Topical treatment of basal cell carcinoma with tazarotene: a clinicopathological study on a large series of cases

Use of retinoids in dermatology

Background: Retinoid, whose existence was first known in the 20th century, was initially referred to as a naturally occurring substance with vitamin A action. However, now it has become a generic term for all substances exhibiting an active action through the retinoid receptor located in the nucleus of the cells. Retinoids are biologically important substances involved in many functions, including reproduction, embryonic morphogenesis, regulation of epithelial proliferation and differentiation, reduction of sebaceous gland, immune and anti-inflammatory effects, tumor prevention, and effects on extracellular matrix components.Current Concepts: Topical retinoids are used to treat several conditions, including acne, photoaging, and psoriasis. Their side effects are dose-related skin irritations, while teratogenicity risk is rare to non-existent. Systemic retinoids are a treatment of choice for acne and keratinization disorders. They are also useful for the treatment of psoriasis, pityriasis rubra pilaris, cutaneous T-cell lymphoma, and chronic hand eczema. Systemic retinoid therapy requires the careful patient selection and monitoring due to associated teratogenicity. Other important side effects are hypertriglyceridemia, dryness of lips, blepharoconjunctivitis, bone pain, increased muscle tone, myopathy, hypothyroidism, and neutropenia.Discussion and Conclusion: Awareness of the side effects and proper use of retinoids are important for successful treatment outcomes of the above-mentioned dermatological conditions.

Patidegib in Dermatology: A Current Review

Background: Basal cell carcinoma is one of the most common types of non-melanoma skin cancers, which can be locally destructive despite low-rate metastasis. Surgery is the treatment of choice, but it lacks of efficacy on advanced cases. Hedgehog pathway inhibitors are a class of drugs providing a new therapeutic option for patients affected by advanced disease. Besides systemic therapy, such as vismodegib and sonidegib, also topical inhibitors have been developed. Patidegib is able to decrease tumor burden, reducing the adverse effects induced by systemic targeted therapies. Methods: We performed comprehensive research to summarize the use of patidegib in advanced and recurrent aggressive basal cell carcinomas. Only English language human studies were included in the search. Results: Seven trials reported the application of patidegib. Both topical and systemic patidegib demonstrated safety, tolerability, and efficacy in naïve patients with stage II and III basal cell carcinomas, while stage IV disease and not-naïve patients did not show any benefit. Conclusion: Unlike systemic Hedgehog pathway inhibitors, patidegib 2% gel is not associated with systemic adverse effects and allows a better patient management. Considering the multidisciplinary management of neoplasia, in the era of precision medicine, it is mandatory to confide in pharmacogenomics to obtain personalized combined or sequential therapies.

A review of emerging and non-US FDA-approved topical agents for the treatment of basal cell carcinoma

Although surgical therapy continues to be the gold standard for the treatment of basal cell carcinoma given high cure rates and the ability to histologically confirm tumor clearance, there are a number of nonsurgical treatment options that may be considered based on individual tumor characteristics, functional and cosmetic considerations, patient comorbidities and patient preference. Topical 5-fluorouracil 5% cream and imiquimod 5% cream have been US FDA-approved for the treatment of superficial basal cell carcinoma. Additionally, a number of new and emerging topical agents and techniques have been described for the treatment of basal cell carcinoma and will be reviewed herein.

Pathogenesis of Keratinocyte Carcinomas and the Therapeutic Potential of Medicinal Plants and Phytochemicals

Keratinocyte carcinoma (KC) is a form of skin cancer that develops in keratinocytes, which are the predominant cells present in the epidermis layer of the skin. Keratinocyte carcinoma comprises two sub-types, namely basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). This review provides a holistic literature assessment of the origin, diagnosis methods, contributing factors, and current topical treatments of KC. Additionally, it explores the increase in KC cases that occurred globally over the past ten years. One of the principal concepts highlighted in this article is the adverse effects linked to conventional treatment methods of KC and how novel treatment strategies that combine phytochemistry and transdermal drug delivery systems offer an alternative approach for treatment. However, more in vitro and in vivo studies are required to fully assess the efficacy, mechanism of action, and safety profile of these phytochemical based transdermal chemotherapeutics.

Trifarotene: A Current Review and Perspectives in Dermatology

Retinoids have numerous applications in inflammatory, dyskeratotic, and oncohematology diseases. Retinoids have now reached the fourth generation, progressively reducing toxicity whilst increasing their efficacy. Trifarotene is a new fourth-generation retinoid with a selective action on RAR-γ. In this review, we reported the trials—both concluded and in progress—including the use of trifarotene in dermatological diseases. Studies were identified by searching electronic databases (MEDLINE, EMBASE, PubMed, Cochrane, Trials.gov) from 2012 to today and reference lists of respective articles. Only articles published in English language were included. Randomized trials evaluating trifarotene tolerability, safety, and efficacy in congenital ichthyosis and acne have demonstrated great results and mild side effects, leading to the approval by the FDA of trifarotene for the treatment of lamellar ichthyosis in 2014, and of acne vulgaris in October 2019. No high-quality randomized clinical trials have evaluated the treatment of primary cutaneous lymphomas with trifarotene. Finally, we are hypothesizing future perspectives in the treatment of non-melanoma skin cancers, fungal infections, photoaging, and hand-foot skin reactions with trifarotene.

