Aberrant accumulation of p53 associates with Ki67 and mitotic count in benign skin lesions

Ursolic Acid Formulations Effectively Induce Apoptosis and Limit Inflammation in the Psoriasis Models In Vitro

Psoriasis, a prevalent inflammatory skin disorder affecting a significant percentage of the global population, poses challenges in its management, necessitating the exploration of novel cost-effective and widely accessible therapeutic options. This study investigates the potential of ursolic acid (UA), a triterpenoid known for its anti-inflammatory and pro-apoptotic properties, in addressing psoriasis-related inflammation and keratinocyte hyperproliferation. The research involved in vitro models employing skin and immune cells to assess the effects of UA on psoriasis-associated inflammation. The presented research demonstrates the limiting effects of UA on IL-6 and IL-8 production in response to the inflammatory stimuli and limiting effects on the expression of psoriatic biomarkers S100A7, S100A8, and S100A9. Further, the study reveals promising outcomes, demonstrating UA's ability to mitigate inflammatory responses and hyperproliferation of keratinocytes by the induction of non-inflammatory apoptosis, as well as a lack of the negative influence on other cell types, including immune cells. Considering the limitations of UA's poor solubility, hybrid systems were designed to enhance its bioavailability and developed as hybrid nano-emulsion and bi-gel topical systems to enhance bioavailability and effectiveness of UA. One of them in particular-bi-gel-demonstrated high effectiveness in limiting the pathological response of keratinocytes to pro-psoriatic stimulation; this was even more prominent than with ursolic acid alone. Our results indicate that topical formulations of ursolic acid exhibit desirable anti-inflammatory activity in vitro and may be further employed for topical psoriasis treatment.

Comparison of p53 immunohistochemical staining in differentiated vulvar intraepithelial neoplasia (dVIN) with that in inflammatory dermatoses and benign squamous lesions in the vulva

AIMS

Differentiated vulvar intraepithelial neoplasia (dVIN), the precursor lesion to human papillomavirus-independent vulvar squamous cell carcinoma (VSCC), can be difficult to distinguish from vulvar inflammatory dermatoses. Our goal was to determine if p53 could be a useful biomarker for dVIN, by characterizing p53 percentage, intensity and patterns of staining in dVIN and its histological mimics.

METHODS AND RESULTS

We studied p53 immunohistochemical staining patterns in 16 dVIN cases and 46 vulvar non-neoplastic squamous lesions [12 lichen sclerosus (LS); seven lichen simplex chronicus; three lichen planus (LP); six psoriasis; 13 spongiotic dermatitis (SPO); and five candidiasis]. dVIN cases were adjacent to a p16-negative invasive VSCC in resection specimens. All dVIN cases showed null-type or moderate to strong uniform p53 staining in >70% of basal cells, with moderate to strong continuous parabasal staining extending to two-thirds of the epidermis. This was in contrast to weak or weak to moderate patchy p53 staining in the majority of other lesions. Moderate to strong and increased basal p53 staining (≥70%) was also observed in a subset of LS cases (5/12, 42%), LP cases (1/3, 33%), and SPO cases (36%, 4/11); however, in all categories, this was limited to the basal layer, and any staining in the parabasal layers was patchy.

CONCLUSION

Strong and uniform p53 staining of basal cells, extending into the parabasal layers, and a complete absence of staining (null type) is useful in distinguishing dVIN from other mimics in the vulva. p53 staining of lesser intensity or quantity, particularly basal overexpression only, overlaps with that in vulvar inflammatory lesions.

Ki-67 and p16 Immunostaining Differentiates Pagetoid Bowen Disease From "Microclonal" Seborrheic Keratosis

OBJECTIVES

We observed keratoses with "clonal" nests present as numerous tiny collections, in which cells in "pagetoid" array are found, a configuration we termed microclonal seborrheic keratosis (MSK). To better distinguish MSK from pagetoid Bowen disease (PBD), we investigated use of immunohistochemical staining.

METHODS

Biopsy specimens of 26 MSKs, 17 PBDs, and 11 borderline cases were reviewed for histopathology and stained with p53, Ki-67, and p16.

RESULTS

High expression of Ki-67 and p16 was observed in 12 (80%) of 15 PBDs and in one (4%) of 23 MSKs. Low expression of p16 and high expression of Ki-67 were observed in 16 (70%) of 23 MSKs and in two (13%) of 15 PBDs. Expression of p16 was elevated in 12 (80%) of 15 PBDs and in three (13%) of 23 MSKs (P < .0001).

CONCLUSIONS

We describe a "microclonal" variant of seborrheic keratosis with morphology sometimes challenging to distinguish from PBD. High expression of p16 and Ki-67 or p16 alone favors the diagnosis of PBD over MSK.

Expression and potential role of cellular retinol binding protein I in psoriasis

Psoriasis is a diffuse chronic skin disorder characterized from accelerated epidermal turnover and inflammatory cell infiltrate. Retinoids influence keratinocyte proliferation and differentiation as well as inflammatory response. Cellular retinol binding protein (CRBPI) regulates intracellular vitamin A bioavailability and contributes to maintain skin homeostasis. The aim of present study was to investigate the expression of CRBPI and its role in the pathogenesis of skin psoriasis. Immunohistochemistry revealed more diffuse and increased CRBPI expression in all epidermal layers of human psoriatic lesions except in the stratum corneum. An imiquimod-induced psoriatic-like model documented the increase of skin lesional area and severity index score as well as of the severity of microscopic features as parakeratosis, papillomatosis and spongiosis in CRBPI-knockout compared to wild-type mice, associated to the increased keratinocyte CK17 and Ki-67 expression and the reduction of CK1, CRABPII and RXRα. Gene array of imiquimod-induced psoriatic skin documented the greater up-regulation of EGF/PDGF-related genes and down-regulation of EGR1 and pro-inflammatory IL-related genes in CRBPI-knockout compared to wild-type mice. Finally, CRBPI transfection in HaCaT cells increased AKT and NF-κB-related genes and proteins and down-regulated IL-2, IL-6 and IL-8 pro-inflammatory signalling. Although not recognized as a psoriatic susceptibility gene in our cohort of patients, the present data strongly supported the potential role of CRBPI to sustain keratinocyte proliferation and differentiation and to counteract pro-inflammatory genes expression in psoriatic lesions.

p53 Protein Expression and Cell Proliferation in Non-Neoplastic and Neoplastic Proliferative Skin Diseases

Aims and background

The p53 protein is essential for the regulation of cell proliferation and its aberrant accumulation is usually seen in malignant tumors but also occurs in squamous epithelium of inflammatory skin diseases characterized by hyperproliferation. The aim of this study is to elucidate the role of the p53 tumor suppressor protein in the pathogenesis of different hyperproliferative, non-malignant and malignant skin diseases, and to determine the association between p53 overexpression and cell proliferation. We also investigated the influence of aging on p53 and Ki-67 protein expression.

Methods

One hundred and fifty skin specimens divided into 30 samples each of normal skin (NS), psoriatic skin (PS), keratoacanthomas (KA), basal cell carcinomas (BCC), and squamous cell carcinomas (SCC) were examined immunohistochemically to assess p53 and Ki-67 protein expression.

Results

p53 immunostaining of NS, PS, KA, BCC and SCC was detected in 39.0%, 46.7%, 66.7%, 80% and 86.7% of cases, respectively. Median values and ranges of p53 protein expression were as follows: 0.0% (range, 0.0–1.8%) in NS, 0.0% (range, 0.0–6.5%) in PS, 9.2% (range, 0.0–24.0%) in KA, 19.3% (range, 0.0–48.1%) in BCC and 30.1% (range, 0.0–68.1%) in SCC. p53- and Ki-67-positive cells were present in basal (NS) and suprabasal layers (PS), and not only in cancer nests of KA, BCC and SCC but also in dysplastic and even morphologically normal epidermis adjoining cancers. The positivity of p53 and Ki-67 proteins differed significantly among the groups, with no differences in p53 expression between NS and PS and in Ki-67 expression between PS and KA. Within all groups there was a significant correlation between p53 and Ki-67 expression. Lesion location and patient age, with the exception of location in PS and age in BCC, were significantly related to p53 and Ki-67 expression in all groups.

