Biological behavior of keratoacanthoma and squamous cell carcinoma: telomerase activity and COX-2 as potential markers

Grading differentiation in cutaneous squamous cell carcinoma: a review of the literature

Poor differentiation is strongly associated with poor outcomes in cutaneous squamous cell carcinoma (CSCC). In addition, the National Comprehensive Cancer Network (NCCN) guidelines designate poorly differentiated tumors as "very high risk". Despite its clear prognostic implications, there is no standardized grading system for CSCC differentiation in common use today. CSCC differentiation is graded inconsistently by both dermatopathologists and Mohs surgeons, and reliability studies have demonstrated suboptimal inter- and intra-rater reliability in both of these groups. The absence of a standardized and reliable grading system has impeded the use of differentiation in CSCC staging, despite its apparent correlation with disease outcomes. We performed a comprehensive review of the literature summarizing historical CSCC differentiation grading systems, as well as grading systems in non-cutaneous head and neck SCC as a point of reference. Relevant articles were identified by searching Embase and PubMed, as well as by reviewing reference lists for additional articles and histology textbook excerpts. CSCC grading systems that were identified and summarized include the historical Broders system, the World Health Organization system, the College of American Pathologists' system, and a system described by a 2023 Delphi consensus panel of dermatopathologists.

Identifying SCC Lesions Capable of Spontaneous Regression by Using Immunohistochemistry: A Systematic Review and Meta-Analysis

INTRODUCTION

Keratoacanthoma (KA) and squamous cell carcinoma (SCC) are two cutaneous conditions with morphological resemblance, which can complicate the diagnosis in some cases. Using immunohistochemistry staining of biomarkers could be beneficial in resolving this obstacle.

OBJECTIVES

We investigated a variety of biomarkers assessed in different studies in order to find the most important and helpful biomarkers for differentiation between SCC and lesions capable of spontaneous regression.

METHODS

MEDLINE via PubMed and Google Scholar database were used to identify relevant literature up to 15 June 2022. The aim of our analyses was to determine the capability of biomarkers to distinguish between SCC and lesions capable of spontaneous regression using calculated individual and pooled odds ratios (OR) and 95% confidence intervals (CI) and I2 tests.

RESULTS

Six potential biomarkers were CD10 with pooled OR= 0.006 (95% CI: 0.001-0.057) and I2=0%; COX-2 with pooled OR=0.089 (95% CI: 0.029-0.269) and I2=17.1%; elastic fibers with pooled OR= 6.69 (95% CI: 2.928-15.281) and I2=0%; IMP-3 with pooled OR=0.145 (95% CI: 0.021-1.001) and I2=44.5%; P53 with pooled OR=0.371 (95% CI: 0.188-0.733) and I2=55.9%; AT1R with OR=0.026 (95% CI: 0.006-0.107).

CONCLUSIONS

We suggest the utilization of the following IHC biomarkers for discrimination between lesions with spontaneous regression such as KA and SCC: CD10, COX-2, and elastic fibers.

Histological Variants of Squamous and Basal Cell Carcinoma in Squamates and Chelonians: A Comprehensive Classification

In the present study, the histological characteristics of squamous cell carcinomas (SCCs) and basal cell carcinomas (BCCs) obtained from 22 squamate and 13 chelonian species were retrospectively evaluated. While the examined tissues were originally diagnosed as 28 SCCs and 7 BCCs based on histological evaluation by a specialty diagnostic service, eight SCCs could be re-classified as BCCs and three SCCs proved to be non-neoplastic lesions. In addition, all SCCs and BCCs were classified into distinct histological variants. The SCCs could be categorized as one SCC in situ, three moderately differentiated SCCs, seven well-differentiated SCCs, and six keratoacanthomas. BCCs were classified as five solid BCCs, four infiltrating BCCs, five keratotic BCCs, and one basosquamous cell carcinoma. In addition, the present study reports the occurrence of BCCs in seven reptile species for the first time. In contrast to what has been documented in humans, IHC staining with the commercially available epithelial membrane antigen and epithelial antigen clone Ber-EP4 does not allow differentiation of SCCs from BCCs in reptiles, while cyclooxygenase-2 and E-cadherin staining seem to have discriminating potential. Although the gross pathological features of the examined SCCs and BCCs were highly similar, each tumor could be unequivocally assigned to a distinct histological variant according to the observed histological characteristics. Based on the results of this study, a histopathological classification for SCCs and BCCs is proposed, allowing accurate identification and differentiation of SCCs and BCCs and their histological variants in the examined reptile species. Presumably, BCCs are severely underdiagnosed in squamates and chelonians.

