Community perceptions of adequate levels and reasons for skin protection

In this study the authors addressed whether or not community members use relevant risk factors to determine an appropriate level of skin protection behavior in the prevention of skin cancer. The authors conducted a postal survey with a community sample of 3,600 Queensland residents that they randomly selected from the Commonwealth electoral roll. The predictors of perceptions of doing enough skin protection included intrapersonal, social, and attitudinal influences. People protected themselves from the sun primarily out of a desire for future good health and on other occasions did not protect themselves from the sun because they were not out there long enough to get burnt. The predictors of perceptions of doing enough skin protection indicated that participants were aware of relevant risk factors. The main reasons that people protect themselves from the sun suggest that they are acting on many health promotion messages. However, skin cancer prevention programs need to move beyond increasing awareness and knowledge of the disease to providing a supportive environment and enhancing individual skills. Health promotion campaigns could reinforce appropriate risk assessment and shape an individual's decision about how much sun protection is needed.

Community perceptions of suspicious pigmented skin lesions: are they accurate when compared to general practitioners?

Community responses (n = 925, response rate = 71%) of a series of eight photographs of pigmented skin lesions were compared against those of general practitioners (n = 114, response rate = 77%), considered to be the most relevant gold standard. The eight photographs included three melanomas, two potentially malignant lesions and three benign pigmented lesions. Over the pool of lesions examined, the average probability that community members thought a lesion was likely to be skin cancer (0.68 [99% CI = 0.66-0.69]) was higher (p < 0.0001) than that of the comparison general practitioners 0.58 [99% CI = 0.55-0.62]. This reflects a general (but not consistent) inflated propensity to over-diagnose among community members. The average probability that respondents indicated they would seek medical advice for a lesion was 0.71 [99% CI = 0.70-0.73]. As expected, this was strongly associated with their perceptions of the skin lesion. These results suggest that the community can play a valuable role in assessing the need for medical evaluation of pigmented skin lesions. (c) 2004 International Society for Preventive Oncology. Published by Elsevier Ltd. All rights reserved.

A genome scan for epidermal skin pattern in adolescent twins reveals suggestive linkage on 12p13.31

Deterioration in stratum corneum reticular patterning (skin pattern or skin wrinkling) has been associated with increased rates of solar keratoses and skin cancer. A previous analysis of data from the twin sample used in this investigation has shown that 86% of the variation in skin pattern is genetic at age 12 and 62% in an adult sample (mean age 47.5). Variation due to genetic influences is likely to be influenced by more than one locus. Here, we present results of a genome-wide linkage scan of skin pattern in adolescent twins and siblings from 428 nuclear twin families. Sib-pair linkage analysis was performed on skin pattern data collected from twins at age 12 (378 informative families) and 14 (316 families). Suggestive linkage was found at marker D12S397 (12p13.31, logarithm of the odds (lod) 1.94), when the effect of the trait locus was modelled to influence the skin pattern equally at both ages 12 and 14. In the same analysis, a peak was seen at 4q23 with a lod score of 1.55. A possible candidate for the peak at 12p13.31 is the protease inhibitor, alpha-2-macroglobulin.

Clinical outcomes from skin screening clinics within a community-based melanoma screening program

Background : Within a randomized trial of population screening for melanoma, primary care physicians conducted whole-body skin examinations and referred all patients with suspect lesions to their own doctor for further treatment. Objective: Our aim was to describe characteristics of skin screening participants, clinical screening diagnoses, management following referral, and specificity and yield of screening examinations. Methods: Information collected from consent forms, referral forms, and histopathological reports of lesions that had been excised or undergone biopsy was analyzed by means of descriptive statistics. Results: A total of 16,383 whole-body skin examinations resulted in 2302 referrals (14.1% overall; 15.5% men, 18.2% >= 50 years of age) for 4129 suspect lesions (including 222 suspected melanoma, 1101 suspected basal cell carcinomas [BCCs], 265 suspected squamous cell carcinomas [SCCs]). Histopathologic results were available for 94.8% of 1417 lesions excised and confirmed 33 melanomas (23 in men; 24 in participants ? 50 years of age), 259 BCCs, and 97 SCCs. The probability of detecting skin cancer of any type within the program was 2.4%. The estimated specificity of whole-body skin examinations for melanoma was 86.1% (95% confidence interval = 85.6-86.6). The positive predictive value (number of confirmed/number of lesions excised or biopsied x 100) for melanoma was 2.5%, 19.3% for BCC, and 7.2% for SCC (overall positive predictive value for skin cancer, 28.9%). Limitations: Follow-up of participants with a negative screening examination has not been conducted for the present investigation. Conclusions: The rate of skin cancer detected per 100 patients screened was higher than previously reported and men and attendees older than 50 years more frequently received a referral and diagnosis of melanoma. The specificity for detection of melanoma through whole-body skin examination by a primary care physician was comparable to that of other screening tests, including mammography.

