Skin Cancer

Decoding skin cancer classification: perspectives, insights, and advances through researchers' lens

Skin cancer is a significant global health concern, with timely and accurate diagnosis playing a critical role in improving patient outcomes. In recent years, computer-aided diagnosis systems have emerged as powerful tools for automated skin cancer classification, revolutionizing the field of dermatology. This survey analyzes 107 research papers published over the last 18 years, providing a thorough evaluation of advancements in classification techniques, with a focus on the growing integration of computer vision and artificial intelligence (AI) in enhancing diagnostic accuracy and reliability. The paper begins by presenting an overview of the fundamental concepts of skin cancer, addressing underlying challenges in accurate classification, and highlighting the limitations of traditional diagnostic methods. Extensive examination is devoted to a range of datasets, including the HAM10000 and the ISIC archive, among others, commonly employed by researchers. The exploration then delves into machine learning techniques coupled with handcrafted features, emphasizing their inherent limitations. Subsequent sections provide a comprehensive investigation into deep learning-based approaches, encompassing convolutional neural networks, transfer learning, attention mechanisms, ensemble techniques, generative adversarial networks, vision transformers, and segmentation-guided classification strategies, detailing various architectures, tailored for skin lesion analysis. The survey also sheds light on the various hybrid and multimodal techniques employed for classification. By critically analyzing each approach and highlighting its limitations, this survey provides researchers with valuable insights into the latest advancements, trends, and gaps in skin cancer classification. Moreover, it offers clinicians practical knowledge on the integration of AI tools to enhance diagnostic decision-making processes. This comprehensive analysis aims to bridge the gap between research and clinical practice, serving as a guide for the AI community to further advance the state-of-the-art in skin cancer classification systems.

Multi-scale feature fusion and class weight loss for skin lesion classification

Skin cancer is one of the common types of cancer. It spreads quickly and is not easy to detect in the early stages, posing a major threat to human health. In recent years, deep learning methods have attracted widespread attention for skin cancer detection in dermoscopic images. However, training a practical classifier becomes highly challenging due to inter-class similarity and intra-class variation in skin lesion images. To address these problems, we propose a multi-scale fusion structure that combines shallow and deep features for more accurate classification. Simultaneously, we implement three approaches to the problem of class imbalance: class weighting, label smoothing, and resampling. In addition, the HAM10000_RE dataset strips out hair features to demonstrate the role of hair features in the classification process. We demonstrate that the region of interest is the most critical classification feature for the HAM10000_SE dataset, which segments lesion regions. We evaluated the effectiveness of our model using the HAM10000 and ISIC2019 dataset. The results showed that this method performed well in dermoscopic classification tasks, with ACC and AUC of 94.0% and 99.3%, on the HAM10000 dataset and ACC of 89.8% for the ISIC2019 dataset. The overall performance of our model is excellent in comparison to state-of-the-art models.

Anti-aging Strategies and Topical Delivery of Biopolymer-based Nanocarriers for Skin Cancer Treatment

Environmental factors like UV radiation and epigenetic changes are significant factors for skin cancer that trigger early aging. This review provides essential information on cancer development concerning aging, the receptors involved, and the therapeutic targets. Biopolymers like polysaccharide, polyphenols, proteins, and nucleic acid plays a vital role in the regulation of normal cell homeostasis. Therefore, it is pertinent to explore the role of biopolymers as antiaging formulations and the possibility of these formulations being used against cancer via topical administrations. As UV radiation is one of the predominant factors in causing skin cancer, the association of receptors between aging and cancer indicated that insulin receptor, melatonin receptor, toll-like receptor, SIRT 1 receptor, tumor-specific T cell receptor and mitochondria-based targeting could be used to direct therapeutics for suppression of cancer and prevent aging. Biopolymer-based nanoformulations have tremendously progressed by entrapment of drugs like curcumin and resveratrol which can prevent cancer and aging simultaneously. Certain protein signaling or calcium and ROS signaling pathways are different for cancer and aging. The involvement of mitochondrial DNA mutation along with telomere shortening with a change in cellular energetics leading to genomic instability in the aging process can also induce mitochondrial dysfunction and epigenetic alterations leading to skin cancer. Therefore, the use of biopolymers as a topical supplement during the aging process can result in the prevention of cancer.

An Ensemble of Transfer Learning Models for the Prediction of Skin Cancers with Conditional Generative Adversarial Networks

Skin cancer is one of the most severe forms of the disease, and it can spread to other parts of the body if not detected early. Therefore, diagnosing and treating skin cancer patients at an early stage is crucial. Since a manual skin cancer diagnosis is both time-consuming and expensive, an incorrect diagnosis is made due to the high similarity between the various skin cancers. Improved categorization of multiclass skin cancers requires the development of automated diagnostic systems. Herein, we propose a fully automatic method for classifying several skin cancers by fine-tuning the deep learning models VGG16, ResNet50, and ResNet101. Prior to model creation, the training dataset should undergo data augmentation using traditional image transformation techniques and Generative Adversarial Networks (GANs) to prevent class imbalance issues that may lead to model overfitting. In this study, we investigate the feasibility of creating dermoscopic images that have a realistic appearance using Conditional Generative Adversarial Network (CGAN) techniques. Thereafter, the traditional augmentation methods are used to augment our existing training set to improve the performance of pre-trained deep models on the skin cancer classification task. This improved performance is then compared to the models developed using the unbalanced dataset. In addition, we formed an ensemble of finely tuned transfer learning models, which we trained on balanced and unbalanced datasets. These models were used to make predictions about the data. With appropriate data augmentation, the proposed models attained an accuracy of 92% for VGG16, 92% for ResNet50, and 92.25% for ResNet101, respectively. The ensemble of these models increased the accuracy to 93.5%. A comprehensive discussion on the performance of the models concluded that using this method possibly leads to enhanced performance in skin cancer categorization compared to the efforts made in the past.

Transfer Learning with Ensembles of Deep Neural Networks for Skin Cancer Detection in Imbalanced Data Sets

Early diagnosis plays a key role in prevention and treatment of skin cancer. Several machine learning techniques for accurate detection of skin cancer from medical images have been reported. Many of these techniques are based on pre-trained convolutional neural networks (CNNs), which enable training the models based on limited amounts of training data. However, the classification accuracy of these models still tends to be severely limited by the scarcity of representative images from malignant tumours. We propose a novel ensemble-based convolutional neural network (CNN) architecture where multiple CNN models, some of which are pre-trained and some are trained only on the data at hand, along with auxiliary data in the form of metadata associated with the input images, are combined using a meta-learner. The proposed approach improves the model’s ability to handle limited and imbalanced data. We demonstrate the benefits of the proposed technique using a dataset with 33,126 dermoscopic images from 2056 patients. We evaluate the performance of the proposed technique in terms of the F1-measure, area under the ROC curve (AUC-ROC), and area under the PR-curve (AUC-PR), and compare it with that of seven different benchmark methods, including two recent CNN-based techniques. The proposed technique compares favourably in terms of all the evaluation metrics.