Retinoic Acid and Its Derivatives in Skin

The retinoids are a group of compounds including vitamin A and its active metabolite all-trans-retinoic acid (ATRA). Retinoids regulate a variety of physiological functions in multiple organ systems, are essential for normal immune competence, and are involved in the regulation of cell growth and differentiation. Vitamin A derivatives have held promise in cancer treatment and ATRA is used in differentiation therapy of acute promyelocytic leukemia (APL). ATRA and other retinoids have also been successfully applied in a variety of dermatological conditions such as skin cancer, psoriasis, acne, and ichthyosis. Moreover, modulation of retinoic acid receptors and retinoid X (or rexinoid) receptors function may affect dermal cells. The studies using complex genetic models with various combinations of retinoic acid receptors (RARs) and retinoid X (or rexinoid) receptors (RXRs) indicate that retinoic acid and its derivatives have therapeutic potential for a variety of serious dermatological disorders including some malignant conditions. Here, we provide a synopsis of the main advances in understanding the role of ATRA and its receptors in dermatology.

Beyond Mohs surgery and excisions: A focused review of treatment options for subtypes of basal cell carcinoma

Basal cell carcinoma (BCC) is the most common nonmelanoma skin cancer. It originates from undifferentiated cells in the basal cell layer of the epidermis or from the outer root sheath of the hair follicle. The most important factor in development of BCC is ultraviolet radiation. Surgery is considered the gold standard of treatment for BCC. However, nonsurgical options are available for individuals who are unsuitable for surgery. The purpose of this review is to summarize the efficacy and indications of alternative, nonsurgical treatments that can be used in the management of BCC. An extensive literature review was performed for the nonsurgical options for the treatment of BCC. Resources searched included PubMed and Google Scholars, limited to the years 1995 to 2020. Key words searched included BCC, destructive methods, photodynamic therapy (PDT), radiotherapy, topical medication, laser, hedgehog pathway inhibitors (HPIs). The most relevant results such as systematic reviews, randomized controlled trials, or comparative studies were selected to provide a summary for the most common nonsurgical methods used for treating BCC. Effective nonsurgical treatments for BCC include destructive methods (eg, curettage alone, cryosurgery, or electrodessication), PDT, topical medications, radiotherapy, laser, and HPIs. Nonsurgical therapeutic alternatives are safe and effective for the treatment of BCC. Factors such as tumor location, size, and histopathological subtype should be taken into consideration when selecting optimal treatment. In addition to clinical factors, cosmetic results and patient preference should be considered.

Carotenoids in Cancer Apoptosis-The Road from Bench to Bedside and Back

An incidence and mortality of cancer are rapidly growing worldwide, especially due to heterogeneous character of the disease that is associated with irreversible impairment of cellular homeostasis and function. Targeting apoptosis, one of cancer hallmarks, represents a potent cancer treatment strategy. Carotenoids are phytochemicals represented by carotenes, xanthophylls, and derived compounds such as apocarotenoids that demonstrate a broad spectrum of anti-cancer effects involving pro-apoptotic signaling through extrinsic and intrinsic pathways. As demonstrated in preclinical oncology research, the apoptotic modulation is performed at post-genomic levels. Further, carotenoids demonstrate additive/synergistic action in combination with conventional oncostatic agents. In addition, a sensitization of tumor cells to anti-cancer conventional treatment can be achieved by carotenoids. The disadvantage of anti-cancer application of carotenoids is associated with their low solubility and, therefore, poor bioavailability. However, this deficiency can be improved by using nanotechnological approaches, solid dispersions, microemulsions or biofortification that significantly increase the anti-cancer and pro-apoptotic efficacy of carotenoids. Only limited number of studies dealing with apoptotic potential of carotenoids has been published in clinical sphere. Pro-apoptotic effects of carotenoids should be beneficial for individuals at high risk of cancer development. The article considers the utility of carotenoids in the framework of 3P medicine.