Gross, Histologic and Immunohistochemical Characteristics of Keratoacanthomas in Lizards

The present study describes the clinical behavior as well as the histopathologic and immunohistochemical characteristics of keratoacanthomas (Kas) in three different saurian species. While Kas presented as two dermal lesions in a bearded dragon (Pogona vitticeps), multicentric Kas were observed in three panther chameleons (Furcifer pardalis) and a veiled chameleon (Chamaeleo calyptratus). Macroscopically, Kas presented as dome-shaped skin tumors with a centralized keratinous pearl and a diameter ranging from 0.1-1.5 cm. In all lizards, Kas were predominantly located at the dorsolateral body wall, and KA of the eyelid was additionally observed in three out of four chameleons. Histologically, KAs presented as relatively well-defined, circumscribed epidermal proliferations that consisted of a crateriform lesion containing a central keratinous pearl with minimally infiltrating borders. In all KAs, a consistent immunohistochemical pattern was observed, with the expression of cyclooxygenase-2, E-cadherin, and pan-cytokeratin. A follow-up period of one to two years was established in all lizards. While no recurrence was observed in the panther chameleons, recurrence of a single keratoacanthoma was observed in the bearded dragon after one year, and in the veiled chameleon, multicentric keratoacanthomas reappeared during a follow-up period of two years. We describe KA as a previously unrecognized neoplastic entity in lizards that constitutes a low-grade, non-invasive but rapidly growing skin tumor that may show a multicentric appearance, especially in chameleons. As previously postulated for dermal squamous cell carcinomas (SCC), artificial ultraviolet lighting may play an important role in the oncogenesis of KAs in lizards. Although dermal SCCs in lizards show similar predilection sites and gross pathologic features, our results suggest that KA should be considered as a histologic variant of SCC that represents a rather benign squamous proliferation in comparison to conventional SCCs. Early diagnosis of KA and reliable discrimination from SCCs are essential for the prognosis of this neoplastic entity in lizards.

Differences in the mitochondrial microsatellite instability of Keratoacanthoma and cutaneous squamous cell carcinoma

Keratoacanthoma (KA) is a common cutaneous neoplasm which often resembles typical squamous cell carcinoma (SCC) in both its clinical and historical presentation. Several studies have attempted to identify methods for distinguishing between KA and SCC, however, none of these have proven to play any obvious roles in these tumors. Given this we went on to evaluate mitochondrial microsatellite instability (mtMSI) in KA and SCC in an effort to understand these tumors better. DNA was isolated from paired normal and tumoral tissues donated by 57 KA patients and 43 SCC patients. MtMSI was then analyzed using eight microsatellite markers and was observed in 2 (3.5%) of the 57 KA patients and 8 (18.6%) of the 43 SCC patients, respectively. MtMSI was also shown to affect different locations depending on tumor type. In KA patients, mtMSI was detected at mitochondrial D514 D-loop and presented with (CA) n repeats, in contrast, all of the SCC patient experienced mtMSI at the D310 with (C)n repeats of the D-loop region. These differences in location were found to be significant, which may support the hypothesis that KA and SCC have different pathogenetic pathways. Our results also suggest that mtMSI may be a candidate for developing novel differential diagnostic methods for KA and SCC.

Clinical, histopathological and immunohistochemical study of keratoacanthoma

Keratoacanthoma (KA) is an epithelial tumor of the skin, classically considered as having a malignant transformation risk of 15%; however, many authors and the new World Health Organization (WHO) Classification of skin tumors consider KA as an incipient variant of the cutaneous squamous cell carcinoma (SCC). The aims of the study were to assess the clinical, histopathological (HP) and immunohistochemical (IHC) aspects of the KA and the role of these factors in malignancy occurrence. The studied group comprises 194 patients diagnosed with KA or malignant KA, hospitalized in the Clinic of Dermatology, Emergency County Hospital, Craiova, Romania, between 2006 and 2019. There were 83 males and 111 females, aged 34 to 90 years, 57.21% of the patients being from the rural environment. The histopathology diagnosed 51 KAs and 143 malignant KAs (SCCs). Clinical diagnosis had a limited value in detecting the absence or presence of malignancy in the KA lesion, due to a low accuracy (36.08% and 29.89%, respectively) and specificity (23.07% and 27.02%, respectively); therefore, the HP exam of the surgical excision specimen has a paramount importance in establishing the diagnosis. IHC analysis revealed that the immunostainings for apoptosis-associated proteins and keratinocyte proliferative activity [p53, B-cell lymphoma-2 (Bcl-2), Ki-67 and proliferating cell nuclear antigen (PCNA)] provide some arguments to differentiate between KA and SCC in the studied cases. The correlation of clinical, HP and IHC data lead to an accurate diagnosis of KA; moreover, the clinical, HP and IHC data sustain the idea that KA is a particular form of well-differentiated SCC, which require an active therapeutic attitude.