Quantitative analysis of MC1R gene expression in human skin cell cultures

To address the issue of melanocortin-1 receptor (MC1R) expression in non-melanocytic cells, we have quantitatively evaluated the relative expression levels of both MC1R mRNA and protein in a subset of different cell types. Using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) at high cycle numbers, we detected MC1R mRNA in all cell types examined, including human embryonic kidney-293 (HEK 293) cells, a cell type widely used as a negative control in melanocortin expression studies. Quantitative real-time PCR revealed the highest levels of MC1R transcripts were in melanocytic cells, whereas the keratinocyte and fibroblast cell cultures examined had only a low level of expression, similar to that of HEK 293 cells. Antibody mediated detection of MC1R protein in membrane extracts demonstrated exogenous receptor in MC1R transfected cell lines, as well as endogenous MC1R in melanoma cells. However, radioligand binding procedures were required to detect MC1R protein of normal human melanocytes and no surface expression of MC1R was detected in any of the non-melanocytic cells examined. This was consistent with their low level of mRNA, and suggests that, if present, the levels of surface receptor are significantly lower than that in melanocytes. The capacity of such limited levels of MC1R protein to influence non-melanocytic skin cell biology would likely be severely compromised. Indeed, the MC1R agonist [NIe(4), D-Phe(7)] alpha-melanocyte stimulating hormone (NDP-MSH) was unable to elevate intracellular cyclic adenosine monophosphate (cAMP) levels in the keratinocyte and fibroblast cells examined, whereas a robust increase was elicited in melanocytes. Although there are a variety of cell types with detectable MC1R mRNA, the expression of physiologically significant levels of the receptor may be more restricted than the current literature indicates, and within epidermal tissue may be limited to the melanocyte

Expression of p53 tumor suppressor protein in sun-exposed skin and associations with sunscreen use and time spent outdoors: A community-based study

The p53 gene is a tumor suppressor gene that is commonly mutated in skin cancer and sun-exposed skin, and this can be detected through immunohistochemical expression of the p53 protein. The authors hypothesized that time spent outdoors is associated with p53 protein expression in human skin and that sunscreen use counteracts the association. In 1996, they investigated this in a community-based cross-sectional study in Australia. Detailed information about skin type, time spent outdoors, and sunscreen use was collected from 139 residents of a subtropical township who also provided a skin biopsy from the back of the hand for measurement of p53 expression. Increasing time spent outdoors was positively associated with immuno reactivity in the whole epidermis and in the basal layer of the epidermis. After adjustment for confounders, p53 immunoreactivity was twice as high for people who used sunscreen 1 or 2 days per week as for those who used sunscreen daily (whole epidermis: ratio estimate = 2.0, 95% confidence interval: 1.1, 3.6; basal layer: ratio estimate = 1.7, 95% confidence interval: 0.9, 3.1). The authors conclude that p53 immunoreactivity in the skin is a marker of exposure to ultraviolet light in the past 6 months, but this may be mitigated by regular application of sunscreen.

Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial

Background The use of sunscreens on the skin can prevent sunburn but whether long-term use can prevent skin cancer is not known. Also, there is evidence that oral betacarotene supplementation lowers skin-cancer rates in animals, but there is limited evidence of its effect in human beings. Methods In a community-based randomised trial with a 2 by 2 factorial design, individuals were assigned to four treatment groups: daily application of a sun protection factor 15-plus sunscreen to the head, neck, arms, and hands, and betacarotene supplementation (30 mg per day); sunscreen plus placebo tablets; betacarotene only; or placebo only. Participants were 1621 residents of Nambour in southeast Queensland, Australia. The endpoints after 4.5 years of follow-up were the incidence of basal-cell and squamous-cell carcinomas both in terms of people treated for newly diagnosed disease and in terms of the numbers of tumours that occurred. Analysis of the effect of sunscreen was based only on skin cancers that developed on sites of daily application. All analyses were by intention to treat. Findings 1383 participants underwent full shin examination by a dermatologist in the follow-up period. 250 of them developed 758 new skin cancers during the follow-up period. There were no significant differences in the incidence of first new shin cancers between groups randomly assigned daily sunscreen and no daily sunscreen (basal-cell carcinoma 2588 vs 2509 per 100 000; rate ratio 1.03 [95% CI 0.73-1.46]; squamous-cell carcinoma 876 vs 996 per 100 000; rate ratio 0.88 [0.50-1.56]). Similarly, there was no significant difference between the betacarotene and placebo groups in incidence of either cancer (basal-cell carcinoma 3954 vs 3806 per 100 000; 1.04 [0.73-1.27]; squamous-cell carcinoma 1508 vs 1146 per 100 000; 1.35 [0.84-2.19]). In terms of the number of tumours, there was no effect on incidence of basal-cell carcinoma by sunscreen use or by betacarotene but the incidence of squamous-cell carcinoma was significantly lower in the sunscreen group than in the no daily sunscreen group (1115 vs 1832 per 100 000; 0.61 [0.46-0.81]). Interpretation There was no harmful effect of daily use of sunscreen in this medium-term study. Cutaneous squamous-cell carcinoma, but not basal-cell carcinoma seems to be amenable to prevention through the routine use of sunscreen by adults for 4.5 years. There was no beneficial or harmful effect on the rates of either type of skin cancer, as a result of betacarotene supplementation.

Anthropometric measures in relation to Basal Cell Carcinoma: a longitudinal study

Background: The relationship between anthropometric indices and risk of basal cell carcinoma ( BCC) is largely unknown. We aimed to examine the association between anthropometric measures and development of BCC and to demonstrate whether adherence to World Health Organisation guidelines for body mass index, waist circumference, and waist/ hip ratio was associated with risk of BCC, independent of sun exposure. Methods: Study participants were participants in a community- based skin cancer prevention trial in Nambour, a town in southeast Queensland ( latitude 26 degrees S). In 1992, height, weight, and waist and hip circumferences were measured for all 1621 participants and weight was remeasured at the end of the trial in 1996. Prevalence proportion ratios were calculated using a log- binomial model to estimate the risk of BCC prior to or prevalent in 1992, while Poisson regression with robust error variances was used to estimate the relative risk of BCC during the follow- up period. Results: At baseline, 94 participants had a current BCC, and 202 had a history of BCC. During the 5- year follow- up period, 179 participants developed one or more new BCCs. We found no significant association between any of the anthropometric measures or indices and risk of BCC after controlling for potential confounding factors including sun exposure. There was a suggestion that short- term weight gain may increase the risk of developing BCC for women only. Conclusion: Adherence to World Health Organisation guidelines for body mass index, waist circumference and waist/ hip ratio is not significantly associated with occurrence of basal cell carcinomas of the skin.

Melanocortin-1 receptor genotype is a risk factor for basal and squamous cell carcinoma

MC1R gene variants have previously been associated with red hair and fair skin color, moreover skin ultraviolet sensitivity and a strong association with melanoma has been demonstrated for three variant alleles that are active in influencing pigmentation: Arg151Cys, Arg160Trp, and Asp294His. This study has confirmed these pigmentary associations with MC1R genotype in a collection of 220 individuals drawn from the Nambour community in Queensland, Australia, 111 of whom were at high risk and 109 at low risk of basal cell squamous cell carcinoma. Comparative allele frequencies for nine MC1R variants that have been reported in the Caucasian population were determined for these two groups, and an association between prevalence of basal cell carcinoma, squamous cell carcinoma, solar keratosis and the same three active MC1R variant alleles was demonstrated [odds ratio=3.15 95% CI (1.7, 5.82)]. Three other commonly occurring variant alleles: Val60Leu, Val92Met, and Arg163Gln were identified as having a minimal impact on pigmentation phenotype as well as basal cell carcinoma and squamous cell carcinoma risk. A significant heterozygote effect was demonstrated where individuals carrying a single MC1R variant allele were more likely to have fair and sun sensitive skin as well as carriage of a solar lesion when compared with those individuals with a consensus MC1R genotype. After adjusting for the effects of pigmentation on the association between MC1R variant alleles and basal cell carcinoma and squamous cell carcinoma risk, the association persisted, confirming that presence of at least one variant allele remains informative in terms of predicting risk for developing a solar-induced skin lesion beyond that information gained through observation of pigmentation phenotype.