A Case of Pincer Nail Successfully Treated with Tazarotene 0.1% Gel

Pincer nail is a common condition characterized by excessive transverse nail curvature, progressively pinching the nail bed distally, resulting in cosmetic discomfort, pain and functional limitation. Treatment is difficult and often unsatisfactory. Surgical treatment performed by experienced physicians provides good outcomes. However, patients usually hesitate to undergo invasive procedures, preferring conservative treatments. Unfortunately, these mainly offer only temporary relief and recurrence rate is high. Topical tazarotene has been used in several nail conditions, but its potential remains not fully elucidated. We herewith present a case of pincer nails in a 35-year-old woman successfully treated with tazarotene 0.1% gel applied topically twice a day for 3 months who did not experience recurrence at 1-year follow-up. At 1-year follow-up, no recurrence has been observed. To our knowledge, this is the first case of pincer nails successfully treated with tazarotene 0.1% gel. With our report, we suggest topical tazarotene as a novel, effective conservative treatment of milder cases of this common, albeit disturbing condition. Although our report may not be sufficient to generalize the results, it paves the way for larger studies investigating the potential of this fast, noninvasive therapeutic agent.

Photodynamic therapy for skin cancer: How to enhance drug penetration?

Photodynamic therapy (PDT) induced by protoporphyrin IX (PpIX) has been widely used in dermatological practices such as treatment of skin cancers. Clearance rate depends on different factors such as light irradiation, skin oxygenation and drug penetration. The poor penetration of 5-aminolevulinic acid (5-ALA) with topical application is limited and restrains the production of PpIX which could restrict PDT outcomes. This review will focus on techniques already used to enhance drug penetration in human skin, and will present their results, advantages, and drawbacks. Chemical and physical pretreatments will be discussed. Chemical pre-treatments comprise of drug formulation modification, use of agents that modify the heme cycle, enhance PpIX formation, and the combination of differentiation-promoting agent prior to PDT. On the other hand, physical pretreatments affect the skin barrier by creating holes in the skin or by removing stratum corneum. To promote drug penetration, iontophoresis and temperature modulation are interesting alternative methods. Cellular mechanisms enrolled during chemical or physical pretreatments have been investigated in order to understand how 5-ALA penetrates the skin, why it is preferentially metabolized in PpIX in tumour cells, and how it could be accumulated in deeper skin layers. The objective of this review is to compare clinical trials that use innovative technology to conventional PDT treatment. Most of these pretreatments present good or even better clinical outcomes than usual PDT.

Keratinocyte Carcinomas: Current Concepts and Future Research Priorities

Cutaneous squamous cell carcinoma (cSCC) and basal cell carcinoma (BCC) are keratinocyte carcinomas, the most frequently diagnosed cancers in fair-skinned populations. Ultraviolet radiation (UVR) is the main driving carcinogen for these tumors, but immunosuppression, pigmentary factors, and aging are also risk factors. Scientific discoveries have improved the understanding of the role of human papillomaviruses (HPV) in cSCC as well as the skin microbiome and a compromised immune system in the development of both cSCC and BCC. Genomic analyses have uncovered genetic risk variants, high-risk susceptibility genes, and somatic events that underlie common pathways important in keratinocyte carcinoma tumorigenesis and tumor characteristics that have enabled development of prediction models for early identification of high-risk individuals. Advances in chemoprevention in high-risk individuals and progress in targeted and immune-based treatment approaches have the potential to decrease the morbidity and mortality associated with these tumors. As the incidence and prevalence of keratinocyte carcinoma continue to increase, strategies for prevention, including effective sun-protective behavior, educational interventions, and reduction of tanning bed access and usage, are essential. Gaps in our knowledge requiring additional research to reduce the high morbidity and costs associated with keratinocyte carcinoma include better understanding of factors leading to more aggressive tumors, the roles of microbiome and HPV infection, prediction of response to therapies including immune checkpoint blockade, and how to tailor both prevention and treatment to individual risk factors and needs.

Novel investigational therapies for onychomycosis: an update

INTRODUCTION

Onychomycosis is an infection of the nail plate that is prevalent among the ageing population. Onychomycosis is difficult to treat with low initial cure rates, high rates of relapse, and reinfection. Present treatment options include oral and topical therapies, with oral therapies yielding better results. However, there has been a greater emphasis on the development of topical antifungal therapies as they have fewer side effects and drug interactions.

AREAS COVERED

This review summarizes new and reformulated drugs. Results from in vitro studies to Phase III clinical trials are discussed. Novel drugs include: the oral azole VT-1161, the topical azole efinaconazole, the benzoxaborole tavaborole, reformulations of terbinafine P-3058 and LI-P, novel inhibitor of succinate dehydrogenase ME1111, and off-label use of tazarotene. Enhanced permeation of the morpholine amorolfine through the nail plate is also discussed using ultraviolet (UV) curable gels, and a fractional CO2 laser.

EXPERT OPINION

Novel topical antifungals and the reformulation of current antifungals have demonstrated marked improvement in nail penetration. Current research has an emphasis on topical therapies due to their minimized risk for adverse effects and higher patient demand. Nevertheless, few topical agents have surfaced in the past few years and the investigation of efficacious combination therapies may become more important.