Conclusions

Our findings suggest that p53 overexpression occurs mainly in neoplastic skin lesions, although it may also occur in squamous epithelium of inflammatory skin diseases such as PS, as well as in normal skin epithelium. It is associated with cell proliferation in normal as well as altered epithelium. p53 protein overexpression is an age-related process and significantly associated with sun exposure, especially in NS and PS but also in KA and SCC. Our findings suggest that Ki-67 rate and p53 protein expression reflect the degree of malignancy in the examined cutaneous neoplasms.

Predictive Role of p53 Protein as a Single Marker or Associated with ki67 Antigen in Oral Leukoplakia: A Retrospective Longitudinal Study

Oral leukoplakia (OL) is the most common potentially malignant lesion of the oral cavity. Immunohistochemical analysis of p53 and Ki67 proteins is a simple and inexpensive method widely used in non-dysplastic OLs to reveal lesions predicted to develop oral cancer. The present longitudinal study evaluated the predictive role of p53 and Ki67 proteins alone or in combination in a group of OLs without dysplasia followed for many years. Seventy-seven OL patients referred to our Department between January 2006 and October 2013 underwent histochemical analysis of p53 and Ki67 expression. OLs were considered at high risk in the presence of either high p53 expression (>20%), or low/normal p53 expression associated with high Ki67 expression (Ki67/p53 ratio >3). Seven OLs evolved to OSCC during the follow-up period. Three cases had p53 overexpression, while four had a high Ki67/p53 ratio. Statistical significance was reached when samples with p53 overexpression were combined with samples with high Ki67/p53 ratio (Chi square 5.3; p<0.02). The combined immunohistochemical expression of p53 and Ki67 proteins could be a useful and simple molecular marker for early detection of non-dysplastic OLs at risk of developing oral cancer.

The "intraepidermal epithelioma" revisited: immunohistochemical study of the borst-jadassohn phenomenon

The true nature of the so-called intraepidermal epithelioma of Borst-Jadassohn is poorly understood; whether this represents a distinct tumor or a morphological phenomenon [Borst-Jadassohn phenomenon (BJP)] shared by different entities has been debated. So far, no detailed immunohistochemical studies have been performed to address this issue. The aim of our study was to get further insight into the pathogenesis of the intraepidermal epithelioma of Borst-Jadassohn/BJP. Tumors showing the BJP [mainly clonal seborrheic keratoses (cSK) and clonal Bowen disease (cBD)] were studied and compared with typical (nonclonal) counterparts. Cell nests in cSK, cBD, hidroacanthoma simplex (HS), and porocarcinoma (PC) showed strong expression of epidermal growth factor-receptors (EGF-R), Ki-67, p63, and p53. Cell nests of clonal SK and HS (but not of clonal BD or PC) expressed keratin 5/6. The expression of E-cadherin and the number of CD1a+ Langerhans cells were reduced within the nests of all lesions, whereas melanocytes were increased in all of them. Keratins 7 and 19 were not expressed in any of the lesions. Tumors showing the BJP exhibit some immunohistochemical differences, suggesting that they represent separate entities. However, they all show strong expression of EGF-R within intraepidermal keratinocyte nests, suggesting that the epithelial growth factor pathway plays a role in the development of the BJP.

Possibilities of enhancement of the efficiency of complex psoriasis treatment

The article describes an assessment of the effect of Glutoxim, a drug used for complex treatment of psoriatic patients, on the dynamics of clinical symptoms, quality of life and laboratory indices. Faster and more complete regression of the disease, improvement of patients' life quality, normalization of hepatic function indices and increased periods of disease remission were observed in the main group of patients who received Glutoxim.

Expressions of p53, cyclinD1 and histopathological features in basal cell carcinomas

BACKGROUND

We planned this study to analyze probable associations between p53, cyclinD1, Ki67 and histopathological features in basal cell carcinomas (BCC).

METHODS

Histological differentiation types, histological growth patterns and tissue responses were analyzed in 50 cases of BCC. In immunohistochemical analysis, p53, cyclinD1 and Ki67 antibodies were investigated. P53 expression was evaluated based on a cut-off value of 25% positivity. CyclinD1 expression was graded from 0 to 3+ according to the percentage of positive nuclear staining. The percentage of positively staining cells for Ki67 was recorded.

RESULTS

The following significant correlations were detected. Solid infiltrative type differentiation was related to the infiltrative histological growth pattern. The rates of p53 positivity and severe fibrosis in the groups of mixed and infiltrative growth patterns were higher than others. Besides, p53-positive cases showed more severe fibrosis and had a higher mean value for Ki67 index. Epidermal p53 and cyclinD1 clones in normal epidermal areas adjacent to tumors were noticed in 42% and 52% of the cases, respectively.

CONCLUSIONS

P53 expression seems to be related to Ki67 index and some histopathological features of BCC, such as infiltrative histological growth pattern and probably fibrosis.

Predictive Role of p53 Protein as a Single Marker or Associated to Ki67 Antigen in Oral Carcinogenesis

p53 over-expression has been proposed as a reliable marker associated to oral carcinogenesis, although only about 50% of oral carcinomas (OSCC) are associated with p53 over-expression and even p53-negative lesions can progress to OSCC. The aim of the study was to determine whether the combination of p53 over-expression and p53 low-expression associated with Ki67 over-expression (high Ki67/p53 ratio) could lead to a more sensitive parameter. Immunohistochemical expression of Ki67 and p53 was measured in 54 specimens from OSCC; 27 specimens from moderate/severe epithelial dysplasia; 32 specimens from oral leukoplakias without epithelial dysplasia, and 13 specimens with normal epithelium. p53 over-expression was found in 31 (53%) samples from OSCC, in 10 (37%) samples from severe dysplasias, and in 5 (15%) samples from non-dysplastic lesions, while the combination of high p53 values with high Ki67/p53 ratio was observed in 93% of OSCC, in 81% of dysplastic lesions, and in 50% of non-dysplastic lesions. This parameter may have a clinical implication to detect early lesions with an impairment of p53 pathway, and probably at risk of progress to OSCC.

Protective Effect of Sanguinarine on Ultraviolet B-mediated Damages in SKH-1 Hairless Mouse Skin: Implications for Prevention of Skin Cancer

Excessive exposure of solar ultraviolet (UV) radiation, particularly its UVB component (280-320 nm), to human skin is the major cause of skin cancers. UV exposure also leads to the development of precancerous conditions such as actinic keratosis and elicits a variety of other adverse effects such as sunburn, inflammation, hyperplasia, immunosuppression and skin aging. Therefore, there is a need to intensify our efforts towards the development of novel mechanism-based approaches/agents for the protection of UVB-mediated damages. Chemoprevention is being investigated as a potential approach for the management of UV damages including skin cancer. We have earlier shown that sanguinarine, a benzophenanthridine alkaloid, inhibits UVB exposure-mediated damages in HaCaT keratinocytes. In this study, to determine the relevance of our in vitro findings to in vivo situations, we assessed the effects of sanguinarine on UVB-mediated damages in SKH-1 hairless mice. Our data demonstrated that a topical application of sanguinarine (5 micromol 0.3 mL(-1) ethanol per mouse), either as a pretreatment (30 min prior to UVB) or posttreatment (5 min after UVB), resulted in a significant decrease in UVB-mediated increases in skin edema, skin hyperplasia and infiltration of leukocytes. Further, sanguinarine treatments (pre and post) also resulted in a significant decrease in UVB mediated (1) generation of H2O2 and (2) increases in the protein levels of markers of tumor promotion/proliferation viz. ornithine decarboxylase (ODC), proliferating cell nuclear antigen (PCNA) and Kiel antigen-67. Based on this data, we suggest that sanguinarine could be developed as an agent for the management of conditions elicited by UV exposure including skin cancer. However, further detailed studies are needed to support this suggestion.

Apoptosis, P53 and Bcl-2 expression in response to topical calcipotriol therapy for psoriasis

BACKGROUND

The histopathologic changes characteristic of psoriasis might be related to suppressed apoptosis. The P53 and Bcl-2 proteins play a central role in the regulation of apoptosis. This study aimed to evaluate P53 and Bcl-2 expression and apoptotic cells in the psoriatic skin before and after topical calcipotriol therapy.

METHODS

Skin biopsies were obtained from nonlesional and lesional skin of 10 patients with generalized plaque psoriasis before and after treatment with topical calcipotriol ointment. The P53 and Bcl-2 expression was evaluated using immunoperoxidase technique and apoptotic cells by the terminal deoxynucleotide transferase (TdT) mediated deoxyuridine triphosphate nick end labeling (TUNEL) method.