ABO blood group and skin cancers

Beside the role of ABO group in immunohaematology, there is accumulating evidence that the ABO blood group also plays a key role in various human disorders. The interest in blood groups and their association with disease stems from the awareness that blood group antigens are incredibly important components in the process of cell maturation and control. Studies have indicated a link between cancer and the ABO blood group. The appearance or disappearance of blood type antigens is now considered a hallmark of malignancy in many common cancers. Several tumour markers are in fact known blood group antigens. The aim of this review is to describe the history and possible functions of the ABO group and then summarize the association between blood groups and skin cancers.

Improving the Antitumor Activity and Bioavailability of Sonidegib for the Treatment of Skin Cancer

Throughout the United States and the world, skin cancer is the most frequent form of cancer. Sonidegib (SNG) is a hedgehog inhibitor that has been used for skin cancer treatment. However, SNG has low bioavailability and is associated with resistance. The focus of this work is to enhance bioavailability, anti-tumor efficacy and targeting of SNG via developing ethosome gel as a potential treatment for skin cancer. SNG-loaded ethosomes formulation was prepared and characterized in vitro by %entrapment efficiency (%EE), vesicle size, morphology, %release and steady-state flux. The results showed that the prepared formulation was spherical nanovesicles with a %EE of 85.4 ± 0.57%, a particle size of 199.53 ± 4.51 nm and a steady-state flux of 5.58 ± 0.08 µg/cm2/h. In addition, SNG-loaded ethosomes formulation was incorporated into carbopol gel to study the anti-tumor efficacy, localization and bioavailability in vivo. Compared with oral SNG, the formulation showed 3.18 times higher relative bioavailability and consequently significant anti-tumor activity. In addition, this formulation showed a higher rate of SNG penetration in the skin's deep layers and passive targeting in tumor cells. Briefly, SNG-loaded ethosome gel can produce desirable therapeutic benefits for treatment of skin cancer.

Multifunctional Photostable Nanocomplex of ZnO Quantum Dots and Avobenzone via the Promotion of Enolate Tautomer

Ideal multifunctional ultraviolet radiation (UVR) absorbents with excellent photostability, high molar absorptivity, broadband UVR screening, and desired skin sensorial properties remain a significant challenge for the sunscreen industry. The potential of the nanocomplex (NCx) formed by microwave synthesis of ZnO quantum dots (QDs) in the presence of Avobenzone (Av) for achieving these goals is reported. The NCx exhibits unique synergy between ZnO QD and Av components, which enhances the photostability and molar absorptivity, extends UVA filtering range, and provides a visible emission that matches the typical human in vivo skin emission color. Density functional theory (DFT) and time-dependent DFT calculations of ZnO-Av hybrid structures and comparison of their spectroscopic features with experiments suggest that ZnO QDs catalyze the formation of highly photostable surface enolate species via aldol condensation reaction. The combination of experiments and computations used in this study can advance the science and technology of photoprotection.

Cancer incidence among male military and civil pilots and flight attendants: an analysis on published data

Flight personnel are exposed to cosmic ionizing radiation, chemicals (fuel, jet engine exhausts, cabin air pollutants), electromagnetic fields from cockpit instruments, and disrupted sleep patterns. Only recently has cancer risk among these workers been investigated. With the aim of increasing the precision of risk estimates of cancer incidence, follow-up studies reporting a standardized incidence ratio for cancer among male flight attendants, civil and military pilots were obtained from online databases and analysed. A meta-analysis was performed by applying a random effect model, obtaining a meta-standardized incidence ratio (SIR), and 95% confidence interval (CI). In male cabin attendants, and civil and military pilots, meta-SIRs were 3.42 (CI=1.94-6.06), 2.18 (1.69-2.80), 1.43 (1.09-1.87) for melanoma; and 7.46 (3.52-15.89), 1.88 (1.23-2.88), 1.80 (1.25-2.58) for other skin cancer, respectively. These tumors share as risk factors, ionizing radiation, recreational sun exposure and socioeconomic status. The meta-SIRs are not adjusted for confounding; the magnitude of risk for melanoma decreased when we corrected for socioeconomic status. In civil pilots, meta-SIR was 1.47 (1.06-2.05) for prostate cancer. Age (civil pilots are older than military pilots and cabin attendants) and disrupted sleep pattern (entailing hyposecretion of melatonin, which has been reported to suppress proliferative effects of androgen on prostate cancer cells) might be involved. In male cabin attendants, meta-SIR was 21.5 (2.25-205.8) for Kaposi’s sarcoma and 2.49 (1.03-6.03) for non-Hodgkin’s lymphoma. AIDS, which was the most frequent single cause of death in this occupational category, likely explains the excess of the latter two tumors.

[Genetic diversity and immunological characteristics of malignant melanoma: the therapeutic spectrum]

Malignant melanoma, originating from pigment cells, is a highly aggressive tumour affecting patients of any age group. Its incidence is rapidly growing. The most common form can be easily diagnosed by any physician. There are some well-known genetic (skin-, eye-, hair colour, naevi, melanoma in the personal/family history) and environmental (ultraviolet radiation) predisposing factors. Treatment is based on early diagnosis and excision. When metastasis occurs, the traditional chemo- and radiotherapy gives a low response rate. Recently some newly approved targeted therapies and immunomodulant drugs have become available. This review focuses on the classification and novel therapeutic approaches of malignant melanoma to provide guidance to clinicians.

Polymorphous light eruption: clinic aspects and pathogenesis

Polymorphous light eruption is an immunologically mediated photodermatosis with high prevalence, particularly among young women in temperate climates, characterized by pruritic skin lesions of variable morphology, occurring in spring or early summer on sun-exposed body sites. A resistance to ultraviolet radiation (UVR)-induced immunosuppression and a subsequent delayed-type hypersensitivity response to a photoantigen have been suggested as key factors in the disease. Molecular and immunologic disturbances associated with disease pathogenesis include a failure of skin infiltration by neutrophils and other regulatory immune cells on UVR exposure linked to a disturbed cytokine microenvironment. Standard management is based on prevention.