Expression of Cyclooxygenase-2 in Human Epithelial Skin Lesions: A Systematic Review of Immunohistochemical Studies

Permanent, elevated expression of cyclooxygenase-2 (COX-2) in keratinocytes of epidermis can stimulate its hyperplasia and constitute a factor promoting cancer development, as demonstrated in animal models. Intratumoral level and localization of COX-2 in epithelial lesions of human skin was examined immunohistochemically in 26 studies. In squamous cell carcinomas (SCCs), strong staining was observed with great compatibility. High COX-2 detectability throughout the entire tumor mass could be helpful in the finding of SCC cells. However, in basal cell carcinomas, and precancerous lesions, frequency and detection level of this protein, as well as the type and/or localization of stained cells within the tumor, varied among different research groups. The discrepancies may be due to the heterogeneity of each of these 2 groups of lesions. However, differences in COX-2 staining in normal skin indicate also possible methodological reasons. In general, COX-2 levels were significantly decreased in basal cell carcinomas compared with SCCs, which could be used in the differential diagnosis of these cancers. Reduced, although heterogenous, COX-2 expression in precancerous lesions may suggest its association with SCC development. These observations are consistent with data on the efficacy of preventive and therapeutic effects of nonsteroidal anti-inflammatory drugs that are COX-2 inhibitors.

The role of p53, Ki-67 and laminin expression in the differential diagnosis of keratoacanthoma and well-differentiated SCC

Introduction

We have aimed to evaluate the difference between the expression of p53, Ki-67, and laminin in keratoacanthoma and well-differentiated SCC (SCC) and to determine its importance in differential diagnosis.

Methods

This study totally included 46 cases consisting of 23 cases with keratoacanthoma and 23 with SCC. As well as age, gender, localization, and diameter of the lesion, the expression of p53, Ki-67 and laminin was evaluated.

Results

No statistically significant difference was found between KA and well-differentiated SCC in terms of diameter, age, and localization. There was a statistically significant difference between KA and well-differentiated SCC in terms of p53 and Ki-67 staining (P < 0.001). Increased expression of p53 and Ki-67 was found in well-differentiated SCC. A statistically significant correlation was present between the expression of p53 and Ki-67 in KA. A statistically significant difference was detected between KA and well-differentiated SCC in terms of laminin staining (P = 0.018). Increased laminin expression was determined in well-differentiated SCC.

Conclusion

We have determined in this study that p53, Ki-67 and laminin may be used as adjuvant immunohistochemical markers in differential diagnosis of KA and well-differentiated SCC.

Expression of prostaglandin E2 receptor subtypes in human pterygium and normal conjunctiva: immunohistochemical study

PURPOSE

In the present study, we aimed to evaluate the expression of EP receptors in primary and recurrent human pterygium tissues.

METHODS

Pterygium samples were collected from 65 patients with primary pterygium and 16 patients with recurrent pterygium. Normal conjunctival tissues were collected from nasal interpalpebral area from 17 patients without systemic and any other ocular pathology. Expression of EP receptors was evaluated by immunohistochemistry. The median value for each receptor staining score (RSS) was determined in normal conjunctival specimens. In this study, RSS of > median value was defined as positive staining or high expression and ≤ median value as negative staining or weak expression in specimens. Chi-square test was used for statistical analysis, and p value of less than 0.05 was considered significant.

RESULTS

Stromal expression of EP1 was significantly higher in primary and recurrent pterygium specimens compared to normal conjunctival tissues (p = 0.007 and p = 0.002, respectively). Epithelial expressions of EP2 and EP3 were significantly lower in primary pterygium specimens compared to normal conjunctival tissues (p = 0.005 and p < 0.0001, respectively), and stromal expressions were insignificant. Stromal expression of EP4 was significantly higher in primary and recurrent pterygium specimens compared to normal conjunctival tissues (p = 0.002 and p = 0.012, respectively).