RESULTS

After topical calcipotriol therapy, keratinocytes of psoriatic skin showed significant decrease of P53 (P = 0.002) and increase of Bcl-2 (P = 0.01) expression. On the other hand lymphocytes showed significant decrease of Bcl-2 (P = 0.01). There were no apoptotic cells before treatment but after calcipotriol therapy, apoptosis was more detectable in keratinocytes than in lymphocytes.

CONCLUSIONS

The results of the study suggested that one of the actions of calcipotriol in psoriasis might be exerted through induction of apoptosis, especially of keratinocytes, through a P53-independent pathway. Meanwhile, suppression of Bcl-2 expression in lymphocytes may promote apoptosis of dermal lymphocytes leading to healing of psoriasis.

Expression of p53 in lesions and unaffected skin of patients with plaque-type and guttate psoriasis: A quantitative comparative study

Psoriasis is a common inflammatory and hyperproliferative skin disease characterized by hyperproliferation of keratinocytes. The pathogenesis of psoriasis has yet to be determined. The control of cell growth is a delicately balanced process, regulated by external signals or the internal genetic program of an individual cell. In psoriasis, these processes are disturbed and some candidate genes like p53 are suspected of being involved in the pathogenesis of the disease. The p53 protein is essential for the regulation of cell proliferation. The study was performed on 32 patients with psoriasis (24 plaque type, eight guttate type). Biopsy specimens for immunohistochemical determination of p53 protein expression were collected from both the lesional and the nonlesional skin sites that were not exposed to sun in all of the patients (n = 32). Taking the ultraviolet (UV) exposure of the skin into consideration, a third skin sample was taken from each patient (n = 7) who had lesions on the sun-exposed areas. Immunohistochemical assessment of p53 expression in skin was determined as p53 protein expression per 1000 cells (keratinocytes). The statistical analysis revealed that the expressions of p53 per 1000 cells were higher in non-sun-exposed lesional skin than the non-sun-exposed nonlesional skin, also in plaque-type psoriasis than guttate-type psoriasis (P = 0.000, P = 0.046, P = 0.037, respectively). There was a positive correlation between the p53 expression in non-sun-exposed lesional skin versus expression in sun-exposed lesional skin (cubic centimeters = 0.811, P = 0.027). Our results show a stronger association of elevated p53 expression with chronic rather than acute inflammatory psoriasis. This may indicate a mechanistic difference between plaque-type and guttate psoriasis. Alternatively, this could reflect a chronological course as the disease transitions from an acute to a chronic phase.

Examination of bcl-2 and p53 expressions and apoptotic index by TUNEL method in psoriasis

BACKGROUND

Psoriasis is characterised by hyperproliferation and by aberrant differentiation. Blockage of the normal apoptotic process is one of the factors implicated in the pathogenesis.

OBJECTIVE

To determine the apoptotic features by using TUNEL method and also bcl-2 and p53 expressions in psoriatic epidermis.

MATERIALS AND METHODS

Biopsies of 35 patients with psoriasis vulgaris and 14 normal skin were evaluated. Apoptotic cells were detected using the dUTP nick-end labelling assay; bc1-2 and p53 expressions were assessed by using immunohistochemical techniques. A semi-quantitative grading system (HSCORE) was used for comparison.

RESULTS

Bcl-2 was strongly expressed in basal keratinocytes of normal skin, while no expression was observed in 13 (37.2%) of the psoriatic samples and it was weakly expressed in the spinous cell layer of 22 (62.8%) samples. Moderate p53 expression was observed in the psoriasis group, while it was weak in the control. The percentage of TUNEL positive cells were significantly increased in the psoriasis group (65+/-2.30) when compared with the control (32.84+/-7.16).

CONCLUSION

Apoptotic index besides bc1-2 and p53 expressions in psoriasis differ from normal epidermis. Down-regulation of bc1-2 is consistent with the dynamics of psoriasis but increased TUNEL positive cells and p53 expression has not been fully elucidated yet. Gündüz K, Demireli P, Vatansever S, Inanir I. Examination of bcl-2 and p53 expressions and apoptotic index by TUNEL method in psoriasis.

Cell cycle regulating mechanisms in oral lichen planus: Molecular bases in epithelium predisposed to malignant transformation

OBJECTIVE

Expression of p53, p21, ki-67, Bcl-2 and caspase-3 proteins in oral lichen planus (OLP) was studied to investigate cell cycle regulation mechanisms in this disease.

MATERIAL AND METHODS

Oral biopsies were obtained from 51 patients with OLP and 26 controls for immunohistochemical analysis (peroxidase antiperoxidase) to quantify expression of the proteins under study (-: 0%, +: <10%, ++: 10-25%, +++: 26-50%, ++++: >50% positive cells).

RESULTS

Basal expression of caspase-3 was negative in 22 cases (46.8%) and positive in <10% of basal cells in 22 cases (46.8%); caspase-3 expression in inflammatory infiltrate was negative in 22 cases (46.8%) and positive in <10% of lymphocytes in 20 cases (42.5%). Basal expression of Bcl-2 was negative in 35 cases (74.5%); Bcl-2 was expressed in inflammatory infiltrate in 34 cases (72.3%) and was positive in <25% of lymphocytes in 14 of these (29.7%). Basal expression of p53 and p21 was positive in 32 (67.9%) and 23 (48.8%) cases, respectively. Basal expression of ki-67 was positive in 45 cases (95.7%), of which 20 (42.5%) showed positivity in >25% of cells; ki-67 was expressed in inflammatory infiltrate in 23 cases (48.9%). Significant associations were found between basal expressions of p53 and ki-67 (p<0.001) and between Bcl-2 expression in infiltrate and basal expression of ki-67 (p<0.001). No association was observed between basal expressions of p53 and caspase-3 (p=0.08). Bcl-2 expression in infiltrate and basal expression of ki-67 were independently associated with presence of OLP.

CONCLUSIONS

Epithelial cells in OLP do not preferentially develop apoptosis but rather cycle arrest or an increased proliferation rate, which may create a suitable substrate for malignant transformation.

The effects of calcipotriol and methylprednisolone aseponate on bcl-2, p53 and ki-67 expression in psoriasis

OBJECTIVE

The decrease of physiological apoptosis in the psoriatic lesions is thought to be involved in the pathogenesis of psoriasis, and induction of apoptosis was shown to contribute to the regression of psoriatic hyperplasia. In the present study, we compared the effects of calcipotriol and methylprednisolone aseponate (MPA) treatments on bcl-2, p53 and ki-67 expressions in psoriatic patients in order to define a relationship between regulation of apoptosis and healing process in psoriasis.

METHODS

Thirty psoriatic patients with stable and moderate chronic plaque psoriasis applied either calcipotriol or MPA ointment for 6 weeks twice daily. Evaluation of bcl-2, p53 and ki-67 positivity was performed at baseline and was repeated at sixth week for each therapy.

RESULTS

The mean percentage of positive keratinocytes was 8.63 +/- 7.15% for p53, 20.66 +/- 14.45% for ki-67, and 3.74 +/- 2.83% for bcl-2 in psoriatic skin at baseline. Normal skin values were 3.27 +/- 3.21% for p53, 4.93 +/- 4.77% for ki-67, and 1.80 +/- 0.41% for bcl-2. The psoriatic skin showed higher ki-67 (P < 0.05) and bcl-2 (P < 0.05) expression rates when compared to normal skin. The p53 positivity observed in psoriatic skin and normal skin was not significantly different (P > 0.05). Following calcipotriol and MPA treatments, there was a significant reduction in p53 and ki-67 positivity accompanied by an increase in bcl-2 positivity (P < 0.05 each). No significant differences were found at sixth week between calcipotriol and MPA groups with respect to p53, ki-67 and bcl-2 positivity (P > 0.05). The post-treatment psoriatic skin showed lower expression of p53, higher expressions of ki-67 and bcl-2 when compared to normal skin (P < 0.05 each).

CONCLUSION

The results of this study provide evidence that both calcipotriol and MPA decrease the p53 and ki-67 expression and increase bcl-2 expression. However, it should further be elucidated if these changes were the common behaviour of psoriatic keratinocytes to any antipsoriatic medication.