The South Asian genome

The genetic sequence variation of people from the Indian subcontinent who comprise one-quarter of the world's population, is not well described. We carried out whole genome sequencing of 168 South Asians, along with whole-exome sequencing of 147 South Asians to provide deeper characterisation of coding regions. We identify 12,962,155 autosomal sequence variants, including 2,946,861 new SNPs and 312,738 novel indels. This catalogue of SNPs and indels amongst South Asians provides the first comprehensive map of genetic variation in this major human population, and reveals evidence for selective pressures on genes involved in skin biology, metabolism, infection and immunity. Our results will accelerate the search for the genetic variants underlying susceptibility to disorders such as type-2 diabetes and cardiovascular disease which are highly prevalent amongst South Asians.

Relationships between skin cancers and blood groups--link between non-melanomas and ABO/Rh factors

BACKGROUND

This investigation focused on possible relationships between skin cancers and ABO/Rh blood groups.

MATERIALS AND METHODS

Between January 2005 and December 2012, medical data of 255 patients with skin cancers who were admitted to Kayseri Training and Research Hospital, Radiation Oncology and Plastic Surgery Outpatient Clinics were retrospectively analyzed. Blood groups of these patients were recorded. The control group consisted of 25701 healthy volunteers who were admitted to Kayseri Training and Research Hospital, Blood Donation Center between January 2010 and December 2011. The distribution of the blood groups of the patients with skin cancers was compared to the distribution of ABO/Rh blood groups of healthy controls. The association of the histopathological subtypes of skin cancer with the blood groups was also investigated.

RESULTS

Of the patients, 50.2% had A type, 26.3% had O type, 16.1% had B type, and 7.5% had AB blood group with a positive Rh (+) in 77.3%. Of the controls, 44.3% had A type, 31.5% had 0 type, 16.1% had B type, and 8.1% had AB blood group with a positive Rh (+) in 87.8%. There was a statistically significant difference in the distribution of blood groups and Rh factors (A Rh (-) and 0 Rh positive) between the patients and controls. A total of 36.8% and 20.4% of the patients with basal cell carcinoma (BCC) had A Rh (+) and B Rh (+), respectively, while 39.2% and 27.6% of the controls had A Rh (+) and B Rh (+), respectively. A significant relationship was observed between the patients with BCC and controls in terms of A Rh (-) (p=0.001).

CONCLUSION

Our study results demonstrated that there is a significant relationship between non-melanoma skin cancer and ABO/Rh factors.

Distribution of Basal cell carcinoma and squamous cell carcinoma by facial esthetic unit

Background

The most common cutaneous malignant masses are basal cell carcinoma (BCC) and squamous cell carcinoma. The predominant site of a malignant mass is the face, which has many opportunities to be exposed to ultraviolet radiation. However the predilection sites of malignant masses have been equivocal due to the use of general regions, rather than anatomical landmarks, in surveys. A facial esthetic unit is an anatomical site classified as an area of similar facial contour characteristics that can be distinguished from other areas. The purpose of this study is to determine widely accepted anatomical landmarks using the esthetic unit.

Methods

We retrospectively analyzed 118 cases of malignant masses in our clinic from January 2005 to October 2012. We evaluated the patients' age, gender, and predilection site of the malignant mass by esthetic unit through pathology, medical records and patient photographs. We mapped the occurrence site of the malignant mass on schematic drawings of the esthetic units.

Results

Most of the malignant masses were BCC. The ratio of males to females was 1:1.41. The frequent predilection site of a malignant mass was on the nasal unit (33.1%), followed by the buccal unit (11.0%). Primary closure was the most common method of repairing a surgical defect (38.9%), followed by a local flap (35.5%).

Conclusions

This review described the relationship between clinical characteristics and esthetic units by proposing objective predilection sites for malignant masses, which can be used commonly as a framework in the study of malignant masses by unifying equivocal occurrence sites.

Molecular signatures of basal cell carcinoma susceptibility and pathogenesis: a genomic approach

Gene expression profiling can be useful for phenotypic classification, investigation of functional pathways, and to facilitate the search for disease risk genes through the integration of transcriptional data with available genomic information. To enhance our understanding of the genetic and molecular basis of basal cell carcinoma (BCC) we performed global gene expression analysis to generate a disease-associated transcriptional profile. A gene signature composed of 331 differentially expressed genes (DEGs) was generated from comparing 4 lesional and 4 site-matched control samples using Affymetrix Human Genome U95A microarrays. Hierarchical clustering based on the obtained gene signature separated the samples into their corresponding phenotype. Pathway analysis identified several significantly overrepresented pathways including PPAR-γ signaling, TGF-β signaling and lipid metabolism, as well as confirmed the importance of SHH and p53 in the pathogenesis of BCC. Comparison of our microarray data with previous microarray studies revealed 13 DEGs overlapping in 3 studies. Several of these overlapping genes function in lipid metabolism or are components of the extracellular matrix, suggesting the importance of these and related pathways in BCC pathogenesis. BCC-associated DEGs were mapped to previously reported BCC susceptibility loci including 1p36, 1q42, 5p13.3, 5p15 and 12q11-13. Our analysis also revealed transcriptional 'hot spots' on chromosome 5 which help to confirm (5p13 and 5p15) and suggest novel (5q11.2-14.3, 5q22.1-23.3 and 5q31-35.3) disease susceptibility loci/regions. Integrating microarray analyses with reported genetic information helps to confirm and suggest novel disease susceptibility loci/regions. Identification of these specific genomic and/or transcriptional targets may lead to novel diagnostic and therapeutic modalities.

Analysis of Tp53 codon 72 polymorphisms, Tp53 mutations, and HPV infection in cutaneous squamous cell carcinomas

Background

Non-melanoma skin cancers are one of the most common human malignancies accounting for 2–3% of tumors in the US and represent a significant health burden. Epidemiology studies have implicated Tp53 mutations triggered by UV exposure, and human papilloma virus (HPV) infection to be significant causes of non-melanoma skin cancer. However, the relationship between Tp53 and cutaneous HPV infection is not well understood in skin cancers. In this study we assessed the association of HPV infection and Tp53 polymorphisms and mutations in lesional specimens with squamous cell carcinomas.

Methods

We studied 55 cases of histologically confirmed cutaneous squamous cell carcinoma and 41 controls for the presence of HPV infection and Tp53 genotype (mutations and polymorphism).

