DNA repair, dysplastic nevi, and sunlight sensitivity in the development of cutaneous malignant melanoma

Publication Trends and Hot Topics in Dysplastic Nevus Research: A 30-Year Bibliometric Analysis

INTRODUCTION

Dysplastic nevi are pigmented lesions that exhibit clinical and histological features of both common nevi and melanoma. In recent years, there has been an increase in publications on dysplastic nevi. Bibliometric analysis is a method of evaluating trends in large number of publications and identifying popular topics.

OBJECTIVES

The objective of this study is to provide an overview of the landscape of publications related to dysplastic nevi, visualize trends and identify popular topics in the literature.

METHODS

Thomson Reuters' Web of Science database was searched with the following query in title, abstract or keywords: TS = ("dysplastic nevus" OR "clark nevus" OR "atypical nevus" OR "dysplastic nevi" OR "clark nevi" OR "atypical nevi"). Time span was set to 1992-2022. Document type was set to Article. Titles, authors, abstracts, institutions, countries, journals, references, and the citation information were recorded.

RESULTS

Although the number of publications has declined over time, the USA remains the leading contributor to published articles. Key clusters of frequently used keywords were identified. The Journal of the American Academy of Dermatology had the highest number of published titles. Country and journal analysis were supplemented by co-citation and co-cited reference cluster analysis. Burst analyses revealed authors like Kittler, Argenziano, and Gandini as significant contributors, with their works receiving strong citation bursts extending until the end of the study period.

CONCLUSIONS

This bibliometric analysis revealed trends and interest pockets in the literature pertaining to dysplastic nevi and melanoma. This study aids in understanding the current research landscape and highlights potential future directions in this field.

The role of dual-specificity phosphatase 3 in melanocytic oncogenesis

Dual-specificity phosphatase 3 (DUSP3), also known as Vaccinia H1-related phosphatase, is a protein tyrosine phosphatase that typically performs its major role in the regulation of multiple cellular functions through the dephosphorylation of its diverse and constantly expanding range of substrates. Many of the substrates described so far as well as alterations in the expression or the activity of DUSP3 itself are associated with the development and progression of various types of neoplasms, indicating that DUSP3 may be an important player in oncogenesis and a promising therapeutic target. This review focuses exclusively on DUSP3's contribution to either benign or malignant melanocytic oncogenesis, as many of the established culprit pathways and mechanisms constitute DUSP3's regulatory targets, attempting to synthesize the current knowledge on the matter. The spectrum of the DUSP3 interactions analyzed in this review covers substrates implicated in cellular growth, cell cycle, proliferation, survival, apoptosis, genomic stability/repair, adhesion and migration of tumor melanocytes. Furthermore, the speculations raised, based on the evidence to date, may be considered a fundament for potential research regarding the oncogenesis, evolution, management and therapeutics of melanocytic tumors.

Reduced DNA Repair Capacity in Prostate Cancer Patients: A Phenotypic Approach Using the CometChip

Prostate cancer (PCa) accounts for 22% of the new cases diagnosed in Hispanic men in the US. Among Hispanics, Puerto Rican (PR) men show the highest PCa-specific mortality. Epidemiological studies using functional assays in lymphocytes have demonstrated that having low DRC is a significant risk factor for cancer development. The aim of this study was to evaluate variations in DRC in PR men with PCa. Lymphocytes were isolated from blood samples from PCa cases (n = 41) and controls (n = 14) recruited at a hospital setting. DRC levels through the nucleotide excision repair (NER) pathway were measured with the CometChip using UVC as a NER inductor. The mean DRC for controls and PCa cases were 20.66% (±7.96) and 8.41 (±4.88), respectively (p < 0.001). The relationship between DRC and tumor aggressiveness was also evaluated. Additional comparisons were performed to evaluate the contributions of age, anthropometric measurements, and prostate-specific antigen levels to the DRC. This is the first study to apply the CometChip in a clinical cancer study. Our results represent an innovative step in the development of a blood-based screening test for PCa based on DRC levels. Our data also suggest that DRC levels may have the potential to discriminate between aggressive and indolent cases.