Analysis of p53 and bcl-2 protein expression in the non-tumorigenic, pretumorigenic, and tumorigenic keratinocytic hyperproliferative lesions

BACKGROUND

The hyperproliferative keratinocytic lesions encompass a wide range of non-tumorigenic, pretumorigenic, and tumorigenic conditions. The aim of this work was to examine the expression patterns of apoptosis-linked molecules (bcl-2 and p53) in these lesions.

METHODS

Immunoperoxidase staining methods were applied to analyze p53 and bcl-2 protein expression in a total of 66 cases, including 12 squamous cell carcinomas (both in situ and invasive SCC), 11 actinic keratoses (AK), 13 psoriasis vulgaris (PV), eight verruca vulgaris (VV), six chronic dermatitis (CD), five seborrheic keratosis (SK), four lichen planus (LP), three epidermodysplasia verruciformis (EDV), two condyloma acuminata (CA), two lichen simplex chronicus (LSC), and 10 specimens from normal skin.

RESULTS

As compared to normal skin (0.70 +/- 0.26), the bcl-2 average weighted scores in the non-tumorigenic (0.76 +/- 0.16), pretumorigenic (1.45 +/- 0.28), and tumorigenic lesions (2.83 +/- 0.50 and 2.92 +/- 0.50 for in situ and invasive SCC, respectively) showed significant up-regulation (p = 0.001). In the non-tumorigenic lesions, the bcl-2 expression values decreased in the following order: SK > EDV > CD > LP > CA > PV > VV (1.40 +/- 0.24 > 1.33 +/- 0.67 > 0.83 +/- 0.40 > 0.67 +/- 0.21 > 0.50 +/- 0.20 > 0.46 +/- 0.22 > 0.13 +/- 0.01, respectively). As compared to normal skin (1.10 +/- 0.23), the p53 average weighted scores in the non-tumorigenic (1.86 +/- 0.18), pretumorigenic (3.64 +/- 0.53), and tumorigenic lesions (5.00 +/- 1.00 and 5.08 +/- 0.86 for in situ and invasive SCC, respectively) showed significant up-regulation (p = 0.021). In the non-tumorigenic lesions, p53 average weighted scores decreased in the following order: SK > PV > CA > LP > CD > VV > EDV (3.20 +/- 0.49 > 2.38 +/- 0.27 > 2.0 +/- 0.0 > 1.83 +/- 0.48 > 1.0 +/- 0.37 > 1.0 +/- 0.33 > 1.0 +/- 0.0, respectively). There was a positive correlation between bcl-2 and p53 protein expression in normal skin (r = 0.966, p = 0.0001), non-tumorigenic (r = 0.775, p = 0.0001), pretumorigenic (r = 0.830, p = 0.001), and tumorigenic lesions (r = 0.757, p = 0.003).

CONCLUSIONS

Bcl-2 and p53 proteins are altered in the keratinocytic hyperproliferative lesions. Determination of whether these alterations reflect underlying gene mutations will require further investigations.

Irritated seborrheic keratosis of the external ear canal

Although a seborrheic keratosis is not rare on the skin of the trunk, extremities, head and neck of an elderly person, it is uncommon to originate in the external ear canal. Even rarer, an irritated subtype may arise in this location. We report the case of a 63-year-old man with an irritated seborrheic keratosis arising in the right external ear canal, who first presented with a bloody discharge from his right ear canal 3 years and 10 months before the subsequent operation. Macroscopically, a dome-like, black elevation was found at the anterior wall of the right external ear canal. A biopsy showed an exophytic papillomatous, hyperkeratotic growth of basaloid cells which revealed some nuclear atypism and mitosis. Squamous eddies and moderate inflammatory infiltrate were noted. Some cellular atypism made us suspect an irritated seborrheic keratosis. Because the patient hated the extirpation, he remained untreated for 3 years and 3 months following his first presentation. The biopsy and a surgical resection of his second presentation confirmed the diagnosis of irritated seborrheic keratosis. Immunohistochemical analysis of Ki-67, p53 and papillomavirus was performed to elucidate its character. We emphasize that irritated seborrheic keratosis does occur in the external ear canal and may cause some diagnostic difficulty. Pathologists should be aware of this fact and avoid overdiagnosis.

17Beta-hydroxysteroid dehydrogenase type 2: independent prognostic significance and evidence of estrogen protection in female patients with colon cancer

The mRNA expression of 17beta-hydroxysteroid dehydrogenase (17HSD) types 1 and 2 enzymes catalyzing opposite reaction of estrogen metabolism was investigated in colon cancer. Further, the significance of the 17HSD type 2 enzyme as a possible marker of colorectal cancer (CRC) prognosis was studied. In the normal mucosa, 17HSD type 2 mRNA was predominantly expressed in the surface epithelium and in the upper parts of the crypts. In the lamina propria expression was seen in endothelial cells and mononuclear phagocytes. In colorectal tumors, 17HSD type 2 expression was in most cases downregulated. Female patients had significantly more cancers with high 17HSD type 2 mRNA expression (n=11/35; 31%) than male patients (n=3/39; 8%) (P=0.02). We observed a significant impact of 17HSD type 2 mRNA expression on survival in female patients with distal colorectal cancer (n=24), with an overall cumulative 5-year survival rate of 54% in those with low 17HSD type 2 mRNA expression. None of the female patients with high 17HSD type 2 mRNA expression survived (n=11; P=0.0068; log rank 7.32). In male patients, no significant association with survival was observed. Our data provide evidence suggesting that low 17HSD type 2 mRNA expression is an independent marker of favorable prognosis in females with distal colorectal cancer, supporting the presence of gender- and location-related differences in the pathogenesis of colon cancer.

Low-grade vulvar and vaginal intraepithelial neoplasia: correlation of histologic features with human papillomavirus DNA detection and MIB-1 immunostaining

Histologic criteria of low-grade vulvar/vaginal intraepithelial neoplasia (VIN1/VAIN1) are well established; however, a significant interobserver variability in diagnosing VIN1/VAIN1 has been reported. The goal of this study was to evaluate the utility of MIB-1 immunostaining as an adjunct test to increase the diagnostic accuracy in equivocal cases of VIN1/VAIN1. The second goal was to examine the distribution of low- and high-oncogenic risk human papillomaviruses (HPVs) in VIN1/VAIN1 lesions. Consecutive vulvar/vaginal biopsies originally diagnosed as VIN1/VAIN1 (n = 43) or benign (n = 20) were reviewed by two pathologists to obtain a consensus diagnosis. The diagnosis was further confirmed with HPV testing using Short PCR Fragment 10 and Line Probe Assay. MIB-1 immunostaining was performed, and positive staining was defined as a cluster of two or more stained nuclei in the upper two thirds of the epithelial thickness. After verification of the diagnosis using the consensus histologic review and HPV detection as an objective confirmatory test, 31% of cases originally diagnosed as VIN1/VAIN1 were identified as being overdiagnosed. The sensitivity and the specificity of MIB-1 staining for identifying VIN1/VAIN1 were 0.96 and 0.90, respectively. Seventy percent of VIN1 cases were associated with low-risk viral types. In contrast, the majority (84%) of VAIN1 cases were associated with high-risk HPVs. In conclusion, MIB-1 staining is sensitive and specific for identifying VIN1/VAIN1, helpful in verifying the diagnosis in equivocal cases.

The effect of topical corticosteroids on Ki67 and p53 expression in vulval lichen sclerosus

BACKGROUND

Topical corticosteroids have become the treatment of choice for genital lichen sclerosus (LS) and are believed to be required for long-term relief of symptoms.

OBJECTIVE

To compare vulval LS that had been treated with topical corticosteroids, vulval LS that had not received topical corticosteroids, and histologically normal vulval skin.

METHODS

We used immunohistochemistry to look for Ki67 expression and abnormal p53 expression.

RESULTS

We found a statistically significant difference for p53 overexpression, with increased levels seen when comparing corticosteroid-treated LS with normal genital skin (P = 0.011). Ki67 expression was also significantly higher in the corticosteroid-treated group compared with normal genital skin (P = 0.001), and increased levels were also found in the treated group compared with untreated LS (P = 0.05).