Results

We found an increased number of Tp53 mutations in the squamous cell carcinoma samples compared with perilesional or control samples. There was increased frequency of homozygous Tp53-72R polymorphism in cases with squamous cell carcinomas, while the Tp53-72P allele (Tp53-72R/P and Tp53-72P/P) was more frequent in normal control samples. Carcinoma samples positive for HPV showed a decreased frequency of Tp53 mutations compared to those without HPV infection. In addition, carcinoma samples with a Tp53-72P allele showed an increased incidence of Tp53 mutations in comparison carcinomas samples homozygous for Tp53-72R.

Conclusions

These studies suggest there are two separate pathways (HPV infection and Tp53 mutation) leading to cutaneous squamous cell carcinomas stratified by the Tp53 codon-72 polymorphism. The presence of a Tp53-72P allele is protective against cutaneous squamous cell carcinoma, and carcinoma specimens with Tp53-72P are more likely to have Tp53 mutations. In contrast Tp53-72R is a significant risk factor for cutaneous squamous cell carcinoma and is frequently associated with HPV infection instead of Tp53 mutations. Heterozygosity for Tp53-72R/P is protective against squamous cell carcinomas, possibly reflecting a requirement for both HPV infection and Tp53 mutations.

Analysis of the dynamics of the incidence rate for malignant skin neoplasms among the populationresiding in the impact zone of a large-scale nuclear enterprise

The study involved an analysis of the dynamics of dermatological and oncological diseases [epithelial malignant skin neoplasms (С44), malignant skin melanoma (С43)] conducted among the population of the town of Seversk in 1970- 2009. A growth in the incidence rate of malignant skin neoplasms in 2000-2009 was revealed; it was established that such data exceed similar indices for the Tomsk region

The protective role of melanin against UV damage in human skin

Human skin is repeatedly exposed to UVR that influences the function and survival of many cell types and is regarded as the main causative factor in the induction of skin cancer. It has been traditionally believed that skin pigmentation is the most important photoprotective factor, as melanin, besides functioning as a broadband UV absorbent, has antioxidant and radical scavenging properties. Besides, many epidemiological studies have shown a lower incidence for skin cancer in individuals with darker skin compared to those with fair skin. Skin pigmentation is of great cultural and cosmetic importance, yet the role of melanin in photoprotection is still controversial. This article outlines the major acute and chronic effects of UVR on human skin, the properties of melanin, the regulation of pigmentation and its effect on skin cancer prevention.

DNA damage, apoptosis and langerhans cells--Activators of UV-induced immune tolerance

Solar UVR is highly mutagenic but is only partially absorbed by the outer stratum corneum of the epidermis. UVR can penetrate into the deeper layers of the epidermis, depending on melanin content, where it induces DNA damage and apoptosis in epidermal cells, including those in the germinative basal layer. The cellular decision to initiate either cellular repair or undergo apoptosis has evolved to balance the acute need to maintain skin barrier function with the long-term risk of retaining precancerous cells. Langerhans cells (LCs) are positioned suprabasally, where they may sense UV damage directly, or indirectly through recognition of apoptotic vesicles and soluble mediators derived from surrounding keratinocytes. Apoptotic vesicles will contain UV-induced altered proteins that may be presented to the immune system as foreign. The observation that UVR induces immune tolerance to skin-associated antigens suggests that this photodamage response has evolved to preserve the skin barrier by protecting it from autoimmune attack. LC involvement in this process is not clear and controversial. We will highlight some basic concepts of photobiology and review recent advances pertaining to UV-induced DNA damage, apoptosis regulation, novel immunomodulatory mechanisms and the role of LCs in generating antigen-specific regulatory T cells.

Skin cancer in skin of color

Skin cancer is less common in persons with skin of color than in light-skinned Caucasians but is often associated with greater morbidity and mortality. Thus, it is crucial that physicians become familiar with skin cancer in persons of color so as to maximize the likelihood of early detection of these tumors. In dark-skinned ethnic groups, squamous cell carcinoma is most common; squamous cell carcinoma and melanoma usually occur on nonsun-exposed sites; and ultraviolet radiation is not an important etiologic factor for skin cancer with the exception of basal cell carcinoma. Races of intermediate pigmentation, such as Hispanics and Asians, share epidemiologic and clinical features of dark-skinned ethnic groups and Caucasians. Skin cancers pose a significant risk in skin of color and clinicians should focus on preventive measures in these groups such as regular skin exams, self-examination, public education, and screening programs.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with the epidemiology and unique clinical features of skin cancer in skin of color and be aware of strategies to prevent skin cancer in skin of color.

The association between non-melanoma skin cancer and a young dimorphic Alu element within the major histocompatibility complex class I genomic region

A non-melanoma skin cancer (NMSC) susceptibility locus within the major histocompatibility complex (MHC) class I region was previously identified telomeric of the HLA-C gene using high-density microsatellite markers. Here, we have extended the previous microsatellite study by using the same DNA samples obtained from 154 NMSC patients and 213 normal controls from the town of Busselton in Western Australia and examined the relationship between five polymorphic Alu insertions (POALINs) within the MHC class I region and their association with NMSC. The genotype distribution of the AluyTF insertion that is located within the NMSC susceptibility region telomeric of the HLA-C gene was significantly increased according to the Fisher's exact test in the NMSC patients, and it was not in Hardy-Weinberg equilibrium in the control group. There was no difference between the cancer patients and controls for the genotypes of the AluyMICB locus within intron 1 of the MICB gene and the other three POALINs (AluyHJ, AluyHG and AluyHF) that are located within the genomic region of the HLA-A, -G and -F gene cluster. The test for significant linkage disequilibrium for 10 pairs of POALIN loci and estimations of two locus POALIN haplotype frequencies also revealed AluyTF differences between the cases and controls. In conclusion, the MHC class I POALIN, AluyTF, that is located within the NMSC susceptibility locus and near the HLA-C gene was strongly associated with NMSC. This finding, using five different polymorphic Alu insertion markers, supports the previous microsatellite association study that one or more genes located in close proximity to the AluyTF insertion has a potential role in NMSC.

Ultraviolet A exposure alters adhesive properties of mouse melanoma cells

BACKGROUND

We have examined whether ultraviolet A (UVA) irradiation could alter adhesive properties of melanoma cells. As an experimental in vitro model, we have used C57BL/6 mouse-derived B16- F1 and B16-F10 melanoma cell lines and the syngeneic MS-1 endothelial cell line.