DNA repair phenotype and cancer risk: a systematic review and meta-analysis of 55 case-control studies

DNA repair phenotype can be measured in blood and may be a potential biomarker of cancer risk. We conducted a systematic review and meta-analysis of epidemiological studies of DNA repair phenotype and cancer through March 2021. We used random-effects models to calculate pooled odds ratios (ORs) of cancer risk for those with the lowest DNA repair capacity compared with those with the highest capacity. We included 55 case–control studies that evaluated 12 different cancers using 10 different DNA repair assays. The pooled OR of cancer risk (all cancer types combined) was 2.92 (95% Confidence Interval (CI) 2.49, 3.43) for the lowest DNA repair. Lower DNA repair was associated with all studied cancer types, and pooled ORs (95% CI) ranged from 2.02 (1.43, 2.85) for skin cancer to 7.60 (3.26, 17.72) for liver cancer. All assays, except the homologous recombination repair assay, showed statistically significant associations with cancer. The effect size ranged from 1.90 (1.00, 3.60) for the etoposide-induced double-strand break assay to 5.06 (3.67, 6.99) for the γ-H2AX assay. The consistency and strength of the associations support the use of these phenotypic biomarkers; however large-scale prospective studies will be important for understanding their use related to age and screening initiation.

Ambient UVR and Environmental Arsenic Exposure in Relation to Cutaneous Melanoma in Iowa

Intermittent sun exposure is the major environmental risk factor for cutaneous melanoma (CM). Cumulative sun exposure and other environmental agents, such as environmental arsenic exposure, have not shown consistent associations. Ambient ultraviolet radiation (UVR) was used to measure individual total sun exposure as this is thought to be less prone to misclassification and recall bias. Data were analyzed from 1096 CM cases and 1033 controls in the Iowa Study of Skin Cancer and Its Causes, a population-based, case-control study. Self-reported residential histories were linked to satellite-derived ambient UVR, spatially derived environmental soil arsenic concentration, and drinking water arsenic concentrations. In men and women, ambient UVR during childhood and adolescence was not associated with CM but was positively associated during adulthood. Lifetime ambient UVR was positively associated with CM in men (OR for highest vs. lowest quartile: 6.09, 95% confidence interval (CI) 2.21–16.8), but this association was not as strong among women (OR for highest vs. lowest quartile: 2.15, 95% CI 0.84–5.54). No association was detected for environmental soil or drinking water arsenic concentrations and CM. Our findings suggest that lifetime and adulthood sun exposures may be important risk factors for CM.

Cutaneous Melanoma Classification: The Importance of High-Throughput Genomic Technologies

Cutaneous melanoma is an aggressive tumor responsible for 90% of mortality related to skin cancer. In the recent years, the discovery of driving mutations in melanoma has led to better treatment approaches. The last decade has seen a genomic revolution in the field of cancer. Such genomic revolution has led to the production of an unprecedented mole of data. High-throughput genomic technologies have facilitated the genomic, transcriptomic and epigenomic profiling of several cancers, including melanoma. Nevertheless, there are a number of newer genomic technologies that have not yet been employed in large studies. In this article we describe the current classification of cutaneous melanoma, we review the current knowledge of the main genetic alterations of cutaneous melanoma and their related impact on targeted therapies, and we describe the most recent high-throughput genomic technologies, highlighting their advantages and disadvantages. We hope that the current review will also help scientists to identify the most suitable technology to address melanoma-related relevant questions. The translation of this knowledge and all actual advancements into the clinical practice will be helpful in better defining the different molecular subsets of melanoma patients and provide new tools to address relevant questions on disease management. Genomic technologies might indeed allow to better predict the biological - and, subsequently, clinical - behavior for each subset of melanoma patients as well as to even identify all molecular changes in tumor cell populations during disease evolution toward a real achievement of a personalized medicine.

From Bioinspired Glue to Medicine: Polydopamine as a Biomedical Material

Biological structures have emerged through millennia of evolution, and nature has fine-tuned the material properties in order to optimise the structure-function relationship. Following this paradigm, polydopamine (PDA), which was found to be crucial for the adhesion of mussels to wet surfaces, was hence initially introduced as a coating substance to increase the chemical reactivity and surface adhesion properties. Structurally, polydopamine is very similar to melanin, which is a pigment of human skin responsible for the protection of underlying skin layers by efficiently absorbing light with potentially harmful wavelengths. Recent findings have shown the subsequent release of the energy (in the form of heat) upon light excitation, presenting it as an ideal candidate for photothermal applications. Thus, polydopamine can both be used to (i) coat nanoparticle surfaces and to (ii) form capsules and ultra-small (nano)particles/nanocomposites while retaining bulk characteristics (i.e., biocompatibility, stability under UV irradiation, heat conversion, and activity during photoacoustic imaging). Due to the aforementioned properties, polydopamine-based materials have since been tested in adhesive and in energy-related as well as in a range of medical applications such as for tumour ablation, imaging, and drug delivery. In this review, we focus upon how different forms of the material can be synthesised and the use of polydopamine in biological and biomedical applications.