CONCLUSIONS

Our data suggest that topical corticosteroids have an effect on cell cycle proteins in genital skin and, in particular, genital skin with LS changes.

p53 expression related to the aggressive infiltrative histopathological feature of basal cell carcinoma

AIMS

To determine whether the p53 protein expression which is involved in the genesis and progression of various malignant tumours may relate to age, sites or the aggressive histopathological feature of the basal cell carcinoma. METHODS ADN RESULTS: One hundred and fifty-eight basal cell carcinoma specimens from Songklanakarind Hospital, southern Thailand, collected from January 1992 to December 2000, were examined by immunohistochemistry using polyclonal anti-p53-CM1 (Novocastra Laboratories, Newcastle, UK; dilution 1:700). p53 protein expression was demonstrated in 48.7% of cases. The multivariate analysis showed that the aggressive infiltrative histopathological type was significantly associated with p53 expression (odds ratio 2.95, 95% confidence interval 1.10-7.90), whereas age, sun-exposure site, cellular response and fibrosis were not.

CONCLUSIONS

The p53 expression is found to be related to the aggressive histopathological feature, which may be of predictive value for the behaviour of basal cell carcinoma. However, this result does not support the relation between sun exposure inducing basal cell carcinoma and p53 protein expression.

Regulation of apoptosis by p53 in UV-irradiated human epidermis, psoriatic plaques and senescent keratinocytes

The carcinogenic effects of sunlight in human epidermis may be thwarted by either: transient growth arrest and repair of DNA photodamage in keratinocytes (KCs); elimination of KCs with damaged DNA via apoptosis; or by stimulating a senescence switch whereby KCs become irreversibly growth arrested. Using normal human skin organ cultures and living epidermal equivalents, we demonstrate that in the proliferative basal layer, removal of KCs via apoptosis had a rapid onset (beginning within 2 h) following UV-light exposure generating progressively greater numbers of KCs with thymine dimers as the dose of UV-light was increased; involved induction of Apaf-1, activation of caspase-3, and was dependent on p53 activation as addition of a p53 chemical inhibitor blocked the apoptotic response. Suprabasal layer KCs underwent apoptosis at much later time points (>8 h). KCs in the basal layer repaired DNA damage more rapidly than KCs in suprabasal layers. Steady state levels of p53 increased in irradiated cells, and the increase was accompanied by phosphorylation of serine 9 and serine 15, but not serine 6 residues. By contrast, cultured KCs undergoing spontaneous replicative senescence were resistant to UV-induced apoptosis. Senescent KCs constitutively contained low levels of p53, which were neither increased nor phosphorylated or acetylated after UV-exposure and possessed minimal DNA binding activity, indicative of functional inactivation. Furthermore, treatment of senescent KCs with DNA damaging agent adriamycin did not result in activation of latent p53 or apoptosis. When KCs within psoriatic plaques were examined, they resembled senescent KCs in that they expressed p53, which was not phosphorylated or acetylated. Thus, UV-light induces DNA damage in human epidermal KCs triggering p53 activation, and subsequent apoptosis involving distinct cell layers and kinetics. However, the lack of p53 activation as seen in senescent KCs and psoriatic plaques, is associated with a relative resistance of KCs to UV-induced apoptosis. In conclusion, the sensitivity and resistance of KCs to apoptosis depends not only on the location within various layers of epidermis and levels of p53, but may also involve p53 activation via post-translational modifications.

Downregulation of estrogen-metabolizing 17 beta-hydroxysteroid dehydrogenase type 2 expression correlates inversely with Ki67 proliferation marker in colon-cancer development

The 17HSDs are a group of isozymes that catalyze the interconversion between high-activity 17 beta-hydroxysteroids and low-activity 17-ketosteroids. In the present study, we characterized the expression of 17HSD types 1 and 2 in normal and malignant gastrointestinal tissues and cells. Using the colon as a model for cancer of the gastrointestinal tract, expression of the 17HSD enzymes in cancer development was studied and correlated with proliferation and differentiation markers as assessed by Ki67 and mucin staining, respectively. In normal colon and small intestine, 17HSD type 2 mRNA was expressed in the surface epithelial cells and, to a lesser extent, in the cryptal epithelial cells. In colon-cancer specimens, 17HSD type 2 expression was downregulated both in the tissues and in the cell lines and correlated inversely with the proliferation marker. No expression for the 17HSD type 1 enzyme was observed in normal or cancerous gastrointestinal tract tissues. In line with the expression studies, 17HSD activity measurements with colon cells showed that only the oxidative conversion of E2 to E1 was present, and Northern blot analysis showed the signal only for 17HSD type 2. Localization of the ERs alpha and beta, assessed by immunohistochemistry and in situ hybridization, showed the presence of ER beta in the lamina propria of the colon. Our study shows that 17HSD type 2 expression is associated with the functional integrity of the gastrointestinal tract. The decrease in expression of the type 2 enzyme may increase estrogen influence in colon cancer.

Switch from p53 to MDM2 as differentiating human keratinocytes lose their proliferative potential and increase in cellular size

p53 transcription factor is mutated in most skin cell carcinomas and in more than 50% of all human malignancies. One of its transcriptional targets is MDM2, which in turn down-regulates p53. The role of the p53/MDM2 regulatory loop upon genotoxic stress is well documented, but less is known about its role in normal tissue homeostasis. We have explored this pathway during the different transitions of the human epidermal differentiation programme and after isolating stem cells, transit amplifying cells or differentiating cells from epidermis. Maximum expression of p53 was found in proliferating keratinocytes. A striking and transient induction of MDM2 and a down-modulation of p53 characterized the transition from proliferation to differentiation in primary human keratinocytes. These changes were delayed in late differentiating carcinoma cells, and were clearly different in suspended primary fibroblasts. Interestingly, these changes correlated with an increase in cell size, at the time of irreversible commitment to differentiation. Induction of MDM2 was also associated with suppression of proliferation in normal, or hyperproliferative, psoriatic epidermis. Moreover, both proteins were induced as keratinocytes were driven to leave the stem cell compartment by c-Myc activation. Overall, our results show a critical regulation of the p53/MDM2 pathway at the epidermal transition from proliferation to differentiation.

Initiation of rapid, P53-dependent growth arrest in cultured human skin fibroblasts by reactive chlorine species

Oxidants produced by neutrophils have been implicated in causing cancers associated with chronic inflammation. Hypochlorous acid is the most potent oxidant produced by these cells in appreciable amounts. It reacts with amines to form chloramines, which are weaker oxidants but are mutagenic. Recently, we showed that sublethal doses of hypochlorous acid increased levels of the transcription factor protein 53 (p53) and the wild-type activating fragment-1/cyclin-dependent kinase inhibitory protein-1 (WAF1/CIP1) in cultured human skin fibroblasts. WAF1/CIP1 is an important intermediate in the pathway leading to growth arrest. We now show that low doses of hypochlorous acid and physiological chloramines lead to an inhibition of both DNA synthesis and division of cultured human skin fibroblasts. Inhibition of DNA synthesis occurred within 1 h of hypochlorous acid treatment, was maintained for 24 h, and returned to a normal rate after 48 h. Cell division was inhibited by hypochlorous acid and chloramines for 48 h and returned to normal 72 h after treatment. Growth arrest was dependent on p53 because it was blocked when cells were transfected with a p53-binding oligonucleotide. We propose that reactive chlorine species will initiate WAF1/CIP1-dependent growth arrest that will counteract their mutagenic effects and minimize the possibility of the malignant transformation of cells surrounding sites of inflammation.

Oxidative stress in keratinocytes as an etiopathogenetic factor of psoriasis

A new etiopathogenetic concept of psoriasis is proposed, which considers psoriasis as a typical inflammatory process characterized by increased antioxidant activity and overexpression of apoptotic receptors. Under these conditions, hyperstimulation of germinative layer cells proliferation dramatically accelerates keratinocyte passage towards apoptotic effect of atmospheric oxygen and its reactive species dooming to death cells with enhanced expression of apoptotic receptors. Oxidative stress of nondifferentiated keratinocytes triggers the formation of defective horny layer, the key mechanism of psoriasis.

Evaluation of p53, PCNA, Ki-67, MDM2 and AgNOR in oral peripheral and central giant cell lesions

OBJECTIVES

Peripheral giant cell lesion (PGCL) and central giant cell lesion (CGCL) of the jaws have a distinct clinical behaviour. Whether such biological differences are supported by a distinct pattern of proliferation markers or cell cycle associated proteins expression is not known. Therefore the purpose of the present study was to compare the immunohistochemical expression of p53, MDM2, Ki-67, PCNA and the histochemical expression of argyrophilic nuclear organiser region (AgNOR) on PGCL and CGCL of the jaws.

