclear Ki-67 no colesteatoma adquirido da orelha média

Introdução: Ocolesteatoma da orelha média é caracterizado pela presença de epitélio escamoso estratificado queratinizado nesta cavidade, causando destruição óssea e podendo levar a complicações. Algumas substâncias como a citoqueratina 16 e o Ki-67, marcadores de proliferação celular, vêm sendo utilizadas para estudar essa doença. A CK 16 é um filamento protéico, situado no citoplasma das células epiteliais, característico de epitélios hiperproliferativos. O Ki-67 é um antígeno nuclear que aparece nas células em estágio de proliferação. Objetivo: O objetivo deste trabalho foi estudar a imunoexpressão da CK 16 e do Ki-67 no colesteatoma adquirido. Forma de estudo: Clínico prospectivo. Material e Método: Foram colhidas amostras de colesteatoma de 31 pacientes submetidos à cirurgia otológica, sendo 20 adultos e 11 crianças, no período de 1998 e 2000. Essas amostras foram submetidas à análise histológica e imuno-histoquímica para estudo da expressão da CK 16 e do Ki-67 na matriz do colesteatoma. Resultado: A análise dos resultados mostrou a presença da CK 16 nas camadas suprabasais da matriz do colesteatoma e, do Ki-67, na camada basal, estendendo-se para as camadas suprabasais e, inclusive, para a camada apical da matriz. A reação aos anticorpos anti-CK 16 e Ki-67 foi heterogênea. A correlação entre a CK 16 e o Ki-67 suprabasal com variáveis morfológicas, como acantose do epitélio e hiperplasia da camada basal formando cones epiteliais em direção à perimatriz, foi positiva e significativa. Também houve relação positiva e significativa entre a CK 16 e o Ki-67 suprabasal e apical. Conclusão: Esses resultados permitem concluir que o colesteatoma tem características hiperproliferativas, expressando a CK 16 e o Ki-67 na sua matriz.

[Alterations of the basal membrane in middle ear cholesteatoma]

Cholesteatoma epithelium is characterized by a keratinocyte disregulation accompanied by destruction of the ossicles and other bony parts of the temporal bone. Immunohistochemical methods using antibodies to fibronectin, tenascin and metalloproteinases were used to assess the alterations of the instrinsic and extrinsic components of the basement membrane. Spatial orientation of the basement membrane was preserved in histological sections. Collagen type IV, tenascin, fibronectin, basic fibroblastic growth factor (bFGF), and matrix metalloproteinases (MMPs) are related to the matrix, perimatrix of normal or pathological tissues. They were studied immunohistologically in twenty cholesteatomas, eight samples of normal auditory canal skin, and six specimens of normal middle ear mucosa. Cholesteatomas displayed alterations of the basal membrane, with presence of MMPs and a linear immunoreactivity for collagen type IV and laminin, disrupted in areas with intense inflammation. The electronic microscope revealed protrusions, duplications, thickening and disruptions of the lamina densa of the basement membrane. Thus, we conclude, that MMPs and bFGF could play an important role maintaining the proliferative activity and the aggressive behaviour of cholesteatoma in the middle ear.

Expression patterns of p27Kip1 and Ki-67 in cholesteatoma epithelium

OBJECTIVES

The cell cycle must be involved in cell proliferation of the epithelium of middle ear cholesteatoma Cyclins and cyclin-dependent kinase (CDK) complexes have important regulatory roles during cell cycle progression. Cyclin-CDK complexes are in turn regulated by the cyclin-dependent kinase inhibitors (CDKIs), which generally inhibit cell cycle progression. One of the important CDKI members is p27(Kip1). The goal of this study is to evaluate the expression of p27(Kip1) and Ki-67, a proliferation marker, in cholesteatoma and in the skin of the external ear canal.

METHODS

The expressions of p27(Kip1) and Ki-67 in cholesteatoma epithelium (n = 20) and ear canal epithelium (n = 7) were investigated by an immunohistochemical technique.

RESULTS

In cholesteatoma epithelium specimens, the expression of p27(Kip1) was observed from the parabasal layer to the granular layer, but not in the basal layer. Ki-67 was expressed dominantly in the basal and parabasal cell layers. Their expressions tend to be increased compared with their expressions in the normal ear canal skin. The expression pattern of the proliferation marker Ki-67 in the epithelial layers of two groups was inversely related to the expression of p27(Kip1).

CONCLUSIONS

In cholesteatoma, the expressions of CDKI and Ki-67 were both increased in this study. The ability to inhibit proliferative activity was also increased in the cholesteatoma epithelium. The expression pattern of the proliferation marker Ki-67 in the epithelial layers was inversely related to the expression of p27(Kip1). Not only is the proliferation activity increased, but also the ability to inhibit hyperproliferation is increased in the cholesteatoma epidermis. Despite increased proliferative activity in the cholesteatoma epidermis, epithelial cells still retain the capability to prevent cell cycle arrest by means of p27(Kip1).