Communication and health beliefs - Mass and interpersonal influences on perceptions of risk to self and others

This study investigated the impact of media coverage of a health issue (skin cancer) on judgements of risk to self and others and the role of related communication processes. Consistent with predictions derived from the impersonal impact hypothesis, the effects of mass communication were more evident in perceptions of risk to others rather than in perceptions of personal risk. Perceptions of personal risk were more strongly correlated with interpersonal communication. However, as suggested by media system dependency theory, the relationship between mass communication and beliefs was complex. The impact of mass communication on both personal and impersonal perceptions was bound to be moderated by self-reported dependence on mass mediated information. The effect of this two-way interaction 071 perceptions of personal risk was partially mediated through interpersonal communication. Results point to the interdependence of mass and interpersonal communication as sources of social influence and the role of media dependency in shaping media impact.

Isolation (from a basal cell carcinoma) of a functionally distinct fibroblast-like cell type that overexpresses Ptch

In this study we report on the isolation and characterization of a nonepithelial, nontumorigenic cell type (BCC1) derived from a basal cell carcinoma from a patient. The BCC1 cells share many characteristics with dermal fibroblasts, such as the expression of vimentin, lack of expression of cytokeratins, and insensitivity to agents that cause growth inhibition and differentiation of epithelial cells; however, significant differences between BCC1 cells and fibroblasts also exist. For example, BCC1 cells are stimulated to undergo DNA synthesis in response to interferon-gamma, whereas dermal fibroblasts are not. More over, BCC1 cells overexpress the basal cell carcinoma-specific genes ptch and ptch2 . These data indicate that basal cell carcinomas are associated with a functionally distinct population of fibroblast-like cells that overexpress known tumor-specific markers (ptch and ptch2 ).

Sun exposure and interaction with family history in risk of melanoma, Queensland, Australia

Sun exposure is the main environmental risk factor for melanoma, but the timing of exposure during life that confers increased risk is controversial. Here we provide the first report of the association between lifetime and age-specific cumulative ultraviolet exposure and cutaneous melanoma in Queensland, Australia, an area of high solar radiation, and examine the association separately for families at high, intermediate and low familial melanoma risk. Subjects were a population-based sample of melanoma cases diagnosed and registered in Queensland between 1982 and 1990 and their relatives. The analysis included 1,263 cases and relatives with confirmed cutaneous melanoma and 3,111 first-degree relatives without melanoma as controls. Data an lifetime residence and sun exposure, family history and other melanoma risk factors were collected by a mailed questionnaire. Using conditional multiple logistic regression with stratification by family, cumulative sun exposure in childhood and in adulthood after age 20 was significantly associated with melanoma, with estimated relative risks of 1.15 per 5,000 minimal erythemal doses (MEDs) from age 5 to 12 years, and 1.52 per 5 MEDs/day from age 20. There was no association with sun exposure in families at high familial melanoma risk. History of nonmelanoma skin cancer (relative risk [RR] = 1.26) and multiple sunburns (RR = 1.31) were significant risk factors. These findings indicate that sun exposure in childhood and in adulthood are important determinants of melanoma but not in those rare families with high melanoma susceptibility, in which genetic factors are likely to be more important. (C) 2002 Wiley-Liss, Inc.

A review of animal models for the study of arsenic carcinogenesis

As inorganic arsenic is a proven human carcinogen, significant effort has been made in recent decades in an attempt to understand arsenic carcinogenesis using animal models, including rodents (rats and mice) and larger mammals such as beagles and monkeys. Transgenic animals were also used to test the carcinogenic effect of arsenicals, but until recently all models had failed to mimic satisfactorily the actual mechanism of arsenic carcinogenicity. However, within the past decade successful animal models have been developed using the most common strains of mice or rats. Thus dimethylarsinic acid (DMA), an organic arsenic compound which is the major metabolite of inorganic arsenicals in mammals, has been proven to be tumorigenic in such animals. Reports of successful cancer induction in animals by inorganic arsenic (arsenite and arsenate) have been rare, and most carcinogenetic studies have used organic arsenicals such as DMA combined with other tumor initiators. Although such experiments used high concentrations. of arsenicals for the promotion of tumors, animal models using doses of arsenicals species closed to the exposure level of humans in endemic areas are obviously the most significant. Almost all researchers have used drinking water or food as the pathway for the development of animal model test systems in order to mimic chronic arsenic poisoning in humans; such pathways seem more likely to achieve desirable results. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.