MATERIALS AND METHODS

Paraffin wax blocks of 14 cases of PGCL and 12 cases of CGCL were retrieved. A biotin-streptavidin amplified system was used for identification of the antigens. The AgNOR number was also evaluated.

RESULTS

Ki-67 immunoreactivity was greater in the mononuclear cells of PGCL compared to CGCL. PCNA and AgNOR staining were similar in PGCL and CGCL. Prominent MDM2 immunoreactivity was observed in all tissues investigated. By contrast, there was no p53 immunoreactivity.

CONCLUSIONS

Although CGCL present a more aggressive clinical behaviour, it has a decreased proliferative activity compared to PGCL. Finally, p53, MDM2, PCNA, Ki-67 immunohistochemical expression and AgNOR histochemical expression do not reflect their distinct biological behaviour.

Apoptosis and p53 protein expression increase in the process of burn wound healing in guinea-pig skin

Apoptosis and the expression of p53 protein, an apoptosis-related protein, in the process of healing of a full-thickness burn wound in guinea-pig skin were studied with the terminal deoxynucleotide transferase nick-end labelling method, electron microscopy, and immunohistochemistry, respectively. Apoptosis was detected in the peripheral zone of heat-injured skin from 12 h until day 10 after the burn, with the peak occurring on day 2. The peripheral zone of heat-injured skin showed p53 protein from 12 h through day 2, with the peak occurring on day 2. Apoptosis was also detected in tissues regenerated for covering skin defects. The peak of apoptosis in the regenerated epidermis occurred at days 7-10, when the epidermis was most acanthotic. p53 protein reactivity was also detected in the acanthotic regenerated epidermis, with a peak on day 7. The peak of apoptosis in the granulation and scar tissue took place from day 10 to 14, when the granulation tissue started diminishing, but p53 protein reactivity was not detected there. These findings suggest that apoptosis plays an important part in the elimination of dying and/or dead cells resulting from heat stress, the terminal differentiation of the regenerated epidermis, and the decrease in cellularity during remodelling. The apoptotic process during remodelling may be mediated by some p53-independent pathway.

Differential expression of p53 and Ki-67 proteins in classic and iatrogenic Kaposi's sarcoma

In many neoplasms, the finding p53 immunoreactivity correlates with striking cytologic atypia, a high tumor cell proliferation rate, and poor prognosis. The literature regarding p53 and Ki-67 (a nuclear proliferation-associated antigen) immunoreactivity in Kaposi's sarcoma is limited. We aimed to: (1) evaluate the role of p53 in the development of Kaposi's sarcoma; (2) determine whether there is a correlation between p53 and Ki-67 protein expression; and (3) determine possible differences between classical Kaposi's sarcoma, known usually to have a benign course, and iatrogenic Kaposi's sarcoma, the course of which is unpredictable, by studying the differential expression of p53 and Ki-67. Among 26 cases of classic KS and 19 of iatrogenic KS, 12 were classified histopathologically as early type and 33 as mixed or spindle-cell type. P53 and Ki-67 immunoreactivity correlated significantly with the histopathologic stage of KS (r=0.63, p=0.0001; r=0.42, p=0.0084, respectively). P53 was not detected in any of the cases in an early histopathologic stage but was present in 55% of the cases in a more advanced stage. The spindle cells increased in proportion with the histopathologic progression and were more often positive (p=0.019) and displayed more extensive staining than the endothelial cells (p=0.0001). There was a strong positive correlation between p53 and Ki-67 protein expression (r=0.43, p=0.0087). There was no correlation between the expression of either p53 or Ki-67 and the extent of the eruption. The expression of p53 and Ki-67 was significantly lower in iatrogenic cases than in the classic cases (p=0.009, p=0.0014, respectively), although no statistical difference was found between the histopathologic stages in the two clinical forms of KS. P53 immunoreactivity was detected in 79% of the cases of classic Kaposi's sarcoma in the mixed or spindle cell stage but in only 21.5% of the iatrogenic cases showing the same histopathologic stage (p=0.001), and the percentage of spindle cells as well as the endothelial cells expressing p53 was higher in the classic cases than in the iatrogenic cases (p=0.0032, p=0.0142, respectively). We conclude that p53 immunoexpression is a marker of tumor progression in classic Kaposi's sarcoma but not in most cases of iatrogenic Kaposi's sarcoma. The proliferative activity of the tumor cells in classic Kaposi's sarcoma is much higher than in iatrogenic Kaposi's sarcoma. Our work implies that the molecular steps involved in classic and iatrogenic Kaposi's sarcoma differ.

Pigmented human skin equivalent--as a model of the mechanisms of control of cell-cell and cell-matrix interactions

The melanin pigment system in human skin is extraordinarly well developed and assures the photoprotection of the skin against harmful solar radiation. Specific cell-cell interactions between one melanocytes and keratinocytes play a fundamental role in the regulation of melanogenesis and melanin pigementation, the two key elements of this system, giving rise to the concept of a structural, functional collaborative 'epidermal melanin unit,' Early experiments strongly suggested that melanocyte growth and differentiation are regulated by paracrine factors from keratinocytes and other skin cells. In addition, co-culture studies with keratinocytes has shown that the extracellular matrix acts as a local environmental signal for dendrite formation and melanogenesis. Attempts to reconstruct pigmented human skin in vitro have made great progress over the last decade. The behavior of cells in these pigmented human skin equivalents closely resembles that in vivo, and the cells can still respond to appropriate extrinsic regulatory stimuli such as ultraviolet radiation. Keratinocytes and fibroblasts have been shown to be active partners in the regulation of melanocyte distribution, viability and other differentiation functions, presumably by direct contact and the effects of various soluble paracrine factors. By reproducing cell-cell and cell-matrix interactions, these culture systems provide a promising experimental model for investigating regulation of the skin pigmentary system and the role of photoprotection against harmful solar radiation.

Hypochlorous acid activates the tumor suppressor protein p53 in cultured human skin fibroblasts

The carcinogenicity associated with chronic inflammation has been attributed to neutrophils and the oxidants they produce. Neutrophils accumulate at sites of chronic inflammation, where they are stimulated to produce hydrogen peroxide which is converted to hypochlorous acid by coreleased myeloperoxidase. We report here that levels of the tumor suppressor protein p53 were increased in cultured human skin fibroblasts that had been incubated with stimulated neutrophils. The increase in p53 required the myeloperoxidase-dependent generation of hypochlorous acid and could be mimicked by exposing cells to a flux of hypochlorous acid produced by purified myeloperoxidase and a hydrogen peroxide-generating system. Levels of p53 were very sensitive to hypochlorous acid, with fluxes as low as 0.2 microM per min being effective. Levels of the p53-dependent protein WAF1/CIP1 were also elevated when fibroblasts were treated with hypochlorous acid. This result indicates that the p53 in the cells treated with hypochlorous acid was transcriptionally active. Hydrogen peroxide alone also elevated p53 and WAF1/CIP1, but the fluxes required were nearly 10-fold higher than those that were effective for hypochlorous acid. Our results implicate hypochlorous acid in the neutrophil-dependent initiation of a signal transduction pathway which could minimize the carcinogenicity of chronic inflammation.

An immunohistochemical study of p53 and PCNA in inflammatory papillary hyperplasia of the palate: a dilemma of interpretation

OBJECTIVE

Inflammatory papillary hyperplasia of the palate (IPHP) or the granular type of denture stomatitis, is a non-neoplastic lesion characterized histologically by a significant epithelial hyperplasia and inflammatory infiltrate usually caused by trauma and Candida infection. p53 and proliferative cell nuclear antigen (PCNA) are cell-cycle regulators, that when overexpressed, are considered by many investigators as markers of malignant transformation. The objective of this study was to investigate the immunodetection of p53 and PCNA in IPHP, and to correlate these results with the degree of epithelial hyperplasia and inflammatory infiltrate.

MATERIALS AND METHODS

In 12 cases diagnosed clinically as IPHP, Candida was cultured from the denture base and the palatal mucosa. Lesions were biopsied and stained with H&E for histomorphometric analysis of the epithelial width and inflammatory infiltrate. PAS and Gram stains were used for screening of Candida. Sections were immunostained with DO-7 for p53 and PC-10 for PCNA. Fifteen palatal biopsies obtained from autopsies of edentulous subjects with normal palatal mucosa served as controls.