CONCLUSIONS

Expression of EP receptors has been up- or downregulated in primary and recurrent pterygium tissues, and these receptors may play a role in formation and recurrence of pterygium.

Keratoacanthoma of the lip: A case report with emphasis on histogenesis

Keratoacanthoma (KA) is a benign epithelial tumor which presents clinically as a proliferating dome-shaped keratin-filled crater. The lesion occurs predominantly upon sun-exposed areas of the body and is known to arise from hair follicle. Actinic rays are a major contributing factor in the etiology. It simulates grossly as well as microscopically a low-grade squamous cell carcinoma. KAs occur habitually on the mucous membrane as well, but their origin in these cases is debatable, owing to the lack of hair follicles in these sites. Our report is an attempt to demonstrate the cells that could be responsible for initiation of this lesion on the oral mucosa.

The Role of p16, p21, p27, p53 and Ki-67 Expression in the Differential Diagnosis of Cutaneous Squamous Cell Carcinomas and Keratoacanthomas: An Immunohistochemical Study

BACKGROUND

Distinguishing squamous cell carcinoma (SCC) from keratoacanthoma (KA) by histopathological features may not be sufficient for a differential diagnosis, as KAs may, in some cases, imitate well-differentiated SCCs.

AIMS

In this study, we investigated whether the expression of the p16, p21, p27, p53 genes and a Ki-67 proliferation index are useful in distinguishing between these two tumors.

STUDY DESIGN

Cross-sectional study.

METHODS

Immunohistochemistry was used to investigate the expression of the p16, p21, p27, p53 genes and the Ki-67 proliferation index was investigated in well-differentiated SCC with KA-like features (n=40) and KA (n=30).

RESULTS

The results of all of the examined markers, except for p27 (p16, p21, p53, and Ki-67) were found to be significantly different between the SCC and KA samples (p<0.05).

CONCLUSION

In well-differentiated SCC with KA-like features and KA cases where the differential diagnosis is difficult from a histopathological perspective, the use of p16, p21, p53 expression and a Ki-67 proliferation index can be useful for the differential diagnosis of SCCs and KAs.

Keratoacanthoma (KA): An update and review

Keratoacanthoma (KA) is a common but underreported tumor of the skin. Two striking features of KA are its clinical behavior with spontaneous regression after rapid growth and its nosological position on the border between benignity and malignancy. We review current knowledge on the clinical, histopathological, and dermoscopic features of KA to ensure a proper diagnosis and describe its variants, including different types of multiple KAs. We highlight current concepts of KA ethiopathogenesis with special emphasis on the genetic background of multiple familial KA, the role of Wnt signaling pathway, and induction of KA by BRAF inhibitors and procedures of esthetic dermatology. Finally, treatment strategies are presented with surgical excision as a first option, followed by other modalities, including intralesional chemotherapy, topical and systemic agents, lasers, cryotherapy, and photodynamic therapy.

Cutaneous keratoacanthomas/squamous cell carcinomas associated with neutralization of transforming growth factor β by the monoclonal antibody fresolimumab (GC1008)

Fresolimumab is an antibody capable of neutralizing all human isoforms of transforming growth factor beta (TGFβ) and has demonstrated anticancer activity in investigational studies. Inhibition of TGFβ by fresolimumab can potentially result in the development of cutaneous lesions. The aim of this study was to investigate the clinical, histological, and immunohistochemical characteristics of cutaneous neoplasms associated with fresolimumab. Skin biopsies (n = 24) were collected and analyzed from patients (n = 5) with treatment-emergent, cutaneous lesions arising during a phase 1 study of multiple doses of fresolimumab in patients (n = 29) with melanoma or renal cell carcinoma. Blinded, independent histological review and measurements of Ki-67, p53, and HPV integration were performed. Based on central review, four patients developed lesions with histological characteristics of keratoacanthomas, and of these patients, a single case of well-differentiated squamous cell carcinoma was also found. Expression of Ki-67, no evidence of p53 overexpression, and only focal positivity for human papillomavirus RNA by in situ hybridization in 4/18 cases were consistent with these findings. Following completion of fresolimumab, lesions spontaneously resolved. Therefore, benign, reversible keratoacanthomas were the most common cutaneous neoplasms observed, a finding of importance for adverse event monitoring, patient care, and optimization of therapies targeting TGFβ.