METHOD/RESULT

The melanoma cells were exposed to different doses of UVA irradiation. We have determined that a single dose of UVA at 8 and 12 J/cm(2) causes an 88% (P<0.001) and a 32% (P<0.05) increase in B16-F1 melanoma cell adhesiveness to the non-irradiated endothelial monolayer, respectively. The peak of the response was 24 h after the irradiation. The UVA dose of 8 J/cm(2) delivered in four doses separated by 1 h intervals (4 x 2 J/cm(2)) had led to a caused 149% (P<0.001) increase of B16-F1 melanoma adhesiveness already at 1 h after the last dose of UVA. Besides the induction of increase in the melanoma-endothelial cell adhesion, UVA exposure has induced a rapid decline (1 h after exposure) in homotypic melanoma-melanoma cell adhesion (clustering). The clustering decline of B16-F1 cells with a single dose of UVA at 8 J/cm(2) was by 61% (P<0.05) and by 35% (P<0.05) with 4 x 2 J/cm(2). Pilot experiments have shown that the changes of the adhesive properties of melanoma cells were accompanied by an increase in N-cadherin expression and a decline in E-cadherin expression. Such a change in cadherin expression profile has been shown to be an indicator of the increased metastatic potential.

CONCLUSION

Our results suggest that UVA radiation appears to alter the adhesive properties of melanoma cells in vitro, by diminishing the melanoma-melanoma adhesion and by increasing melanoma adhesion to the endothelium. This suggests that UVA exposure might increase the metastatic capability of the melanoma cells.

The Pitfalls of Treating All Actinic Keratoses as Squamous Cell Carcinomas

The greatest difficulties in managing a patient with numerous actinic keratoses is deciding the order in which to treat the specific lesions and what modality to use. The patient with a small number of lesions is probably most conveniently and cost effectively treated using destructive techniques like cryosurgery, electrodesiccation or photodynamic therapy with lasers. However, patients with large numbers of lesions are probably best managed using a topical chemotherapy agent, like 5-florouracil or imiquimod. If the patient's health insurance company limits coverage for the treatment of a specific number AK's per visit, it may be most prudent and logical to begin treatment of the largest or most rapidly growing AK's first and continue treatment of remaining lesions at subsequent visits until all lesions have been eradicated.

Infiltrating basal cell carcinoma of the neck 34 years after irradiation of an haemangioma in early childhood. A case-report

A case of a 34-year-old Caucasian male is presented with a basal cell carcinoma deeply infiltrating the structures of the neck, including skeletal muscles and reaching the parotid gland. Radical surgical removal under meticulous histological control was performed. 18 months postoperatively, the patient is still free of recurrence. Thirty years ago the patient had undergone radiotherapy for an infantile haemangioma of the skin of the neck. The effects of this treatment when given in childhood in the aetiology of a basal cell carcinoma are discussed.

Nonmelanoma Skin Cancer

Each year, there are as many cases of nonmelanoma skin cancer as all other cancers combined. Although there is relatively low attributable mortality, the morbidity and expense of treatment is significant. Unlike many other malignancies, host and environmental factors relevant to the pathophysiology have been clearly demonstrated. Surgical ablation remains the mainstay of treatment.

Descriptive epidemiology of basal cell carcinoma and cutaneous squamous cell carcinoma in Soria (north-eastern Spain) 1998-2000: a hospital-based survey

INTRODUCTION

Better knowledge of the epidemiology of basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC) will allow the development of more effective diagnostic and preventive measures.

MATERIAL AND METHODS

We have reviewed the clinical records of patients from the 'Hospital General de Soria' who were diagnosed with BCC and/or SCC (lower lip included) by histopathology between 1 January 1998 and 31 December 2000. Recurrences and diagnostic duplicities (tumours first biopsied and then excised) were excluded.

RESULTS

The mean age was 71.4 years for BCC subjects and significantly older, 77.3 years, for SCC subjects. Photoexposed skin areas accounted for 92.6% and 93.8% of BCC and SCC tumours, respectively. The crude incidence rate for the population of 100 000 was 148.27 for BCC and 58.24 for SCC. The age-adjusted incidence rate (adjusted for world standard population) was 57.97 and 17.87 years, respectively. Subjects with superficial BCC were significantly younger than the rest of the BCC patients and their tumours were located on non-photoexposed skin. The ears and dorsum of the hands were the almost exclusive locations of SCC.

CONCLUSIONS

Our results should be compared with those to be obtained in future years to determine trends in the descriptive epidemiology of BCC and SCC.

Mice with genetically determined high susceptibility to ultraviolet (UV)-induced immunosuppression show enhanced UV carcinogenesis

To assess the premise that genetically determined differences in susceptibility to UV-induced immunosuppression are reflected in UV carcinogenesis, we investigated UV skin cancer induction in two strains of reciprocal F1 hybrid mice CB6F1 males with high susceptibility to UV immunosuppression and a BALB/c X-chromosome and B6CF1 males with low susceptibility to UV immunosuppression and a C57BL/6 X-chromosome. Four experimental groups comprising both strains treated three times weekly with two UV regimens (daily doses incremented from 2.25 to 6 or 4.5 to 12 kJ per m2) were monitored for skin tumor development. Survival without a skin tumor differed over the four groups (p < 0.0001) and differed according to UV regimen within each strain (p < 0.0005). Differences between strains were significant for the higher dose (p = 0.03) but not for the lower dose (p = 0.19) of UV, suggesting a dose-strain interaction. Comparing the higher UV dose regimen to the lower UV dose regimen within a strain at three reference points, tumor-free survival was reduced significantly more (p < 0.05) in the CB6F1 mice than in the B6CF1 mice. Histologic assessment of all tumors revealed fibrosarcomas, squamous carcinomas, and mixed tumors. Immunohistochemistry of the mixed tumors for vimentin, keratin, and E-cadherin confirmed the presence of squamous and fibrosarcomatous elements. The enhanced susceptibility to UV carcinogenesis of CB6F1 males treated with the higher UV protocol was attributable to a significantly enhanced proportion (p < 0.005) of mixed tumors. Analysis of the data by comparing the proportion of animals tumor free at three reference time points confirmed a dose-strain interaction only in the development of mixed tumors, putatively the malignantly advanced carcinomas (p < 0.03). A dose-strain interaction was also observed for systemic UV immunosuppression of contact hypersensitivity (p < 0.025). These findings support the concept that genetic differences in susceptibility to UV-induced immunosuppression may be a risk factor for skin cancer.

