Immunohistochemical study of cyclooxygenase-2 and p53 expression in skin tumors

Overexpression of cyclooxygenase-2 (COX-2) has been demonstrated in various cancers, including experimentally promoted tumors, gastrointestinal cancers, breast tumors and skin tumors. The mechanism that controls COX-2 expression is not yet clear. Currently, it is reported that COX-2 expression is frequently associated with mutated p53 genes. The goal of this study was to evaluate the expression patterns of COX-2 and p53 in several skin tumors and their correlation. An immunohistochemical method was used to investigate the expression of COX-2 and p53 proteins on formalin-fixed, paraffin-embedded tissue specimens of squamous cell carcinomas (SCC), basal cell carcinomas (BCC), Bowen's disease (BD), actinic keratosis (AK) and porokeratosis. The expression of COX-2 increased in 50% (5/10) of SCC, 80% (8/10) of BCC, 40% (4/10) of BD, 50% (5/10) of AK, and 20% (2/10) of porokeratosis cases. The expression of p53 increased in 90% (9/10) of SCC, 70% (7/10) of BCC, 70% (7/10) of BD, 50% (5/10) of AK, and 40% (4/10) of porokeratosis cases. COX-2 positivity rates of the p53-positive skin tumors were 56%, 100%, 57%, 80% and 25% in SCC, BCC, BD, AK and porokeratosis, respectively. However, the correlation between p53 and COX-2 expression in skin tumors was not statistically significant (P > 0.05). Our results indicate that skin COX-2 and p53 may play roles in skin tumors, but that there is no apparent correlation between the two markers.

Gene expression profiling of porokeratosis demonstrates similarities with psoriasis

BACKGROUND

Porokeratosis (PK) is a clinically heterogeneous entity associated with sharply demarcated, annular, or serpiginous lesions with a hyperkeratotic ridge. This disorder is associated with aberrant keratinocyte differentiation that histologically manifests as a stack of parakeratin termed the cornoid lamella; this structure represents the peripheral hyperkeratotic ridge of clinical lesions. Histologically, the keratinocytes forming the cornoid lamella demonstrate an altered differentiation program. However, the molecular basis of PK remains incompletely understood.

METHODS

As a first step in characterizing PK at the molecular level, gene expression profiling was performed on a cornoid lamella isolated from a large, Mibelli-type porokeratotic lesion. As a control, gene expression profiling of peripheral uninvolved epidermis was also performed. The gene expression profile of cornoid lamellar keratinocytes was compared with similar profiles obtained from a psoriatic plaque and cutaneous squamous cell carcinoma.

RESULTS

Our study demonstrates a striking similarity between the gene expression profiles of PK and psoriasis. In addition, novel markers of the porokeratotic keratinocytes were identified, including keratin 16, S-100 A8 and A9, and connexin 26.

CONCLUSIONS

This study supports the hypothesis that PK is a disorder of hyperproliferative keratinocytes exhibiting similarity at the molecular level to psoriasis. Consequently, some therapeutic modalities efficacious for psoriasis may be of benefit in PK.

p53 alterations in porokeratosis

BACKGROUND

Porokeratosis (PK) is a group of cutaneous entities characterized by disordered epidermal keratinization and by a predisposition to develop malignant transformation. The molecular mechanism of this carcinogenesis remains unclear, but p53 has been proposed as a mediator of this process. p53 overexpression, detected by immunohistochemistry, has frequently been reported in PK, and p53 mutations are direct results of ultraviolet (UV) skin exposure and are directly involved in most common skin cancers.

METHODS

Eleven cases of Mibelli-type PK, one of them associated with a squamous cell carcinoma, were reviewed. Formalin-fixed, paraffin-embedded archival tissue from these cases was immunostained for p53 and used for DNA extraction for the analysis of p53 mutations by polymerase chain reaction and single-strand conformation polymorphism.

RESULTS

Increased p53 expression was confirmed in all cases. Most of them showed a discontinuous labeling, often stronger at the base of the cornoid lamella. No relation with sun exposure was observed. Finally, no p53 mutations were found at the gene levels more frequently damaged in human cancers called "hot spots".

CONCLUSIONS

p53 alterations can be involved in the pathogenesis of the PK and the carcinogenesis arising in some of the lesions. Since p53 gene inactivation in human cancer is related to mutation and/or loss, the absence of genetic damage could indicate that p53 alterations are only at the protein level, leading to an abnormal cell-cycle control. UV exposure does not seem to play a main role in the process.

Premature apoptosis of keratinocytes and the dysregulation of keratinization in porokeratosis

BACKGROUND

Porokeratosis is a dyskeratotic disorder of the skin characterized by cornoid lamella with parakeratosis, hyperkeratosis and loss of granular layers. The pathogenesis of porokeratosis and the mechanism(s) of its abnormal keratinization are still unknown.

OBJECTIVE

To elucidate the mechanism(s) of abnormal keratinization that leads to the formation of cornoid lamellae in porokeratosis.