Possible Spontaneous Regression of a Metastatic Lesion of Keratoacanthoma-Like Squamous Cell Carcinoma in a Regional Lymph Node

We report herein a case of keratoacanthoma-like squamous cell carcinoma in an 82-year-old male that showed regional lymph node metastasis followed by self-regression of the metastatic lesion. This case is consistent with the previously reported observation that tumors compatible with the clinical features of keratoacanthoma may have malignant biological potential, however, it also demonstrates that even metastatic lesions may exhibit self-regression similar to that observed for primary lesions. Despite the view that keratoacanthoma-like squamous cell carcinoma may represent a variant of squamous cell carcinoma, occasionally it undergoes a unique clinical course.

Phase I study of GC1008 (fresolimumab): a human anti-transforming growth factor-beta (TGFβ) monoclonal antibody in patients with advanced malignant melanoma or renal cell carcinoma

Background

In advanced cancers, transforming growth factor-beta (TGFβ) promotes tumor growth and metastases and suppresses host antitumor immunity. GC1008 is a human anti-TGFβ monoclonal antibody that neutralizes all isoforms of TGFβ. Here, the safety and activity of GC1008 was evaluated in patients with advanced malignant melanoma and renal cell carcinoma.

Methods

In this multi-center phase I trial, cohorts of patients with previously treated malignant melanoma or renal cell carcinoma received intravenous GC1008 at 0.1, 0.3, 1, 3, 10, or 15 mg/kg on days 0, 28, 42, and 56. Patients achieving at least stable disease were eligible to receive Extended Treatment consisting of 4 doses of GC1008 every 2 weeks for up to 2 additional courses. Pharmacokinetic and exploratory biomarker assessments were performed.

Results

Twenty-nine patients, 28 with malignant melanoma and 1 with renal cell carcinoma, were enrolled and treated, 22 in the dose-escalation part and 7 in a safety cohort expansion. No dose-limiting toxicity was observed, and the maximum dose, 15 mg/kg, was determined to be safe. The development of reversible cutaneous keratoacanthomas/squamous-cell carcinomas (4 patients) and hyperkeratosis was the major adverse event observed. One malignant melanoma patient achieved a partial response, and six had stable disease with a median progression-free survival of 24 weeks for these 7 patients (range, 16.4–44.4 weeks).

Conclusions

GC1008 had no dose-limiting toxicity up to 15 mg/kg. In patients with advanced malignant melanoma and renal cell carcinoma, multiple doses of GC1008 demonstrated acceptable safety and preliminary evidence of antitumor activity, warranting further studies of single agent and combination treatments.

Trial Registration

Clinicaltrials.gov NCT00356460

Tretinoin cyclodextrin complex (RA/CyD) causes less irritation with an equal antiwrinkle effect compared with conventional tretinoin: clinical and histologic studies of photoaged skin

BACKGROUND

Topical tretinoin [all-trans-retinoic acid (RA)] currently is widely used to treat photoaged skin. However, undesirable side effects such as erythema, irritation, and scaling are unavoidable and limit the use of tretinoin. To address these issues, the authors developed the tretinoin cyclodextrin complex (RA/CyD), which is tretinoin encapsulated by cyclodextrin. Cyclodextrins are cyclic oligosaccharides commonly used in food additives and fabric fresheners. This study aimed to evaluate the antiwrinkle effect of RA/CyD and alleviation of the side effects compared with RA treatment alone.

METHODS

In this study, 12 photoaged patients completed an 8 week study using RA and RA/CyD in a double-blind manner. Before and after the treatment, the patients' evaluations, wrinkle scores, skin elasticity, and wrinkle area measurement using skin replica were evaluated. Three men were recruited for histologic analysis.

RESULTS

The patients reported that undesirable irritant reactions were more moderate with RA/CyD than with RA. In the assessment of wrinkle scores, skin elasticity, and wrinkle area measurement, RA/CyD demonstrated an antiwrinkle effect statistically equal to that of RA. In histology, both RA/CyD and RA demonstrated epidermal hyperplasia. In immunohistochemistry, inflammation induced by RA/CyD was more moderate than that induced by RA.

CONCLUSION

The findings show that RA and RA/CyD result in the equivalent clinical improvement for patients with photoaging. The use of RA/CyD overcomes the drawbacks of RA while possessing equal effect. It is expected that CyD will broaden tretinoin treatment.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors at www.springer.com/00266.