Altered Expression of the Dna Mismatch Repair Proteins Hmlh1 and Hmsh2 in Cutaneous Dysplastic Nevi and Malignant Melanoma

Molecular alterations in the mismatch repair system suggest that this mechanism may be important in the evolution of cutaneous melanoma. Our current study evaluated the expression of two mismatch repair proteins, hMLH1 and hMSH2, in dysplastic nevi (DN) and cutaneous melanoma (CM). Immunohistochemical staining of these proteins was performed on 55 CM and 30 DN specimens. The staining results were divided into three groups: negative, partially positive and strongly positive. Normal adjacent skin cells served as an internal control for positive immunostaining. Altered immunoreactivity of one of the proteins was found in four (13.4%) DN and seven (12.7%) CM. Lack of staining for hMLH1 was observed in two (6.7%) cases of DN and five (9.1%) cases of CM; staining for hMSH2 was absent in two (6.7%) of the DN and two (3.6%) of the CM specimens. Partially positive staining was found in 33.3% and 53.3% for hMLH1 and hMSH2, respectively, in DN, and in 54.5% and 69.1%, respectively, in CMM. Our study shows that complete or partial loss of MMR protein expression occurs in a subset of both DN and CM and may represent a distinct pathway in the development of some DN and CM.

P, Tarantini L, Calista D, Cavalleri T, Angelici L, Consonni D, Pier A. B, Angela C. P, Maria T. L, Bollati V. Blood DNA methylation, nevi number, and the risk of melanoma

Germline mutations determining increased cutaneous malignant melanoma (CMM) risk have been identified in familial and sporadic CMM cases, but they account only for a small proportion of CMM cases. Recent evidence suggests that germline epimutations (e.g. DNA methylation alterations), which can be inherited similarly to genomic mutations and can be detected in normal body cells (including blood), might increase susceptibility to cancer. The aim of the study was to identify germline epimutations of genes that were found to be mutated in familial CMM (p16, p14, CDK4, MC1R, hTERT), immune and inflammatory genes (ICAM-1, TNFα), DNA mismatch repair gene (MLH1), and repetitive elements (ALU, LINE-1, HERV-w). We measured DNA methylation using bisulfite pyrosequencing in peripheral blood mononuclear cells from 167 CMM cases and 164 sex-matched and age-matched controls. We used multivariable logistic regression models to evaluate the association between methylation levels and CMM status or presence of dysplastic nevi. We found an association between the risk of CMM and peripheral blood mononuclear cell methylation levels of TNFα [odds ratio (OR)=1.11, 95% confidence interval (CI)=1.03-1.18], CDK4 (OR=0.76, 95% CI=0.64-0.91), and MLH1 (OR=1.12, 95% CI=1.02-1.22). In control participants, the risk of developing dysplastic nevi was associated with methylation levels of TNFα (OR=0.81, 95% CI=0.69-0.95), hTERT (OR=0.90, 95% CI=0.82-0.99), and ALU (OR=1.56, 95% CI=1.02-2.39). Epimutations in CMM susceptibility genes and in genes involved in response to oxidative damage are associated with the risk of developing CMM or dysplastic nevi. Further studies measuring methylation levels of these genes in prospectively collected samples are warranted to further elucidate their role in the development and progression of CMM.

A majority of human melanoma cell lines exhibits an S phase-specific defect in excision of UV-induced DNA photoproducts

It is well established that efficient removal of highly-promutagenic UV-induced dipyrimidine photoproducts via nucleotide excision repair (NER) is required for protection against sunlight-associated malignant melanoma. Nonetheless, the extent to which reduced NER capacity might contribute to individual melanoma susceptibility in the general population remains unclear. Here we show that among a panel of 14 human melanoma strains, 11 exhibit significant inhibition of DNA photoproduct removal during S phase relative to G0/G1 or G2/M. Evidence is presented that this cell cycle-specific NER defect correlates with enhanced apoptosis and reduced clonogenic survival following UV irradiation. In addition, melanoma strains deficient in S phase-specific DNA photoproduct removal manifest significantly lower levels of phosphorylated histone H2AX at 1 h post-UV, suggesting diminished activation of ataxia telangiectasia and Rad 3-related (ATR) kinase, i.e., a primary orchestrator of the cellular response to UV-induced DNA replication stress. Consistently, in the case of DNA photoproduct excision-proficient melanoma cells, siRNA-mediated depletion of ATR (but not of its immediate downstream effector kinase Chk1) engenders deficient NER specifically during S. On the other hand simultaneous siRNA-mediated depletion of ataxia telangiectasia mutated kinase (ATM) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) exerts no significant effect on either phosphorylation of H2AX at 1 h post-UV or the efficiency of DNA photoproduct removal. Our data suggest that defective NER exclusively during S phase, possibly associated with decreased ATR signaling, may constitute an heretofore unrecognized determinant in melanoma pathogenesis.