Determination of the levels of expression of sarcolectin and calcyclin and of the percentages of apoptotic but not proliferating cells to enable distinction between recurrent and nonrecurrent cholesteatomas

OBJECTIVES

To investigate in a series of cholesteatomas 1. whether subgroups of cholesteatomas with specific proliferative/apoptotic features exhibit distinct differentiation markers and 2. whether these different subgroups identified at the biological level relate to specific groups of clinically identified cholesteatomas.

STUDY DESIGN

Analysis of 55 cholesteatomas resected by the same surgeon, by means of canal wall up and canal wall down surgical procedures.

METHODS

Two differentiation markers were used: biotinylated sarcolectin (to identify sarcolectin-binding sites) and a monoclonal antibody directed against calcyclin (which is the S100A6 protein). The growth pattern in cholesteatomas was characterized at three distinct levels: 1. the cell proliferation level determined by means of the MIB-1 antibody, which enables the Ki-67 cell-cycle-related antigen to be identified on archival material; 2. the apoptosis level determined by means of the in situ labeling of nuclear DNA fragmentation (TUNEL staining); and 3. the p53 tumor suppressor gene-related product determined by means of p53 immunohistochemistry.

RESULTS

The cholesteatomas that exhibited the highest proportion of apoptotic cells were those which exhibited the highest level of sarcolectin-binding sites (i.e., sialic acids). In contrast, the cholesteatomas exhibiting the lowest level of both proliferation and apoptosis showed the highest level of calcyclin. Recurrent cholesteatomas can be identified from nonrecurrent ones on the basis of three features, namely, the level of apoptotic cells, the way in which the apoptotic cells are distributed (i.e., homogeneously vs. heterogeneously), and the percentage of calcyclin-positive cells.

CONCLUSIONS

The present data emphasize the existence of distinct subgroups of cholesteatomas identifiable at both cell kinetic and differentiation levels. Some of the biological variables used here to identify distinct biological subgroups of cholesteatomas in turn enabled some biological variables to be identified, so making it possible to classify the cholesteatomas in terms of recurrence versus nonrecurrence.

Cholesteatoma in children

Cholesteatoma in children is generally considered to be more aggressive and destructive than in adults. Each otologic surgeon has experienced widely extended cholesteatomas in children with large pneumatized mastoid processes. In this paper, we want to present clinical and experimental observations which imply that the destructive potential in children is similar to that in adults. Factors and observations that have led to the assumption that cholesteatoma in children is more aggressive will be discussed. Based on our experience and the literature, we tried to distill the current and leading thoughts concerning this intriguing entity.

Basement membrane in middle ear cholesteatoma. Immunohistochemical and ultrastructural observations

We investigated the distribution of basement membrane zone (BMZ) components collagen type IV, collagen type VII, and fibronectin in human middle ear cholesteatoma, auditory meatal skin, and middle ear mucosa using both immunohistochemical and ultrastructural methods. Collagen type IV immunoreactivity of skin and middle ear mucosa is continuous in the BMZ, whereas cholesteatoma frequently showed absent immunoreactivity or focal discontinuities. Collagen type VII immunoreactivity is detected similarly within the BMZ of cholesteatoma and skin. Fibronectin immunoreactivity is observed within the dermoepithelial junction of skin and middle ear mucosa. In cholesteatoma, however, fibronectin immunoreactivity is markedly increased within the extrinsic BMZ and the subepithelial connective tissue. The ultrastructural arrangement of the BMZ of cholesteatoma is like that of skin; however, it exhibits distinct alterations of the lamina fibroreticularis and lamina densa. Our results outline cholesteatoma as a disease with disturbed cell matrix interactions analogous to those of wound reepithelialization.

Immunobiological peculiarities of cholesteatoma in children: quantification of epithelial proliferation by MIB1

Cholesteatoma in children is characterized by a more extensive and rapid growth in the middle ear and mastoid cavities. The growth characteristics of the cholesteatoma in 20 children were studied using the monoclonal antibody MIB 1, which recognizes a nuclear antigen expressed by cells in the G1, S, and G2/M phases. Specimens of normal adult auditory meatal skin (n = 15) and adult cholesteatoma (n = 15) served as controls. The tissue specimens were prepared for immunohistochemical examination using the alkaline phosphatase-antialkaline phosphatase method and an automatic image analyzer. Specimens of normal skin revealed an average MIB 1 score of 9.2 +/- 3.10%. Child and adult cholesteatomas showed higher values. The average MIB 1 score was higher in child cholesteatoma (42 +/- 9.4%) than in adult cholesteatoma (28.2 +/- 6%). This difference was statistically significant (P<.01). Our results confirm a significant increase of the proliferative rate of cholesteatoma keratinocytes in children, giving an explanation for the more aggressive clinical behavior observed in these patients.