[The value of laminin-322 staining in distinguishing between keratoacanthoma, keratoacanthoma with areas of squamous cell carcinoma, and crateriform squamous cell carcinoma]

INTRODUCTION

Keratoacanthoma is a fast-growing crateriform skin tumor. Approximately 25% of such tumors undergo malignant transformation and develop areas of squamous cell carcinoma (SCC). The presence of laminin-322 has been associated with progression to invasive forms of SCC. The aim of this study was to determine whether or not immunohistochemical staining for laminin-322 would be of value in distinguishing between keratoacanthomas, keratoacanthomas with areas of squamous cell carcinoma, and SCCs.

MATERIAL AND METHODS

Seventy-four lesions were selected from the pathology archives of our hospital and divided into 4 groups: 20 keratoacanthomas without SCC, 20 keratoacanthomas with areas of squamous cell carcinoma, 20 invasive SCCs (8 with crateriform morphology) unrelated to keratoacanthoma, and 14 problem lesions (keratoacanthomas with areas suggestive of SCC). All 74 lesions were stained for laminin-322.

RESULTS

Laminin-322 staining was strongly positive both in areas of SCC in keratoacanthomas with malignant transformation and in invasive SCCs (mostly at the invasive front of the SCC). However, in benign keratoacanthomas, it was only weakly positive and furthermore it was confined to isolated cells or small groups of cells. The 14 problem lesions were reexamined after laminin-322 staining and 8 were diagnosed as keratoacanthomas with incipient SCC and 6 as keratoacanthomas without SCC.

CONCLUSIONS

Laminin-322 staining is different in keratoacanthomas and SCCs and would thus be a useful test for differentiating keratoacanthomas from both invasive SCCs and keratoacanthomas with areas of squamous cell carcinoma. It would also be of value in diagnosing keratoacanthomas with areas suggestive of SCC or with incipient SCC.

Sorafenib-induced premalignant and malignant skin lesions

PURPOSE

To review characteristics of patients who develop premalignant and malignant skin lesions while on sorafenib therapy and discuss implications for subsequent treatment of their primary malignancies.

BACKGROUND

Sorafenib is a newly developed multitargeted protein kinase inhibitor reported to induce a variety of adverse cutaneous effects, rarely including actinic keratoses, keratocanthomas, and squamous cell carcinomas (SCCs).

METHODS

Published reports of individuals who have developed cutaneous lesions demonstrating atypia of the epidermis are reviewed. In addition, a 77-year-old man who developed not only an SCC but also verrucas within one month of taking sorafenib monotherapy for metastatic adenocarcinoma of the lung is described.

RESULTS

Cutaneous lesions develop most commonly in Caucasian men older than 40 years without previous histories of skin cancer, within two weeks to three years of starting sorafenib therapy. Currently there is no definitive explanation for the relationship between sorafenib and cutaneous neoplasms. Management typically involves treatment of skin lesions with cryotherapy or excision with at least a brief discontinuation of sorafenib. In patients whose primary malignancies were responding well, sorafenib therapy was continued with close follow-up.

CONCLUSIONS

The possibility of rapidly developing actinic keratoses, keratocanthomas, verrucas, and SCC during treatment with sorafenib, warrants close dermatologic follow-up and a lower threshold for biopsy and treatment of suspicious cutaneous lesions. Development of a sorafenib-induced SCC is not an absolute contraindication for continued use of sorafenib therapy; however, the drug should be briefly discontinued until lesions are treated.

Differential expression of ezrin in epithelial skin tumors: cytoplasmic ezrin immunoreactivity in squamous cell carcinoma

BACKGROUND

Ezrin is a cytoskeleton linker protein that is actively involved in regulating the growth and metastatic capacity of cancer cells. The purpose of the study was to assess the expression pattern of ezrin in normal skin and various epithelial neoplasms.

METHODS

We used immunohistochemical techniques to examine the expression of ezrin in paraffin-embedded tissues of squamous cell carcinoma (n = 23), basal cell carcinoma (n = 10), Bowen's disease (n = 10), actinic keratosis (n = 10), keratoacanthoma (n = 9), seborrheic keratosis (n = 5), psoriasis vulgaris (n = 5), and normal control skin (n = 5).