RESULTS

All cultures of swabs from both the palatal mucosa and denture base were positive for Candida. Candidal hyphae could not be identified in PAS stained sections. Small foci of Gram-positive organisms were found in two cases of IPHP. Epithelial width and inflammation were significantly higher in IPHP than in controls (P < 0.001). A three-fold increase in positively stained cells for p53 and a two-fold increase in positively stained cells for PCNA were seen in IPHP compared with controls (P < 0.001).

CONCLUSIONS

Although a significant increase in the immunodetection of p53 and PCNA may indicate a malignant potential, IPHP has never been reported to undergo malignant transformation nor is it associated with cytologic signs of dysplasia. The increase in the epithelial width and inflammation degree is probably associated with the colonization of the denture bases with Candida organisms. The increased detection of p53 and PCNA can be a secondary effect of cytokines originating from both the inflammatory cells and the keratinocytes. Thus, immunodetection of p53 and PCNA by current immunohistochemical methods on archival tissues is neither specific nor sensitive enough to be used as indicators for malignant potential in the absence of cytological dysplastic changes or genetic proof of mutated cell cycle genes.

Vulvar lichen sclerosus and squamous cell carcinoma: a cohort, case control, and investigational study with historical perspective; implications for chronic inflammation and sclerosis in the development of neoplasia

The histological changes of lichen sclerosus (LS) are frequently found in association with vulvar squamous cell carcinoma (SCC). The importance of chronic inflammation and scarring in oncogenesis is well recognized. Thirty-two patients with symptomatic vulvar LS and 60 with vulvar SCC were studied. Paraffin sections of vulvar LS, and three controls groups (acute scars, normal vulva, and vulvar lichen simplex chronicus [LSC]) were investigated with a panel of seven tissue markers and for DNA content in areas without vulvar intraepithelial neoplasia (VIN). All published cases to date of vulvar LS associated with SCC were reviewed. Of the cohort of symptomatic vulvar LS patients (mean/median age, 60 years), 9% developed VIN lesions and 21% invasive SCC; symptomatic LS preceded the carcinoma by a mean of 4 years (range, 1 to 23 years). Second and third primary tumors developed in three of these patients. Of the series of 60 patients presenting with vulvar SCCa, the clinical setting and histological features of SCCs associated with LS were significantly distinctive compared with SCCas without LS: SCCs associated with LS occurred in an older age-group (74 v 65 years; P = .01), were located on the clitoris (41% v 5%; P = .003), were of conventional SCCa type (85% v 57%; P = .02), were associated with a prominent fibromyxoid stromal response (46% v 10%; P = .004), were not associated with VIN 3 (SCC in situ) (5% v 67%; P = .02) and diffusely expressed tumor suppressor gene product p53 (43% v 19%; P = .01) and cytokine TGF-beta (33% v 9%; P = .05). The epidermis of vulvar LS was similar to that of acute scars and differed significantly compared with normal vulva with respect to keratinocytic expression of markers to keratin AE 1, involucrin and filaggrin, epidermal thickness (0.13 mm [LS] v 0.05 mm [normal]; P < .03), and proliferative index by PCNA and Mib-1 labeling (53/60 [LS] v 15/19 [normal] per 200 basal cells [bc]; P < .003). Vulvar LS showed significantly higher expression of p53 than all three control groups (80 [LS] v 3 [normal]/44 [acute scar]/28 [LSC] per 200 bc; P < .008), and aneuploidy (33% v diploid controls) in the absence of VIN. Comparing LS with and without associated SCCa found significant increases in age of patients (74 v 66 years; P = .001), and DNA aneuploidy (52% v 11%; P = .0001) and no differences in epidermal thickness, sclerotic thickness, proliferative index, or p53 expression. However, those cases of LS with an aneuploid DNA content showed significantly elevated p53 expression (88 v 60/200 bc; P = .01) and epidermal thickness (0.16 v 0.11 mm; P = .005) compared with LS with a diploid DNA content. Review of published cases supports an association between LS and vulvar SCC. The phenomenon of chronic inflammation and scarring giving rise to carcinoma has been well documented. Vulvar lichen sclerosus (LS) is an inflammatory dermatosis characterized by clinicopathologic persistence and hypocellular fibrosis (sclerosis). A subset of vulvar SCCs is significantly associated with the presence of LS and diffusely express the p53 gene product. Keratinocytes affected by LS show a proliferative phenotype and can exhibit markers of neoplastic progression such as increased p53 expression and DNA aneuploidy. As a chronic scarring inflammatory dermatosis, vulvar LS could act as both "initiator and promoter" of carcinogenesis, explaining the frequent coexistence of these diseases. Because keratinocytes of LS significantly express tumor suppressor gene p53 protein, the p53 gene may be involved early in this proposed pathway of carcinogenesis.

An overview of the complexities and subtleties of immunohistochemistry

Immunohistochemistry has the potential to be a powerful research tool. However, immunohistochemical studies are frequently undertaken without regard to the complexities and subtleties of these useful techniques. This review aims to address the problems and limitations that are often encountered, and the procedures that should be considered in both the planning and interpretation of immunohistochemical studies. Particular reference is made to the generation of functionally different protein isoforms from a single gene by alternative splicing and post-translational modifications, primary antibody selection, the effects of tissue manipulation such as fixation and antigen retrieval, the need for appropriate controls and interpretation of staining patterns.

Absence of p53 mutations in benign and pre-malignant male genital lesions with over-expressed p53 protein

Mutations of the tumor-suppressor gene p53 are common in epithelial tumors. Clonal mutations of p53 have been found in cervical and vulvar carcinomas negative for human papillomavirus (HPV), though at least in cervical cancer HPV infection and p53 mutations are not mutually exclusive. We have previously shown that about 40% of male genital warts and bowenoid papulosis lesions exhibit immunohistochemically detectable aberrant p53 protein, irrespective of the presence of HPV DNA. We studied p53 mutations in exons 4-8 with SSCP and sequencing in 13 male patients with 1 to 3 therapy-resistant genital warts or intra-epithelial neoplasias each and in 4 patients with penile squamous cell carcinoma. Thus, 13 genital warts, 6 bowenoid papulosis, 1 Queyrat's erythroplasia and 1 carcinoma in situ were studied. p53 protein was detected immunohistochemically, and HPV status was analyzed with DNA in situ hybridization and amplification of HPV-specific DNA. There was no correlation between p53 protein expression and HPV status. No mutations in exons 5-8 of the p53 gene were found in any of the lesions, and furthermore, no exon 4 mutations were found in lesions positive in p53 immunohistochemistry. In conclusion, overexpression of p53 does not indicate a p53 mutation in male genital warts, pre-malignant lesions or malignant squamous cell carcinomas. Our study thus suggests that p53 mutations are not important, or at least not early, events in male genital carcinogenesis.

Apoptosis in the pathogenesis of cutaneous lupus erythematosus

Defective regulation of apoptosis may play a role in the development of autoimmune diseases such as systemic lupus erythematosus, in which the skin is a prominent target. To our knowledge, however, the nature of epidermal changes in cutaneous lupus erythematosus (LE) has not previously been investigated. We investigated the involvement of apoptosis in cutaneous LE. A total of 44 lesional skin samples from patients with cutaneous LE, 44 skin samples from patients with scleroderma, five skin specimens from patients suffering from dermatomyositis, and 13 normal skin samples were stained immunohistochemically with monoclonal antibodies to Ki-67, p53 (DO-7), and bcl-2. The lesional skin from cutaneous LE, except LE profundus, showed a marked increase in Ki-67- and p53-positive keratinocytes, which were predominantly located in the basal layer of the epidermis and follicle, and a drastic reduction in the number of bcl-2-positive cells localized in the basal cell compartment. With TdT-mediated dUTP-biotin nick end-labeling staining, we demonstrated that extensive apoptosis occurred in almost the whole epidermis of cutaneous LE, except in cases of LE profundus. This abnormal expression of Ki-67, p53, and bcl-2 and the occurrence of apoptosis in the epidermis was also observed in epidermis from patients with dermatomyositis, but not in that from patients with scleroderma.

Immunohistochemical nuclear staining for p53, PCNA, and Ki-67 in different histologic variants of basal cell carcinoma

BACKGROUND

Increased expression of p53 has been found in the majority of basal cell carcinomas (BCCs); however, UV-light-induced signature mutations are present in only about 50% of cases. Increased nuclear staining with an immunohistochemical marker of proliferation, proliferating cell nuclear antigen (PCNA), has been correlated with aggressive behavior in BCC.