The relevance of piroxicam for the prevention and treatment of nonmelanoma skin cancer and its precursors

Piroxicam (PXM), a nonsteroidal anti-inflammatory drug, is an enolic benzothiazine and a potent member of the oxicam series. The drug suppresses the synthesis of proinflammatory enzymes, such as cyclo-oxygenases-1 and -2 (COX-1 and 2), downregulates the production of prostaglandins (PGs) and tromboxanes, and inhibits polyamines production by blocking ornithine decarboxylase induction involved in nonmelanoma skin carcinogenesis. In addition, PXM is able to induce tumor cell apoptosis and suppresses metalloproteinase 2 activities. Skin carcinogenesis is a multistep process in which the accumulation of genetic events leads to a gradually dysplastic cellular expression, deregulation of cell growth, and carcinomatous progression. COX-1 upregulation plays a significant role in PG and vascular epidermal growth factor production supporting tumor growth. Increased level of PGs in premalignant and/or malignant cutaneous tumors is also favored by upregulation of COX-2 and downregulation of the tumor suppressor gene 15-hydroxy-prostaglandin dehydrogenase. Chemoprevention can be a hopeful approach to inhibit carcinoma occurrence before an invasive tumor develops. The chemopreventive effect of nonsteroidal anti-inflammatory drugs on nonmelanoma skin cancers has been established. In this study, we highlighted the different modalities of action of PXM on the pathogenesis of nonmelanoma skin cancer, analyzing and evaluating binding modes and energies between COX-1 or COX-2 and PXM by protein–ligand molecular docking. Our clinical experience about the local use of PXM on actinic keratoses and field cancerization is also reported, confirming its efficacy as target therapy.

Basal cell carcinoma of the skin (part 2): diagnosis, prognosis and management

Basal cell carcinoma (BCC) is a heterogeneous malignant neoplasm with different biological and clinical behaviors, often slow growing and rarely metastatic and conveying an excellent prognosis. However, BCC is the most frequent skin cancer worldwide and can cause great morbidity, as most occur in high visible areas of the body, often relapse and may invade and destroy local tissues. This review aims to present a concise and updated overview of BCC histopathology and clinical presentation and progression. We also present a summary of currently available treatment options and some of the new promising agents.

Vitamin A, cancer treatment and prevention: the new role of cellular retinol binding proteins

Retinol and vitamin A derivatives influence cell differentiation, proliferation, and apoptosis and play an important physiologic role in a wide range of biological processes. Retinol is obtained from foods of animal origin. Retinol derivatives are fundamental for vision, while retinoic acid is essential for skin and bone growth. Intracellular retinoid bioavailability is regulated by the presence of specific cytoplasmic retinol and retinoic acid binding proteins (CRBPs and CRABPs). CRBP-1, the most diffuse CRBP isoform, is a small 15 KDa cytosolic protein widely expressed and evolutionarily conserved in many tissues. CRBP-1 acts as chaperone and regulates the uptake, subsequent esterification, and bioavailability of retinol. CRBP-1 plays a major role in wound healing and arterial tissue remodelling processes. In the last years, the role of CRBP-1-related retinoid signalling during cancer progression became object of several studies. CRBP-1 downregulation associates with a more malignant phenotype in breast, ovarian, and nasopharyngeal cancers. Reexpression of CRBP-1 increased retinol sensitivity and reduced viability of ovarian cancer cells in vitro. Further studies are needed to explore new therapeutic strategies aimed at restoring CRBP-1-mediated intracellular retinol trafficking and the meaning of CRBP-1 expression in cancer patients' screening for a more personalized and efficacy retinoid therapy.

Tazarotene as alternative topical treatment for onychomycosis

Background

Distal and lateral onychomycoses are the most frequent forms of onychomycosis, causing subungual hyperkeratosis that usually limits local penetration of antimycotic drugs. Tazarotene exerts anti-inflammatory and immune-modulating activities toward both infective agents and damaged keratinocytes. Given the well-documented efficacy of tazarotene on hyperkeratotic nail psoriasis, we investigated its therapeutic use in onychomycosis.

Patients and methods

We designed a preliminary open clinical trial in patients affected by distal and lateral subungual onychomycosis of the toenails and verified the fungistatic activity of tazarotene in vitro. Fifteen patients were treated with topical tazarotene 0.1% gel once per day for 12 weeks. Mycological cultures and potassium hydroxide stains of nail samples were performed at the beginning and at the end of the study. Treatment was considered effective when clinical healing and negative mycological culture were obtained. Onycholysis, nail bed discoloration, and subungual hyperkeratosis were measured using standardized methodologies and analyzed by means of Mann–Whitney test and analysis of variance. Fungistatic activity of tazarotene was evaluated by disk diffusion assay.