Prevention of immunosuppression by sunscreens in humans is unrelated to protection from erythema and dependent on protection from ultraviolet a in the face of constant ultraviolet B protection

Sunscreens have been advocated as an important means of preventing skin cancer. Ultraviolet radiation induced immunosuppression is recognized as an important event in skin cancer development, yet the effectiveness of sunscreens in protecting the human immune system from ultraviolet radiation (i.e. ultraviolet radiation) is still unclear. The only currently accepted method of sunscreen rating is the sun protection factor system based on the prevention of erythema. We determined immune protection factors for six commercially available sunscreens using a nickel contact hypersensitivity model in humans. Both sun protection factor and immune protection factor testing was performed using the same solar simulated ultraviolet radiation source and dose-responses were used to determine endpoints both with and without sunscreens. We found that the immune protection factor did not correlate with the sun protection factor; however, immune protection factor was significantly correlated to the ultraviolet A protective capability of the sunscreens, indicating that sunscreen protection from ultraviolet A is important for the prevention of ultraviolet immunosuppression, when there is constant ultraviolet B protection. We recommend that sunscreens should be rated against their immune protective capability to provide a better indication of their ability to protect against skin cancer.

Basal cell carcinoma, squamous cell carcinoma and melanoma of the skin: analysis of the Singapore Cancer Registry data 1968-97

BACKGROUND

There has been an alarming recent increase in skin cancer incidence among fair-skinned populations. Information from Asian populations is less readily available.

OBJECTIVES

This study examines time trends and ethnic differences of skin cancers among Asians in Singapore.

METHODS

Data from 1968 to 1997 was obtained from the Singapore Cancer Registry, a population-based registry. Age-standardized incidence rates (ASRs) and age-adjusted average annual percentage change, using the Poisson regression model, were calculated.

RESULTS

A total of 2650 basal cell carcinomas (BCCs), 1407 squamous cell carcinomas (SCCs) and 281 melanomas were reported. There was an overall increase of skin cancer from 6.0 per 100000 person years (1968-72) to 8.9 per 100000 person years (1993-97). BCC incidence increased 3% annually, melanoma remained constant, and SCC decreased 0.9% annually. BCC ASRs were highest among Chinese, then Malays and Indians. A similar pattern was noted for SCC and melanomas.

CONCLUSIONS

The incidence rates of skin cancer increased in Singapore during the period 1968-97. Fairer-skinned Chinese had a higher incidence of skin cancer.

The influence of painful sunburns and lifetime sun exposure on the risk of actinic keratoses, seborrheic warts, melanocytic nevi, atypical nevi, and skin cancer

Painful sunburns are implicated in the pathogenesis of squamous cell carcinoma, basal cell carcinoma, and malignant melanoma. Chronic exposure to ultraviolet radiation is known as the most important risk factor for the development of actinic keratoses and squamous cell carcinoma. The purpose of the study was to assess the effect of painful sunburns and lifetime sun exposure on the development of actinic keratoses and seborrheic warts in relation to the development of squamous cell carcinoma and basal cell carcinoma, and on the development of melanocytic nevi and atypical nevi in relation to the development of malignant melanoma. We made use of a cohort of 966 individuals who participated in a case-control study to investigate environmental and genetic risk factors for skin cancer. Exposure measurements for sunlight were collected and actinic keratoses, seborrheic warts, melanocytic nevi, and atypical nevi were counted. Relative risks were estimated using exposure odds ratios from cross-tabulation. Multivariate logistic regression was used to adjust for potential confounders. The recall of painful sunburns before the age of 20 y was associated with an increased risk of squamous cell carcinoma, nodular basal cell carcinoma, and multifocal superficial basal cell carcinoma as well as actinic keratoses. Odds ratios with 95% confidence intervals adjusted for age, sex, and skin type were 1.5 (0.97; 2.3); 1.6 (1.1; 2.2); 2.6 (1.7; 3.8); and 1.9 (1.4; 2.6) for the three types of nonmelanoma skin cancer and actinic keratoses, respectively. Painful sunburns before the age of 20 y were also associated with an increased risk of malignant melanoma and the development of its precursors, melanocytic nevi and atypical nevi. Odds ratios with 95% confidence intervals adjusted for age, sex, and skin type were 1.4 (0.86; 2.1); 1.5 (1.1; 2.0); and 1.4 (0.88; 2.3) for malignant melanoma and the two types of precursors, respectively. Lifetime sun exposure was predominantly associated with an increased risk of squamous cell carcinoma (p-value for trend=0.03) and actinic keratoses (p-value for trend <0.0001) and to a lesser degree with the two types of basal cell carcinoma. By contrast, lifetime sun exposure appeared to be associated with a lower risk of malignant melanoma, despite the fact that lifetime sun exposure did not diminish the number of melanocytic nevi or atypical nevi. Neither painful sunburns nor lifetime sun exposure were associated with an increased risk of seborrheic warts.

Ultraviolet radiation and cutaneous malignant melanoma

Recent years have seen a steady rise in the incidence of cutaneous malignant melanoma worldwide. Although it is now appreciated that the key to understanding the process by which melanocytes are transformed into malignant melanoma lies in the interplay between genetic factors and the ultraviolet (UV) spectrum of sunlight, the nature of this relation has remained obscure. Recently, prospects for elucidating the molecular mechanisms underlying such gene-environment interactions have brightened considerably through the development of UV-responsive experimental animal models of melanoma. Genetically engineered mice and human skin xenografts constitute novel platforms upon which to build studies designed to elucidate the pathogenesis of UV-induced melanomagenesis. The future refinement of these in vivo models should provide a wealth of information on the cellular and genetic targets of UV, the pathways responsible for the repair of UV-induced DNA damage, and the molecular interactions between melanocytes and other skin cells in response to UV. It is anticipated that exploitation of these model systems will contribute significantly toward the development of effective approaches to the prevention and treatment of melanoma.

Matrix metalloproteinases in tumor progression: focus on basal and squamous cell skin cancer

Many normal biological processes, such as reproduction, fetal development and wound healing, are critically dependent on controlled degradation of extracellular matrix (ECM) macromolecules. However, excessive degradation of matrix components occurs in pathologic tissue destruction, e.g. in atherosclerosis, rheumatoid arthritis, and cancer. Matrix metalloproteinases (MMPs) are degradative enzymes that play an important role in all aspects of tumor progression by enhancing tumor-induced angiogenesis and destroying local tissue architecture and basement membranes to allow tumor invasion and metastasis. Efficient breakdown of the ECM surrounding invasive cancer islands involves interplay between tumor cells, stromal cells, and inflammatory cells, all of which express a distinct set of MMPs. Besides the classical role of MMPs in degradation of ECM, MMPs may also indirectly influence the tumor microenvironment through the release of growth factors, cryptic sites or angiogenic factors, or through the generation of matrix fragments that inhibit tumor cell proliferation, migration and angiogenesis. This makes the contribution of MMPs to tumorigenesis much more complex than initially thought. Currently, a number of clinical studies have focused on testing MMP inhibitors as potential antineoplastic agents. In this review we discuss the present role of MMPs in the development and progression of cancer, focusing on non-melanoma skin cancers basal (BCC) and squamous (SCC) cell carcinoma, and the possible influence of MMPs in their differences.