METHODS

Apoptosis of keratinocytes was assessed in the skin of seven patients by an in situ apoptosis assay based on the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL) reaction. Patterns of loricrin and involucrin expression were examined by immunohistochemistry.

RESULTS

TUNEL-positive keratinocytes were observed in the epidermis underlying the cornoid lamella in all cases examined. Furthermore, loricrin expression was interrupted there, in contrast to involucrin, which was expressed diffusely in the lesional epidermis.

CONCLUSIONS

These results suggest that an abnormal early keratinocyte apoptosis accompanied by dysregulation of terminal differentiation of those cells may be involved in the pathogenesis of porokeratosis.

Disseminated porokeratosis with fatal metastatic squamous cell carcinoma: an additional case of "malignant disseminated porokeratosis"

We report on a patient with a disseminated form of porokeratosis in whom bowenoid lesions and squamous cell carcinoma developed in an apparent sequential progression. Local and disseminated metastases ensued, resulting in the death of the patient. Furthermore, we found an overexpression of the p53 protein in the keratinocytes beneath and adjacent to the cornoid lamella in the porokeratotic lesion and throughout the epidermis in a bowenoid lesion. Although malignancy has been reported previously in various types of porokeratosis, the development of fatal metastatic squamous cell carcinoma in the setting of this disease is a rare event. The histopathologic findings of this case document the association of porokeratotic lesions with bowenoid dysplasia and aggressive squamous cell carcinoma and confirm that a p53 functional aberration can be important in a malignant outcome such as this.

Nitric oxide and endothelin-1,2 in actinic keratosis and basal cell carcinoma: changes in nitric oxide/endothelin ratio

BACKGROUND

Nitric oxide (NO) is an inorganic free radical gas which has cytostatic/cytotoxic actions in tumoral tissues, including gynecologic, breast, and colon cancer. Nitric oxide is also a multifunctional signaling molecule active in many cells of the body, including endothelial cells, macrophages, monocytes, hepatocytes, mast cells, osteoblasts, and astrocytes. Endothelin-1 (ET-1) is a 21-amino acid peptide that stimulates the proliferation of vascular smooth muscle cells, fibroblasts, and keratinocytes, and plays a role in the expression of proto-oncogenes (c-myc, c-fos), which precedes cell proliferation. Similar to NO, ET is secreted by different cell types, including macrophages, monocytes, hepatocytes, endothelial cells, vascular smooth muscle cells, and various tumor cells. Elevated ET-1 levels are observed in pulmonary, hepatocellular, and prostate cancers. Actinic keratosis (AK) and basal cell carcinoma (BCC) are common skin tumors with accentuated hyperkeratinization, hyperpigmentation, and keratinocyte proliferation.

AIM

To investigate plasma NOx (nitrite/nitrate -- the end products of NO metabolism), ET, and the NOx/ET ratio in patients with AK and BCC in comparison with healthy controls.

METHODS

NOx, ET, and the NOx/ET ratio were measured in 13 patients with AK, 12 patients with BCC, and in 16 healthy controls.

RESULTS

Data analysis indicated a significant increase in plasma NOx, ET, and NOx/ET values in BCC patients in comparison with controls (P < 0.001, P < 0.05 and P < 0.001, respectively). Plasma ET levels in AK were also increased in comparison with controls (P < 0.001). When the two study groups (AK and BCC) were compared, a significant increase (P < 0.001) in the NOx/ET ratio in BCC was found.

CONCLUSIONS

The increased plasma ET and NOx levels in AK and, especially, BCC are probably the result of and/or reason for the accentuated hyperkeratinization, hyperpigmentation, and keratinocyte proliferation. The increased production of ET and NO by keratinocytes may function as growth and cytotoxic factors and potential mitogens, and may accelerate further proliferation of these skin tumors. In addition, the increased NOx/ET ratio probably reflects a disturbed equilibrium between these two substances, leading to cell damage and tumor promotion and proliferation.

Guess what! Porokeratosis of Mibelli

A 72-year-old man had noticed, in his early forties, the appearance of well-defined papulous hyperkeratotic lesions, with increasing growth, located on both sides of his feet. After twenty-five years he consulted a dermatologist for the first time. Physical examination showed annular papules and rose-coloured plaques with atrophic centres, some of them hypopigmented, with higher and irregular borders, separated from the surrounding skin by longitudinal and well-defined furrows. The lesions presented variable sizes and shapes, some of them punctate, involving exclusively and in a bilateral form, both sides, back and sole of the feet (Figs. 1 and 2). The patient did not report any subjective symptoms. He was immunocompetent and did not remember that any relative had the same disease, nor had he been subjected to radiation treatment.

p53, mdm-2, and p21 waf-1 in the porokeratoses

The etiology of the porokeratoses is unknown. Overexpression of the p53 tumor suppressor protein and disregulated cell cycle control have been pathogenically implicated. The p53 tumor suppressor gene product is regulated by mdm2 and both gene products influence cell cycle progression through the cyclin-dependent kinase inhibitor p21. Thirty-three cases of the various types of porokeratosis were immunohistochemically studied for p53, mdm2, and p21 proteins. Each of the cases showed increased p53 and decreased mdm2 and p21 expression within keratinocytes underlying cornoid lamella. This study confirms the previous findings of increased p53 staining and expands the potential roles of mdm2 and p21 in the pathogenesis of the porokeratoses.