Results

Six patients (40%) reached a mycological cure on target nail samples already after 4 weeks of treatment. Complete clinical healing and negative cultures were reached in all patients at week 12, with a significant improvement of all clinical parameters of the infected nails. Disk diffusion assay after 48 hours of incubation with tazarotene solution showed a central area of inhibition in all examined fungal cultures.

Conclusion

Our results documented a good clinical outcome using topical tazarotene 0.1% gel in distal and lateral subungual onychomycosis and its fungistatic activity of tazarotene in vitro. The majority of patients appeared cured at a 6-month follow-up. The efficacy and safety of tazarotene must be confirmed on a larger number of patients, although already documented in nail psoriasis patients often affected by onychomycosis.

Tazarotene induces apoptosis in human basal cell carcinoma via activation of caspase-8/t-Bid and the reactive oxygen species-dependent mitochondrial pathway

Previous studies suggest that tazarotene, a new member of the acetylenic class of RARβ/γ selective retinoids which is approved to treat a variety of skin diseases, exhibits an anti-proliferative effect in human basal cell carcinoma (BCC) by triggering caspase-dependent apoptosis. However, the detailed molecular mechanisms underlying the anti-tumor activity of tazarotene are poorly understood. This study aims at investigating the molecular mechanisms of tazarotene-induced apoptosis in human BCC cells. Our results are the first to demonstrate that tazarotene induces mitochondria-dependent cleavage of caspase-9 and -3 and PARP in BCC cells by producing reactive oxygen species (ROS) and activating caspase-8 through both ROS and death receptor signaling. These events are accompanied by a decrease in BCL-2 and BCL-xl anti-apoptotic proteins as well as by survivin and XIAP, two IAP family members. Furthermore, our results presented for the first time that tazarotene triggers a convergence of the intrinsic and extrinsic apoptotic pathways via the caspase-8-truncated Bid signaling pathway. Collectively, these data provide insights into the molecular mechanisms underlying tazarotene-induced apoptosis in human BCC cells, suggesting that this compound is a potential anti-skin cancer drug.

PI3K-AKT signaling is a downstream effector of retinoid prevention of murine basal cell carcinogenesis

Basal cell carcinoma (BCC) is the most common human cancer. We have demonstrated previously that topical application of the retinoid prodrug tazarotene profoundly inhibits murine BCC carcinogenesis via retinoic acid receptor γ-mediated regulation of tumor cell transcription. Because topical retinoids can cause adverse cutaneous effects and because tumors can develop resistance to retinoids, we have investigated mechanisms downstream of tazarotene's antitumor effect in this model. Specifically we have used (i) global expression profiling to identify and (ii) functional cell-based assays to validate the phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway as a downstream target pathway of tazarotene's action. Crucially, we have demonstrated that pharmacologic inhibition of this downstream pathway profoundly reduces murine BCC cell proliferation and tumorigenesis both in vitro and in vivo. These data identify PI3K/AKT/mTOR signaling as a highly attractive target for BCC chemoprevention and indicate more generally that this pathway may be, in some contexts, an important mediator of retinoid anticancer effects.

Advanced basal cell carcinoma

Basal cell carcinoma (BCC) is the most common skin malignancy worldwide. Ultraviolet light exposure is the best known exogenous factor in BCC development. This is also the target for primary prevention. Advanced BCC include locally advanced tumors and metastatic tumors. Prognosis is worse compared to stage I and II BCCs. Mohs or micrographically controlled surgery is the gold standard of treatment. In patients with tumors that cannot be completely removed radiotherapy was the only alternative in the past. More recently new drugs for targeted therapy of signaling pathways like sonic hedgehog or epidermal growth factor receptor became available. More small molecules are under investigation. Since the complete response rates are limited, future research has to evaluate their combination with surgery.

Extramammary Paget disease successfully treated with topical imiquimod 5% and tazarotene

Extramammary Paget disease (EMPD) is an intraepithelial adenocarcinoma usually localized in areas rich in apocrine sweat glands. Surgery remains the treatment of choice for EMPD. However, several nonsurgical treatments have been also described. Around 40 cases of EMPD treated with imiquimod 5% have been published; of these, only six correspond to nonresponses. We describe a recurrent vulvar EMPD with failure to respond to topical imiquimod 5% in monotherapy but a favorable response to its association with tazarotene.

Basal Cell Carcinoma Aggressiveness, Molecular Factors And Therapy: A Clinician Perspective

Basal cell carcinoma represents the most common skin and epithelial cancer. Most of the patients are cured by surgery. However, some cases display fullblown aggressiveness which has a dual connotation. The tumour may reach an impressive size being locally destructive while in rare cases, basal cell carcinomas may metastasize. If this agressivetumour is located on the face or neck, the surgeon is confronted with a clinical dilemma since total removal of the lesion with clear margins is impossible. Therefore, nonsurgical approaches need to be adopted in these cases. A better understand of the molecular pathways could theoretically lead to new improved therapeutic treatments. The current paper presents an update on the molecular factors with clinical importance for the treatment of basal cell carcinoma in parallel with presentation of an aggressive case as well as a review of the current therapeutic methods.