Molecular basis of basal cell carcinoma: analysis of differential gene expression by differential display PCR and expression array

Basal cell carcinoma (BCC) is the most common tumor in the Caucasian population. Although BCC rarely metastasize and cause death, they are problematic due to their destructive growth and the frequent localization on the face. Until now the knowledge of genes differentially expressed in BCC has been incomplete. To elucidate the complex alterations in BCC-associated gene expression, we took advantage of 2 techniques: the differential display RT-PCR (DD-PCR) and the differential hybridization of cDNA arrays. Using DD-PCR, we showed differential expression of genes known from other biological contexts (e.g., rac, ubiquitin hydrolase), which could now be associated with BCC. In addition, we detected unknown genes possibly contributing to the carcinogenesis of BCC. Of the 588 genes screened by differential hybridization of the Atlas human cDNA array, differences in the expression levels of BCC were observed for 10 genes. These data were obtained with RNA probes pooled from several BCC of different donors and were subsequently confirmed by semiquantitative RT-PCR for Janus protein tyrosine kinase 3 (Jak3), microsomal glutathione S-transferase 1 (GST 12), teratocarcinoma-derived growth factor cripto, glutaredoxin and the monocyte chemoattractant protein 1 (MCP-1) in 10 individual BCC specimens, 2 squamous cell carcinoma (SCC), the cell line HaCaT and cultured normal human keratinocytes (NHK) in comparison to normal skin. These genes are candidates from gene families with known association to tumors, but they have not been reported in the carcinogenesis of BCC yet. In summary, both approaches allow the detection of differentially expressed genes possibly involved in the carcinogenesis of BCC.

Localization of a non-melanoma skin cancer susceptibility region within the major histocompatibility complex by association analysis using microsatellite markers

The major histocompatibility complex (MHC) is known to have a role in the development of non-melanoma skin cancer (NMSC), although the genes and mechanisms involved have yet to be determined. To identify the susceptibility locus for NMSC within the MHC, we used a collection of well-defined polymorphic microsatellite markers from the Human leucocyte antigen (HLA) region for an association analysis of 150 cases with NMSC and 200 healthy controls selected from the Busselton population in Western Australia. High-resolution mapping was undertaken using a total of 40 highly polymorphic markers located at regular intervals across the HLA region (3.6Mb). Polymerase chain reaction (PCR) analysis was initially performed on pooled DNA markers to detect those markers that showed different allele profiles. Statistically significant differences in allelic frequencies (differentiating alleles) were found between cases and controls at three polymorphic microsatellite loci within a 470-kb genomic susceptibility region ranging between 6 kb centromeric of the HLA-B gene and intron 5 of the DDR gene. Interestingly, this genome region corresponded completely with the psoriasis-susceptibility locus. The three differentiating alleles and another four markers outside the susceptibility region were then PCR tested by individual genotyping of cases and controls. The newly identified susceptibility locus for NMSC within the MHC was found to be significantly different between the cases and controls by comparisons of allele frequencies at the three differentiating loci estimated from DNA pools and then confirmed by individual genotyping. This is the first study using high density microsatellite markers to localize a NMSC susceptibility region within the human genome.

Incidence and prediction of nonmelanoma skin cancer post-renal transplantation: a prospective study in Queensland, Australia

BACKGROUND

Nonmelanoma skin cancer (NMSC) is a significant clinical problem after renal transplantation, particularly in areas of high UV light exposure. A single-center prospective study of a population of Queensland renal transplant recipients was performed with the aims of: (1) establishing NMSC incidence and tumor accrual post-renal transplantation, and (2) developing a clinically derived predictive index to identify transplant recipients at greatest risk.

METHODS

Three hundred ten of 398 transplant recipients (78%) who underwent baseline assessment between July 1999 and April 2000 were reassessed a mean of 18 +/- 3.5 (SD) months later. A structured interview, full skin examination, biopsy of suspicious lesions, and review of medical and pathological records were used to determine the number and types of NMSC arising between the two assessments. Incidence (percentage of the population developing NMSC per year) and tumor accrual (number of tumors per person per year) were calculated. A clinically derived predictive index was generated using stepwise logistic regression models.

RESULTS

Overall NMSC incidence was 28.1% and increased with duration of immunosuppression therapy: 18.8%, 24.8%, 33.3%, and 47.1% at less than 5, 5 to 10, 10 to 20, and greater than 20 years of immunosuppression therapy, respectively. Mean NMSC accrual was 1.85 +/- 3.84 tumors/person/y, increasing to 3.35 +/- 4.29 tumors/person/y after 20 years of immunosuppression therapy. Renal transplant recipients were stratified into categories of high and low NMSC risk by using predictive indices.

CONCLUSION

Clinically derived predictive indices can allow NMSC risk stratification of an Australian transplant population and may provide an evidence-based and cost-effective approach to developing a targeted clinical NMSC surveillance program.

Spectral UV in public shade settings

The protective nature of specific shade environments was investigated by measuring the spectral UV in the shade for the three planes (horizontal, 45 degrees and vertical) and comparing this to that on a horizontal plane in full sun. Spectral UV irradiance measurements were made under clear sky conditions at a sub-tropical southern hemisphere site. The solar UV in the shade of a shade umbrella, covered verandah, covered sand pit and covered walkway were measured for an increasing solar zenith angle, between March and August, for the times of 11:30 a.m.-12:30 p.m. and 2:30-3:30 p.m. The ultraviolet protection factors provided ranged from 1.4 to 10. This research shows that there is sufficient UV in the shade to cause erythema on the human body in a short period of time. For the shade umbrella placed on dry grass the time able to be spent in the shade in the middle of the day before experiencing mild erythema increased from 35 to 60 min as the solar zenith angle increased from 33 to 52 degrees. Erythemal UV levels in the shade of a northern facing covered verandah, with trees in close proximity, were approximately up to five times less than the erythemal UV beneath the shade umbrella that had no surrounding trees. Shade structures must be given careful consideration when construction occurs. Even though the UV transmission through the materials may be very low, it is the construction of the entire shade setting that determines the exposure beneath the shade structure.