RESULTS

In Bowen's disease, actinic keratosis, keratoacanthoma, and seborrheic keratosis, ezrin was dominantly expressed in the cell membrane except for the cornified layer. In squamous cell carcinoma (SCC) specimens, the percentage of ezrin-positive cells was increased compared with Bowen's disease, actinic keratosis, keratoacanthoma, and seborrheic keratosis. Especially in SCC samples, ezrin expression was markedly expressed in the cytoplasm. In addition, there was a correlation between the pattern of ezrin expression and tumor differentiation in SCC. Basal cell carcinoma showed intense and diffuse staining especially in the solid growth pattern.

CONCLUSIONS

Our findings suggest that dysregulation of ezrin may be important in the development of cutaneous epithelial malignancies and tumor grade. We suggest that the cytoplasmic localization of ezrin may be useful in the diagnosis of skin SCC.

Keratoacanthoma: hyperplasia, benign neoplasm, or a type of squamous cell carcinoma?

Keratoacanthomas are common self limited squamous proliferations. They have been considered a benign neoplasm with involution and complete resolution within few months. Although considered the prototypical example of cutaneous pseudomalignancy, some believe that these tumors are squamous cell carcinomas and through the years there have been sporadic reports of "metastasizing keratoacanthomas". The question has been raised as to whether keratoacanthoma is an unreliable histological diagnosis or these tumors have a latent, albeit rare, malignant potential. To date, just a handful of "metastasizing keratoacanthomas" have been reported. Since a benign lesion is incapable of metastasis, some other explanation must be considered; the most likely one being a misdiagnosis. While it is clear that in some cases, the histological and cytological features of squamous cell carcinoma and keratoacanthoma are difficult to distinguish by current techniques, these occasional limitations in diagnosis do not make keratoacanthomas a carcinoma. We believe the evidence supports that keratoacanthomas are benign squamous proliferations. The diagnosis can be made with confidence in appropriate biopsies and using well established clinicopathological criteria.

Cyclooxygenase-2 expression in primary and recurrent pterygium

PURPOSE

Pterygium is a proliferative, inflammatory, and invasive ocular surface disease associated with excessive ultraviolet radiation exposure and has several tumor-like characteristics. Cyclooxygenase-2 (COX-2) is an inducible enzyme and recently increased expression of the enzyme was found in many cancers and premalign lesions. This study was conducted to identify the COX-2 expression in pterygium tissues.

METHODS

Immunohistochemical staining using a primary antibody for COX-2 was performed on 30 specimens with primary pterygium (20 pterygium without recurrence and 10 pterygium which recurred during a 12-month follow-up), 11 specimens with recurrent pterygium, and 8 specimens of conjunctival tumor. As a control we used 10 specimens of normal conjunctiva. Extent and intensity of cytoplasmic and membranous staining in epithelial cells were evaluated.

RESULTS

Higher expression of COX-2 was detected in conjunctival tumor (87.5%) specimens and recurrent pterygium specimens (72.7%) compared to the both normal conjunctiva (30%) and primary pterygium without recurrence (30%). COX-2 expression in primary pterygium tissues with recurrence (60%) was not different from primary pterygium without recurrence (p=0.114) and recurrent pterygium (p=0.537). However, recurrent pterygium tissues were found to express higher COX-2 than primary pterygium without recurrence (p=0.022).

CONCLUSIONS

COX-2 expression is increased in recurrent pterygium tissues and COX-2 expression may be a marker for the prediction of recurrence.

Are keratoacanthomas variants of squamous cell carcinomas? A comparison of chromosomal aberrations by comparative genomic hybridization

Keratoacanthoma (KA) is a benign keratinocytic neoplasm that usually presents as a solitary nodule on sun-exposed areas, develops within 6-8 weeks and spontaneously regresses after 3-6 months. KAs share features such as infiltration and cytological atypia with squamous cell carcinomas (SCCs). Furthermore, there are reports of KAs that have metastasized, invoking the question of whether or not KA is a variant of SCC. To date no reported criteria are sensitive enough to discriminate reliably between KA and SCC, and consequently there is a clinical need for discriminating markers. We screened fresh frozen material from 132 KAs and 37 SCCs for gross chromosomal aberrations by using comparative genomic hybridization (CGH). Forty-nine KAs (37.1%) and 31 SCCs (83.7%) showed genomic aberrations, indicating a higher degree of chromosomal instability in SCCs. Gains of chromosomal material from 1p, 14q, 16q, 20q, and losses from 4p were seen significantly more frequently in SCCs compared with KAs (P-values 0.0033, 0.0198, 0.0301, 0.0017, and 0.0070), whereas loss from 9p was seen significantly more frequently in KAs (P-value 0.0434). The patterns of recurrent aberrations were also different in the two types of neoplasms, pointing to different genetic mechanisms involved in their developments.