Hedgehog signaling pathway and its targets for treatment in basal cell carcinoma

Basal cell carcinoma (BCC) of the skin is the most common type of cancer and accounts for up to 40% of all cancers in the US, with a growing incidence rate over recent decades in all developed countries. Surgery is curative for most patients, although it leaves unaesthetic scars, but those that develop locally advanced or metastatic BCC require different therapeutic approaches. Furthermore, patients with BCC present a high risk of developing additional tumors. The increasing economic burden and the morbidity of BCC render primary interest in the development of targeted treatments for this disease. Among the molecular signals involved in the development of BCC, the critical role of the morphogenetic Hedgehog (Hh) pathway has become evident. This pathway is found altered and activated in almost all BCCs, both sporadic and inherited. Given the centrality of the Hh pathway in the pathophysiology of BCC, the primary efforts to identify molecular targets for the topical or systemic treatment of this cancer have focused on the Hh components. Several Hh inhibitors have been so far identified - from the first identified natural cyclopamine to the recently Food and Drug Administration-approved synthetic vismodegib - most of which target the Hh receptor Smoothened (either its function or its translocation to the primary cilium). Other molecules await further characterization (bisamide compounds), while drugs currently approved for other diseases such as itraconazole (an antimicotic agent) and vitamin D3 have been tested on BCC with encouraging results. The outcomes of the numerous ongoing clinical trials are expected to expand the field in the very near future. Further research is needed to obtain drugs targeting downstream components of the Hh pathway (eg, Gli) or to exploit combinatorial therapies (eg, with phosphatidylinositol 3-kinase inhibitors or retinoids) in order to overcome potential drug resistance.

Topical therapies for periorbital cutaneous malignancies: indications and treatment regimens

PURPOSE OF REVIEW

To present a brief review of periorbital cutaneous tumorogenesis, highlighting the steps which might be amenable to topical treatments and then discuss the use of topical agents in the management of periorbital skin malignancy.

RECENT FINDINGS

A rapid expansion in the understanding of the pathogenesis of melanoma and nonmelanoma skin cancer has allowed the development of a number of topical agents targeting specific tumor-forming processes. Topical agents have been shown to be effective in the management of periorbital skin malignancy.

SUMMARY

5-Fluorouracil and imiquimod have established roles in the management of periorbital skin malignancy. Newer agents such as ingenol mebutate, tazarotene, and diclofenac gel probably have evolving roles that require further research but show promise.

Novel investigational drugs for basal cell carcinoma

IMPORTANCE OF THE FIELD

In the United States, the annual incidence of basal cell carcinoma (BCC) is close to 1 million. Ultraviolet radiation exposure is the main risk factor; however, the availability of ever more potent sunscreens and education have not prevented the rise in BCC incidence. Therefore, concerted effects to identify novel preventive and therapeutic strategies are necessary.

AREAS COVERED IN THIS REVIEW

This article summarizes our current understanding of the etiology and molecular mechanisms of BCC tumorigenesis and discusses the preclinical and clinical studies to identify agents with anti-BCC efficacy.

WHAT THE READER WILL GAIN

The discovery that hyperactive Hh pathway signaling causes several cancers, including BCC, has spawned the development of many pharmacologic inhibitors of Hh signaling. Early clinical testing of the most advanced, GDC-0449, demonstrated impressive efficacy in patients with advanced BCC. Other promising anti-BCC chemopreventive strategies include drugs that are already FDA-approved for treating other diseases.

TAKE HOME MESSAGE

Preclinical and clinical trials with pre-existing FDA-approved drugs suggest novel uses for BCC chemoprevention and treatment. Also, new chemical entities that inhibit the Hh pathway show promise, and in combination with other drugs may provide a nonsurgical cure for this most common cancer.

Genetics of basal cell carcinoma

Basal cell carcinoma is the most common human malignancy in populations of European origin, and Australia has the highest incidence of basal cell carcinoma in the world. Great advances in the understanding of the genetics of this cancer have occurred in recent years. Mutations of the patched 1 gene (PTCH1) lead to basal cell carcinoma predisposition in Gorlin syndrome. PTCH1 is part of the hedgehog signalling pathway, and derangements within this pathway are now known to be important in the carcinogenesis of many different cancers including sporadic basal cell carcinoma. The molecular biology of the hedgehog pathway is discussed, and mouse models of basal cell carcinoma based on this pathway are explored. New developments in non-surgical treatment of basal cell carcinoma are based on this knowledge. Other genes of importance to basal cell carcinoma development include the tumour suppressor gene P53 and the melanocortin-1 receptor gene. In addition, we discuss molecules of possible importance such as the glutathione-S-transferases, DNA repair genes, cyclin-dependent kinase inhibitor 2A, Brahma and connexins. Evidence of familial aggregation of this cancer is explored and supports the possibility of genetic predisposition to this common malignancy.