Ultraviolet radiation and autoimmune disease: insights from epidemiological research

This review examines the epidemiological evidence that suggests ultraviolet radiation (UVR) may play a protective role in three autoimmune diseases: multiple sclerosis, insulin-dependent diabetes mellitus and rheumatoid arthritis. To date, most of the information has accumulated from population studies that have studied the relationship between geography or climate and autoimmune disease prevalence. An interesting gradient of increasing prevalence with increasing latitude has been observed for at least two of the three diseases. This is most evident for multiple sclerosis, but a similar gradient has been shown for insulin-dependent diabetes mellitus in Europe and North America. Seasonal influences on both disease incidence and clinical course and, more recently, analytical studies at the individual level have provided further support for a possible protective role for UVR in some of these diseases but the data are not conclusive. Organ-specific autoimmune diseases involve Th1 cell-mediated immune processes. Recent work in photoimmunology has shown ultraviolet B (UVB) can specifically attenuate these processes through several mechanisms which we discuss. In particular, the possible contribution of an UVR-induced increase in serum vitamin D (1,25(OH)2D3) levels in the beneficial immunomodulation of these diseases is discussed.

Progress in cutaneous cancer research

Cutaneous cancers represent a major public health concern due to the very high incidence, associated medical costs, substantial mortality, and cosmetic deformities associated with treatment. Considerable progress in basic research has provided new insights into the underlying genetic basis of the major human cutaneous cancers, malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. In turn, these genetic insights have illuminated biochemical pathways that promise to provide new approaches to the prevention and treatment of cutaneous neoplasms. This review will detail the evolving genetic information and indicate how this information is being used to refine experimental models that serve to both define the biochemistry of cancer pathogenesis and test novel approaches to cancer therapy. Combined with preventive measures to reduce exposure to sunlight, these advances are likely to reduce this major public health burden in the coming decade.

UV-induced skin changes due to regular use of commercial sunbeds

BACKGROUND/AIM

Increased pigmentation and thickening of the epidermis are the most important photoprotective skin reactions induced by ultraviolet (UV) radiation. The present study was designed to find out what changes are induced by regular use of commercial sunbeds twice weekly over a period of 6 weeks.

METHODS

The parameters analysed were skin pigmentation measured by chromametry, minimal erythema dose (MED) as a parameter of light sensitivity, epidermal thickening as determined by histology, induction of keratinocyte apoptosis as determined by TUNEL staining and antioxidant metabolism as measured by changes of cis- and trans-urocanic acid (UCA) content of the skin.

RESULTS

As expected, chromametry confirmed the clinically obvious increased skin pigmentation. However, no increase in MED was observed. In addition, neither epidermal thickening nor sunburn cells were seen. Significant detectable changes in proportion of the UCA isomer content of the UV-exposed skin were seen. The total UCA and cis-UCA content increased significantly between nearly all points of measurement. The amount of trans-UCA first decreased, then increased significantly between the different time points.

CONCLUSION

Our data indicate that sunbed-induced tanning is non-protective, which has to be addressed for persons looking for this effect before planning a stay in a sunny climate. However, sunbed-induced tanning may influence immunological reactions.

Micronucleus evaluation in mitogen-stimulated lymphocytes of PUVA treated patients

PUVA describes the treatment of patients with psoralens plus an exposure to a source of UV light of 320-400 nm (UVA). Contradictory results have been reported on the chromosomal damage of PUVA when assayed by sister chromatid exchange (SCE) method. Micronucleus (MN) test is used to detect both clastogenic (breaking) and aneugenic (abnormal segregation) effect of physical/chemical agents on the chromosomes. No data have been found on the MN formation in the cells of PUVA treated patients. Frequency of micronuclei in 72 hours cultivated/mitogen-stimulated lymphocytes of patients have been evaluated at zero time and after 20, 40, 60 sessions of PUVA treatment. While the beginning MN frequency was approximately 0.22% (n=23), it raised to approximately 0.32 (n=23), approximately 0.42 (n=14) and approximately 0.53% (n=10) corresponding respectively to 20, 40 and 60 sessions. These sessions correspond reciprocally to 54+/-23, 172+/-48, 300+/-61 joules/cm2 of UVA and 13, 26, 39 mg/kg of 8-metoxypsoralen (8-MOP). While large interindividual variances were apparent, highly significant differences have been observed between initial MN frequency and after that of the 20, 40 and 60 sessions, (p = 0.000, p = 0.004, p = 0.005, reciprocally, Wilcoxon two-related samples test). The coefficient of correlation between MN frequency and UVA doses starting from zero to 60 sessions of treatment has been found as r = 0.61. This indicates a significant relationship between UVA doses and MN frequencies. However, MN inducibility and synergistic property of 8-MOP with UVA should be taken into account. Gradual MN increase during different sessions of PUVA treatment shows that--once appeared--a part of MN at least persist in the cells of patients from a few days to a few weeks. Smoking as a confounding factor seems to increase MN frequency (p = 0.053, Mann-Whitney U-test) in the beginning population, taken as the control population. This is the first report on the kinetics of MN formation during different sessions of PUVA treatment. Based on our results, we concluded that PUVA treatment causes a detectable chromosome damaging effect on the relatively profound cells/tissues of its human users. Therapists should be careful with its use, especially on the patients who may be more susceptible to carcinogenesis (e.g. immunosuppressed and/or elderly subjects).

Sunbed use at home: risk behaviour and psychosocial determinants

The objective of this study was to analyse the behaviour of people with regard to sunbed use at home, and to analyse the psychosocial determinants of intention and behaviour with regard to limiting the health risk of using sunbeds at home. Data were collected by means of a telephone survey among 349 adults from the Dutch general public who use sunbeds at home (response=95%). Determinants that were assessed were: attitude with respect to safer use and the use of sunbeds in general, the social influences people encounter to use sunbeds in a safer way, and the self-efficacy expectations people have of their ability to use sunbeds more safely. The results showed that there were great differences between people's perceptions of their safe sunbed behaviour, and their actual safety behaviour. Almost all respondents (94%) thought that their sunbed behaviour was safe, while in reality only 37% of the respondents used the sunbed in accordance with the safety guidelines. The safer users of sunbeds differed on many determinants from the unsafe users. Intention to minimize the health risk when using sunbeds could be predicted by a person's perceived self-efficacy, the overall attitude and anticipated regret beliefs (R2=0.52). Sunbed users should be made aware of their risk behaviour with regard to sunbeds as well as providing information on changing determinants, in order to positively change people's intentions and behaviour with regard to the safer use of sunbeds.