Muir-Torre Syndrome With Intriguing Squamous Lesions

Muir-Torre syndrome (MTS) is an autosomal, dominantly inherited disorder characterized by sebaceous neoplasms and visceral malignancies. We report a 56-year-old woman who underwent resections of extraocular sebaceous carcinoma, sebaceous epithelioma, actinic keratosis, and keratoacanthoma (KA)-like squamous cell carcinoma (SCC) with venous invasion metachronously over a 9-year period. Because of the mixed, unusual features of the skin lesions, and her history of endometrial and colorectal cancers that had been resected 12 years and 1 year, respectively, before the present event, a possible diagnosis of Muir-Torre syndrome was suggested. Immunohistochemical studies revealed loss of hMSH2 expression in all the cutaneous lesions including the actinic keratosis, and also in the endometrial and colorectal cancers. This patient presented with intriguing squamous lesions including keratoacanthoma-like squamous cell carcinoma that showed venous invasion and actinic keratosis, and associated loss of hMSH2 expression, in addition to the sebaceous neoplasms typical of Muir-Torre syndrome.

p16 Expression in Keratoacanthomas and Squamous Cell Carcinomas of the Skin: An Immunohistochemical Study

Context.—Distinguishing between keratoacanthoma (KA) and squamous cell carcinoma (SCC) is not an uncommon histologic diagnostic dilemma.

Objective.—To determine if p16 expression is useful in the differential diagnosis of SCC and KA.

Design.—We studied the expression of p16 by immunohistochemistry in 24 KAs, 24 infiltrating SCCs of the skin, 4 histologically indeterminate lesions, and 8 nonmalignant keratoses.

Results.—A range of immunohistochemical p16 expression was seen in KAs and SCCs in terms of the thickness of lesional staining and the percentage of cells staining. No significant difference in measures of p16 expression was identified among the KAs, the SCCs, the indeterminate lesions, or the benign keratoses.

Conclusions.—These findings suggest that p16 is not a useful marker to distinguish between KA and SCC, supporting the similarity between the 2 lesions; p16 alterations appear to play a role in the pathogenesis of both KA and SCC.

Possible key role of granzyme B in keratoacanthoma regression

It is still controversial whether keratoacanthoma is to be considered as a well differentiated variant of squamous cell-carcinoma or a separate entity. As opposed to malignant potential of squamous cell-carcinoma, keratoacanthoma is characterized by a spontaneous regression. However, in some cases, otherwise typical keratoacanthoma can behave aggressively showing the signs of perineural and perivascular invasion and metastases in regional lymph nodes. The most important feature that separates these two closely related entities is a tendency of keratoacanthoma to regress. Causes and detailed mechanism of this regression are still not completely elucidated. Within the past few years, it has become evident that the molecular events regulating cell survival and apoptosis are important contributors to the overall kinetics of benign and malignant cell growth. Immunological mechanisms have been implicated in a phenomenon of spontaneous tumor regression. Recent studies suggested that the tumor regression is dependent mainly on the immune response mediated by cytotoxic T lymphocytes (CD8+), together with helper T cells (CD4+). Cytotoxic T lymphocytes can kill tumor cells and mediate tumor regression in vivo through two distinct molecular mechanisms: Fas/Fas ligand and granzyme B/perforin mediated pathways. Tumor cells are capable of developing different escape mechanisms in order to overcome their sensitivity to apoptotic signals. However, granzyme B, contained in cytolytic granules released upon target cell recognition, can also cause tumor cell death and consequently tumor regression by direct damage to non-nuclear structures through a caspase-independent pathway. Therefore, we propose a key role of plasticity in the granzyme B mediated cell death pathway in the killing of changed tumor cells, resulting in keratoacanthoma regression through apoptosis or direct damage of tumor cells. On the other hand, insufficient activation of cytotoxic T lymphocytes and decreased release or activity of granzyme B could be responsible for squamous cell-carcinoma progression and occasional aggressive behavior in keratoacanthomas. As a first step in confirming or refuting our hypothesis, we suggest a thorough immunohistochemical study of the presence of granzyme B and its activity in keratoacanthoma and squamous cell-carcinoma samples. To our knowledge, no such study has been performed so far.