Effects of narrow-band ultraviolet B and tazarotene therapy on keratinocyte proliferation and TIG3 expression

Tazarotene plus narrow-band ultraviolet B (NB-UVB) therapy has been shown to enhance the efficacy in treating patients with psoriasis, while the mechanism is not clear. The present study aims to investigate the alteration of cell proliferation and TIG3 in cultured normal human keratinocytes after NB-UVB and/or tazarotene treatment. Keratinocytes were exposed to NB-UVB, then incubated with or without tazarotene, and then cell proliferation was detected by methyl thiazoleterazolium colorimetric assay and TIG3 mRNA expression and protein production was examined by real-time reverse transcription polymerase chain reaction and immunocytochemistry, respectively. The results show that keratinocyte proliferation was inhibited and TIG3 mRNA expression and protein production were elevated by tazarotene at a dose higher than 0.1 micromol/L. In NB-UVB single irradiating groups, only 200 mJ/cm2 NB-UVB inhibited keratinocyte proliferation, and none of the irradiated groups had an effect on TIG3 expression. Moreover, tazarotene plus NB-UVB have stronger effects than those separately. These results indicate NB-UVB plus tazarotene may have synergistic effects on inhibiting keratinocyte proliferation and elevating TIG3 expression, which may have some implications for the understanding of how to treat psoriasis patients with tazarotene plus NB-UVB.

Basal cell carcinomas: attack of the hedgehog

Basal cell carcinomas (BCCs) were essentially a molecular 'black box' until some 12 years ago, when identification of a genetic flaw in a rare subset of patients who have a great propensity to develop BCCs pointed to aberrant Hedgehog signalling as the pivotal defect leading to formation of these tumours. This discovery has facilitated a remarkable increase in our understanding of BCC carcinogenesis and has highlighted the carcinogenic role of this developmental pathway when aberrantly activated in adulthood. Importantly, a phase 1 first-in-human trial of a Hedgehog inhibitor has shown real progress in halting and even reversing the growth of these tumours.

Pharmacologic retinoid signaling and physiologic retinoic acid receptor signaling inhibit basal cell carcinoma tumorigenesis

Basal cell carcinoma (BCC) is the most common human cancer. Patients with basal cell nevus syndrome (Gorlin syndrome) are highly susceptible to developing many BCCs as a result of a constitutive inactivating mutation in one allele of PATCHED 1, which encodes a tumor suppressor that is a major inhibitor of Hedgehog signaling. Dysregulated Hedgehog signaling is a common feature of both hereditary and sporadic BCCs. Recently, we showed remarkable anti-BCC chemopreventive efficacy of tazarotene, a retinoid with retinoic acid receptor (RAR) beta/gamma specificity, in Ptch1+/- mice when treatment was commenced before carcinogenic insults. In this study, we assessed whether the effect of tazarotene against BCC carcinogenesis is sustained after its withdrawal and whether tazarotene is effective against preexisting microscopic BCC lesions. We found that BCCs did not reappear for at least 5 months after topical drug treatment was stopped and that already developed, microscopic BCCs were susceptible to tazarotene inhibition. In vitro, tazarotene inhibited a murine BCC keratinocyte cell line, ASZ001, suggesting that its effect in vivo is by direct action on the actual tumor cells. Down-regulation of Gli1, a target gene of Hedgehog signaling and up-regulation of CRABPII, a target gene of retinoid signaling, were observed with tazarotene treatment. Finally, we investigated the effects of topical applications of other retinoid-related compounds on BCC tumorigenesis in vivo. Tazarotene was the most effective of the preparations studied, and its effect most likely was mediated by RARgamma activation. Furthermore, inhibition of basal RAR signaling in the skin promoted BCC carcinogenesis, suggesting that endogenous RAR signaling restrains BCC growth.

RAR and RXR modulation in cancer and metabolic disease

Retinoic acid receptors (RARs) are ligand-controlled transcription factors that function as heterodimers with retinoid X receptors (RXRs) to regulate cell growth and survival. The success of RAR modulation in the treatment of acute promyelocytic leukaemia (APL) has stimulated considerable interest in the development of RAR and RXR modulators. This has been aided by recent advances in the understanding of the biological role of RARs and RXRs and in the design of selective receptor modulators that might overcome the limitations of current drugs. Here, we discuss the challenges and opportunities for therapeutic strategies based on RXR and RAR modulators, with a focus on cancer and metabolic diseases such as diabetes and obesity.