An essential role for platelet-activating factor in activating mast cell migration following ultraviolet irradiation

The UVB (290-320 nm) radiation in sunlight is responsible for inducing skin cancer. Exposure to UV radiation is also immunosuppressive, and the systemic immune suppression induced by UV is a well-recognized risk factor for cancer induction. As UVB radiation is absorbed within the upper layers of the skin, indirect mechanisms must play a role in activating systemic immune suppression. One prominent example is mast cell migration, which from the skin to the draining LN is an essential step in the cascade of events leading to immune suppression. What triggers mast cell migration is not entirely clear. Here, we tested the hypothesis that PAF, a lipid mediator of inflammation produced by the skin in response to UV exposure, is involved. Mast cell-deficient mice (Kit(W-sh/W-sh)) are resistant to the suppressive effect of UV radiation, and reconstituting mast cell-deficient mice with normal bone marrow-derived mast cells restores susceptibility to immunosuppression. However, when mast cells from PAFR-/- mice were used, the reconstituted mice were not susceptible to the suppressive effects of UV. Furthermore, PAFR-/- mice showed impaired UV-induced mast cell migration when compared with WT mice. Finally, injecting PAF into WT mice mimicked the effect of UV irradiation and induced mast cell migration but not in PAFR-/- mice. Our findings indicate that PAFR binding induces mast cells to migrate from the skin to the LNs, where they mediate immune suppression.

Increasing melanoma-too many skin cell damages or too few repairs?

Skin melanoma rates have been increasing for a long time in many Western countries. The object of this study was to apply modern problem-solving theory normally used to clear industrial problems to search for roots and causes of this medical question. Increasing cancer rates can be due to too many cell damage incidents or to too few repairs. So far, it has been assumed that the melanoma epidemic mainly is caused by increasing sun tanning habits. In order to explore this problem in more detail, we used cancer statistics from several countries over time and space. Detailed analysis of data obtained and a model study to evaluate the effects from increased damages or decreased repairs clearly indicate that the main reason behind the melanoma problem is a disturbed immune system. The possibility to introduce efficient corrective actions is apparent.

The association of DNA Repair with breast cancer risk in women. A comparative observational study

Background

Previous studies have found a link between a low DNA repair capacity (DRC) level and increased cancer risk. Our aim was to assess the statistical association of DRC level and breast cancer (BC) using a case–control epidemiological study in a Hispanic community.

Methods

We conducted a comparative observational study to assess the validity of DRC in detecting BC in 824 women throughout Puerto Rico. Over a 6-year period, we compared 285 women newly diagnosed with BC to 539 without BC. DRC levels were measured in lymphocytes by means of a host-cell reactivation assay. We assessed the sensitivity, specificity, and association using the receiver operating characteristic curve analysis. Multiple logistic regression-adjusted odds ratios were estimated with 95% confidence level to measure the strength of the association of DRC and BC after adjusting for all confounders simultaneously.

Results

Compared to women without cancer, women with BC showed an average decrease of 60% in their DRC levels (p < 0.001). Validity of the association of DRC as a measure of BC risk showed a sensitivity of 83.2% and specificity of 77.6% (p < 0.0001).

Conclusions

Our results support the usefulness of DRC level as a measure of BC risk. Additional studies in other populations are needed to further verify its usefulness.

Parkinson disease and malignant melanoma in first-degree relatives of patients with early-onset melanoma

BACKGROUND

In a recent study, the link between Parkinson disease and malignant melanoma in patients was also observed in nuclear families, suggesting a possible genetic link between the 2 diseases.

METHODS

To clarify the strength of the association, we used the nationwide Danish cancer and population registers to identify 8567 parents and 7310 siblings of patients in whom malignant melanoma was diagnosed at age 50 years or less. Hospital register data were used to follow relatives for a primary diagnosis of Parkinson disease between 1977 and 2008, and to calculate hospitalization rates for Parkinson disease in the general Danish population for comparison. Similarly, cancer registry data were used to trace cases of malignant melanoma.

RESULTS

The hospitalization rate ratio for Parkinson disease among the melanoma cohort was slightly increased (ratio of observed to expected hospitalizations = 1.2 [95% confidence interval = 0.9-1.5]) on the basis of 54 observed cases. In contrast, the risk among relatives for malignant melanoma was markedly increased. There was no overlap between families affected by multiple cases of Parkinson disease and those affected by multiple cases of malignant melanoma.