OBJECTIVE

Our purpose was to determine whether there is any relationship between different histologic variants of BCC and their expression of p53, PCNA, and Ki-67.

METHODS

We used immunohistochemical stains for p53, PCNA, and Ki-67, in superficial-multicentric, nodular-noduloulcerative, sclerosing, infiltrative, and metatypical BCC, to determine whether the staining patterns differ in these different histologic variants of BCC.

RESULTS

Superficial-multicentric BCCs were negative for p53 in four of eight tumors. Nodular BCC showed moderately intense p53 nuclear staining with some peripheral accentuation. PCNA nuclear staining was greater than Ki-67, and PCNA-positive cells were fewer than 10% in nodular BCC. Sclerosing and infiltrative BCC showed intense p53 nuclear staining with peripheral accentuation. PCNA nuclear staining was greater than Ki-67, and PCNA-positive cells were greater than 30% in the majority of these tumors. Metatypical BCCs showed diffuse intense p53 staining. PCNA nuclear staining was greater than Ki-67, and PCNA-positive cells were greater than 30% in all tumors studied. When overlying actinic keratoses showed p53 staining, the staining did not necessarily correlate with the intensity or even the presence of positive staining in the subjacent BCC.

CONCLUSION

There are at least four distinctive patterns for staining of p53, PCNA, and Ki-67 that correlate with different histologic variants of BCC.

Apoptosis-associated markers in oral lichen planus

Hypothesizing that loss of basal cells in oral lichen planus is due to apoptosis, we evaluated LP specimens for apoptosis-regulating proteins [positive regulators Bcl-xS, Bax, Fas/Fas-ligand, p53, and negative regulators (anti-apoptotic) Bcl-2, Bcl-xL and compared results with reactions in normal mucosa and chronically inflamed gingiva. Also, sections were evaluated with an in situ TUNEL assay that identifies apoptotic DNA fragments. Basal keratinocytes in normal buccal mucosa, nonspecific gingivitis, and LP were negative for Bcl-2 protein, but melanocytes and lymphoid cells were positive. Keratinocyte staining for Bcl-x was negative to weak in normal buccal mucosa and gingivitis, and moderate in LP. Keratinocytes (especially upper prickle cells) in all tissues stained similarly for Bax at weak to moderate levels. Also, no differences in Fas and Fas-ligand staining were evident. Prominent p53-positive staining was seen in all LP biopsies (10-100% of basal keratinocytes) but not in normal buccal mucosa and gingivitis. Few basal keratinocytes in 5/10 LP cases exhibited a positive in situ signal for DNA fragment-associated apoptosis. That the Bcl-2 family of proteins and Fas/Fas-ligand were detected in normal and diseased tissues, and were occasionally expressed differently in oral LP, supports the notion that apoptosis is a potential mechanism of keratinocyte loss, especially in LP. The pattern of p53 staining in oral LP suggests over-expression of wild-type protein; a phenomenon that would arrest the cell cycle to allow repair of damaged DNA, or trigger apoptosis. While immunohistochemical evidence for apoptosis-associated basal keratinocyte death in LP was slight, it appeared that it may be p53 protein, and possibly Bcl-x associated.

Evaluation of cross-reacting anti-human antibodies in the euthymic hairless guinea pig model (HGP) suggests that the HGP may be a model for the study of proliferative skin disease

Animal models have an important role in cutaneous research. The guinea pig has proven to be a useful model in a wide spectrum of these cutaneous studies; however, its usefulness is often compromised by the need for depilation. A euthymic hairless guinea pig (HGP) model avoids the problems associated with depilation. Morphologically, as in human skin, these animals have a multi-cell-layer epidermis. Proliferation kinetic studies, as well as documentation of the degree of immunologic cross-reactivity between available antibodies to human cutaneous antigens, could extend the usefulness of this animal model. We performed a battery of anti-human antibodies on formalin fixed tissue, to a variety of antigens present within the skin and on inflammatory cells. These included CD3, UCHL-1, OPD4, L-26, KP-1, Factor XIIIa, S-100 protein, cytokeratin (AE1, AE3 and CK1), CAM 5.2, vimentin, CD 34, Factor VIII, fibronectin, SM actin, collagen IV, laminin, Bcl-2, p53, Ki-67, and PCNA. Cross-reacting antibodies included: CD3, S-100 protein, cytokeratin (AE1, AE3 and CK1), vimentin, Factor VIII, SM actin, collagen IV, p53, Ki-67, and PCNA. Although this battery of antibodies is limited, the markedly increased staining of Ki-67 and PCNA within keratinocytes in the epidermis as compared to normal human skin reflects a high proliferative rate. In addition, positive staining for p53, Ki-67, and PCNA may be useful in studying effects on cell cycle kinetics and apoptosis.

In situ characterization of inflammatory responses in the rectal mucosae of patients with shigellosis

Shigella species cause bacillary dysentery in humans by invading epithelial cells of the colonic mucosa leading to colonic epithelial cell destruction and inflammation. For further analysis of local gut inflammation, morphological changes and the potential involvement of mediators in regulatory mechanisms of cell activation and cell proliferation were studied immunohistochemically in rectal mucosal biopsies taken from patients during the acute phase of shigellosis and at convalescence. Rectal biopsies from 25 Shigella dysenteriae-1 and 10 Shigella flexneri-infected patients and from 40 controls were studied. The frequencies of proliferative cells (Ki67-positive cells), p53-immunostaining cells, and cells coexpressing Ki67 with CD3 or with p53 were analyzed. Immunostaining for the inducible nitric oxide synthase (iNOS) and the endothelial NOS was assessed. In addition, the frequencies of apoptotic cells and CD68+ cells that engulf apoptotic cells were assessed. By morphological grading, 20% of the patients had advanced inflammation (grade 3) in the acute phase; mild inflammation (grade 1) was seen in 37% of the patients at convalescence as well as in 10% of the controls. The findings in the present study suggest that in the acute phase of shigellosis inflammation is characterized by increased cell turnover in the lamina propria (LP) and the epithelium, increased iNOS expression in the surface epithelium, and apoptosis, which seems to be associated with LP macrophages. The findings also suggest that neither p53 nor iNOS are important factors for the induction of apoptosis in shigellosis. Expression of p53 may be related to early cell activation in crypt epithelium. Moreover, there is an indication of an active, low-level inflammatory process at convalescence. The results thus indicate that Shigella-induced inflammation is associated with a complex series of cellular reactions in the rectal gut mucosa which persist long after clinical symptoms have resolved.

Apoptosis in oral erythema multiforme

OBJECTIVE

Cell death was evaluated in oral erythema multiforme to test the hypothesis that apoptosis may be a mechanism by which keratinocytes die in this condition.

STUDY DESIGN

Ten erythema multiforme and five control oral mucosa biopsy specimens were evaluated in immunohistochemically stained sections for apoptosis-regulating proteins Bcl-2, Bcl-x, Bax, p53, Fas, and Fas-ligand. Apoptotic keratinocytes, determined by a detection method for DNA fragmentation (TUNEL) and by conventional morphologic criteria were counted per high power field.

RESULTS

Keratinocyte staining for Bcl-2 protein was comparable in erythema multiforme and controls. Bcl-x expression was reduced in five erythema multiforme cases. Staining for Bax protein differed in six erythema multiforme cases and showed variable intensity in layers under the parakeratin. Only slight differences in staining patterns of Fas and Fas-ligand proteins were noted between erythema multiforme and controls. The number of apoptotic keratinocytes evaluated by morphologic examination was significantly higher in erythema multiforme (mean per high power field, 0.90 +/- 0.2; controls, 0.06 +/- 0.04; p < 0.05, Mann-Whitney test) and was limited in significance by the TUNEL method (erythema multiforme, 0.43 +/- 0.1; controls, 0.02 +/- 0.02). Overexpression of p53 protein was seen in basal keratinocytes in five erythema multiforme specimens (mean, 17.5 +/- 4.03 per high power field; controls 1.2 +/- 0.3).

CONCLUSIONS

There is evidence that cell death in erythema multiforme is at least in part due to apoptosis. The apoptotic mechanism may be related to an altered expression of apoptosis-regulating proteins. Although measurable alterations in the phenotypic expression of Fas and Fas-ligand proteins were not apparent, activation of Fas/Fas-ligand system could still be involved in the induction of apoptosis in erythema multiforme.