Destruction of the orbit and globe by recurrence of basal cell carcinoma

BACKGROUND

Basal cell carcinoma (BCC) is the most common skin malignancy and represents 90% of eyelid malignancies. Of those that occur on the eyelids, most involve the lower lid. Risk factors for BCC include environmental and genetic factors. There are several clinical presentations, the 2 main forms of which are 1) nodular and 2) morpheaform (or sclerosing). Several treatment options exist, including surgical excision, cryotherapy, radiotherapy, laser surgery, chemotherapy, and photodynamic therapy. The average rate of recurrence is 5%, depending on the type of BCC, the size, the location, and therapeutic approach.

CASE REPORT

The patient described in this case report had basal cell carcinoma of the upper right lid 4 to 5 years prior to examination. At that time the patient was treated with surgical excision and radiotherapy. Subsequently, he had not received any eye care since the initial surgery to remove the malignancy. His entering complaint was drainage and an odor emanating from his right eye. The upper lid was retracted and had a lesion suspicious for BCC. The globe was keratinized, inflamed, and proptotic. He was referred to the oculoplastics service to confirm the recurrence of BCC. They found that the BCC had infiltrated the right globe and the retro-orbital region and probably invaded the adjacent bony margins. He had extensive surgery to remove the tumor and subsequent skin grafting.

CONCLUSION

BCC, when treated early, has excellent surgical outcomes. However, there is no procedure that has a zero recurrence rate. BCC, although rarely metastatic, can be invasive. This case underscores the importance of proper follow-up protocol for all surgical patients as well as patient education that reinforces the importance of follow-up care and self-monitoring on the part of the patient.

[Topical therapy of squamous cell carcinoma]

Many forms of topical chemo- and immunotherapy are employed to treat skin cancers. Topical treatment is particularly attractive for field cancerization involving multiple non-melanoma skin cancers. The dermatologist must identify such patients and lesions and provide the most suited therapy.

Novel Hedgehog pathway targets against basal cell carcinoma

The Hedgehog signaling pathway plays a key role in directing growth and patterning during embryonic development and is required in vertebrates for the normal development of many structures, including the neural tube, axial skeleton, skin, and hair. Aberrant activation of the Hedgehog (Hh) pathway in adult tissue is associated with the development of basal cell carcinoma (BCC), medulloblastoma, and a subset of pancreatic, gastrointestinal, and other cancers. This review will provide an overview of what is known about the mechanisms by which activation of Hedgehog signaling leads to the development of BCCs and will review two recent papers suggesting that agents that modulate sterol levels might influence the Hh pathway. Thus, sterols may be a new therapeutic target for the treatment of BCCs, and readily available agents such as statins (HMG-CoA reductase inhibitors) or vitamin D might be helpful in reducing BCC incidence.

Long-term establishment, characterization and manipulation of cell lines from mouse basal cell carcinoma tumors

There have been few reports of successful long-term culture of cells established from cutaneous basal cell carcinoma (BCC) tumors. Here, we describe techniques that have enabled us to establish three long-term cultures of BCC cells isolated from BCC tumors that arose in irradiated Patched 1 (Ptch1)(+/-) mice. All three cell lines showed cellular morphology similar to that of BCC tumors and could be propagated for at least 20 passages. In addition, similar to BCC tumors, all cell lines had lost the wildtype Ptch1 allele, expressed BCC molecular markers, and responded similarly to cyclopamine, a small molecule inhibitor of Hedgehog signaling. Finally, we describe an efficient electroporation technique for DNA transfection into the BCC cell lines and show that they have activated Hedgehog signaling activity, albeit at a level lower than that of murine BCCs in vivo. These data indicate that the cell lines are bona fide long-term cultures of BCC cells and that DNA plasmids can be introduced into the BCC cell lines with relatively high transfection efficiency using a modified electroporation technique.

Dermoscopy in General Dermatology

Dermoscopy improves the diagnostic accuracy in the clinical evaluation of pigmented skin lesions, but it is also useful for the assessment of vascular structures that are not visible to the naked eye. As a consequence, dermoscopy has been employed more and more for the differential diagnosis of nonpigmented skin disorders, including tumors but also inflammatory and infectious diseases. This article provides a review of the dermoscopic features seen in various nonpigmented tumoral and nontumoral skin lesions as well as the dermoscopic criteria used for monitoring skin reactions to various treatments.

Therapieoptionen bei epithelialen Hauttumoren

There has been worldwide a significant rise in the incidence of epithelial skin tumors and their precursors in the past years with an increased number of younger patients affected. The risk factors are identified. The choice of the appropriate treatment for each individual is crucial. Major consideration include high cure rate, low long-term recurrence rate and few side effects. In the following article different therapeutic approaches for actinic keratoses, Bowen's disease, basal cell carcinoma and squamous cell carcinoma are presented and analysed.