Overexpression of p2lWaf1/Cip1 immunohistochemical staining in Bowen's disease, but not in disseminated superficial porokeratosis

Disseminated superficial porokeratosis (DSP) consists of multiple small lesions of porokeratosis. Although the pathogenesis of DSP remains unclear, localized cloning of abnormal epidermis has been hypothesized. Malignant cutaneous neoplasms, especially Bowen's disease, have been frequently reported in DSP. Immunopositive p53 has been demonstrated in a variety of human malignant tumours, and its role in oncogenesis and tumour progression is thought to be important. p21Waf1/Cip1 is thought to mediate the signal of p53 induced by DNA damaging agents to arrest the cell cycle. To clarify the role of p53 and p21Waf1/Cip1 in Bowen's disease and DSP, we analysed 12 cases of Bowen's disease and eight cases of DSP by immunohistochemistry. In five of the 12 Bowen's disease patients and two of the eight DSP patients, positive p53 staining was detected. In contrast, whereas p21Waf1/Cip1 overexpression was detected in all Bowen's disease patients, it was not seen in DSP. The present data suggest that p53 immunostaining provides relevant information concerning the pathogenesis of Bowen's disease and DSP. Furthermore, high p21Waf1/Cip1 expression appears to be a useful indicator of tumour activity in Bowen's disease.

Vulvar porokeratosis: case report and review of the literature

We report the first case of vulvar porokeratosis that occurred in a 39-year-old woman with a 30-year history of vulvar pruritus and disfiguring vulvar lesions. Ultrasonic surgical aspiration resulted in resolution of her pruritus and excellent cosmesis. Light microscopy revealed characteristic cornoid lamellae and electron microscopy confirmed the diagnosis of vulvar porokeratosis.

Disseminated superficial porokeratosis with dermal amyloid deposits: case report and immunohistochemical study of amyloid

The association of porokeratosis with dermal amyloid deposits is extremely rare, only three cases are reported in the literature. We describe a case of disseminated superficial porokeratosis (DSP) with clear histologic evidence of amyloid deposition in the upper dermis. The amyloid was typed with an original immunohistochemical assay based on three anticytokeratin antibodies (MNF 116, CK1, KER B). The epidermal origin of the substance (K amyloid) was demonstrated by its strong positivity for MNF 116 and KER B.

Immunohistochemical detection of p53 tumor suppressor protein in porokeratosis

We examined 9 Japanese cases of porokeratosis (4 of the plaque type, 2 of disseminated superficial actinic porokeratosis, 2 of disseminated superficial porokeratosis, and one of giant porokeratosis) for the expression of p53 tumor suppressor protein immunohistochemically, using two anti-p53 antibodies, CM1 and DO1. The same results were obtained with both antibodies. The epidermis central to the cornoid lamellae was positive in 8 of 9 specimens. On the other hand, the peripheral epidermis was positive in 2 of the 9 cases. The epidermis beneath the cornoid lamellae was positive in 3 of the 9 cases. The frequency of p53 positivity was significantly higher in the epidermis central to cornoid lamellae over that beneath or peripheral to them (Fisher's exact probability test, p < 0.05). The majority of squamous cell carcinoma cells arising on giant porokeratosis stained with CM1 and DO1. These data may suggest that the abnormal p53 expression has some relevance to the skin carcinogenesis of porokeratosis.

Overexpression of p53 tumor suppressor protein in porokeratosis

BACKGROUND

p53 is a tumor suppressor nucleoprotein. Mutations of the p53 gene have been found in a variety of malignant neoplasms. Wild-type p53 has a short half-life, possibly only 20 to 30 minutes, and is not present in the nucleus at levels that are detectable with routine immunohistochemical techniques. Mutant p53 has a longer half-life, and is readily detectable with immunoperoxidase staining.

RESULTS

We studied 17 specimens from patients with either porokeratosis of Mibelli or actinic porokeratosis, using immunoperoxidase staining with an antibody directed against the p53. There was staining of lesional keratinocyte nuclei in 16 of 17 specimens, limited in most cases to the zone between cornoid lamellae. Staining for proliferating cell nuclear antigen was increased above background levels in only six of 13 specimens.

CONCLUSIONS

The finding of p53 immunoperoxidase staining in porokeratosis suggests genetic mutation, as occurs in other cutaneous keratinocytic neoplasms, and the lack of corresponding proliferating cell nuclear antigen expression in many specimens indicates that p53 overexpression is not simply a reflection of increased cellular proliferation.