CONCLUSIONS

For the age range investigated, our data do not support a genetic link between Parkinson disease and malignant melanoma.

Cutaneous melanoma in Latin America: a population-based descriptive study

Cutaneous melanoma incidences vary between geographic regions and are a health concern for Caucasians and for all ethnic populations. In Latin America, data from population-based cancer registries of cutaneous melanoma incidence rates have rarely been reported. We searched the Cancer Incidence in Five Continents volume IX (CI5-IX) database for cutaneous melanoma and select cases by topography (C43) from 11 population-based cancer registries in Latin America. Between 1998 and 2002, a total of 4,465 cutaneous melanoma cases were reported in Latin America. The average age-standardized incidence rates (per 100,000 persons-year) was 4.6 (male) and 4.3 (female). This study presents an overview of cutaneous melanoma incidence in Latin America, highlighting the need to enhance coverage of population-based cancer registries in Latin America, to allow for a better understanding of this neoplasm in the region. Thus it can help in implementing primary prevention programs for the whole Latino population. At this point in time, early detection messages should target young women and older men in Latin America.

Assays to determine DNA repair ability

DNA repair is crucial to the integrity of the human genome since mammalian cells are continuously exposed to different chemical and physical genotoxic agents. To counteract the lesions induced by these agents, organisms have developed a number of highly conserved repair mechanisms involving numerous protein complexes grouped in several different repair pathways. The importance of studying the individual capacity to repair DNA damage lies in the observation that deficient repair mechanisms of the genome have been linked to the presence of large number of diseases and cancer, and alterations in these mechanisms may also alter the susceptibility of individuals exposed to a particular mutagen. This review focused on the current knowledge of different assays developed to evaluate DNA repair capacity (DRC). These assays, which are grouped into five major categories, have been successfully applied in (1) in vitro studies, (2) epidemiological studies in patients with cancer or other different pathologies, and (3) environmentally or occupationally exposed populations. Nevertheless, some of the limitations include high interlaboratory variability and difficulty to implement the assays on a large scale. The selection of an adequate DRC assay needs to be made on the basis of the objective raised for its application and taking into account a number of determining factors, namely, (1) speed and cost, (2) type of DNA repair to be evaluated, and (3) sample availability.

Dysplastic naevi: an update

Dysplastic naevi are clinically atypical and histologically are characterized by architectural disorder and cytological atypia. Their diagnosis is reproducible if criteria and thresholds are agreed upon. They are significant only in relation to melanoma, as simulants of melanoma, as markers of individuals at increased risk of developing melanoma, and as potential and occasional actual precursors of melanoma. Morphologically and biologically, they are intermediate between common naevi and melanoma. Individuals with dysplastic naevi may have deficient DNA repair, and dysplastic naevi lesions are associated with overexpression of pheomelanin, which may lead to increased oxidative damage and increased potential for DNA damage and tumour progression.

Oncogenic BRAF-positive dysplastic nevi and the tumor suppressor IGFBP7--challenging the concept of dysplastic nevi as precursor lesions?

Oncogenic BRAF as an early and fundamental feature of melanocytic neoplasia has been confirmed with its identification in both melanoma and nevi. Oncogenic BRAF has been shown to induce senescence/apoptosis by up-regulating the tumor suppressor IGFBP7, which acts through autocrine/paracrine pathways to inhibit BRAF-MEK-ERK signaling. Given the putative neoplastic potential of dysplastic nevi, our aim was to ascertain in dysplastic nevi from intermittently sun-exposed skin and of varying severity the frequency of oncogenic BRAF and NRAS and to assess expression of IGFBP7 in the same. BRAF and NRAS genotyping was performed on genomic DNA (isolated using laser capture microdissection) from dysplastic nevi ranging in severity from mild (12), to moderate (11), and to severe (11). Immunohistochemical staining for IGFBP7 was performed on all. Overall, 9 (26%) of 34 cases (2 severely atypical dysplastic nevi, 2 moderately atypical dysplastic nevi, and 5 mildly atypical dysplastic nevi) exhibited the BRAFV600E mutation (P = .22), with lack of IGFBP7 expression in 4 (44.4%) of 9 cases (1 severely atypical, 1 moderately atypical, and 2 mildly atypical); and 25 (73.5%) of 34 cases (9 severely atypical, 9 moderately atypical, and 7 mildly atypical) were BRAFWT, with enhanced IGFBP7 expression in 12 (48%) of 25 cases (6 severely atypical, 3 moderately atypical, and 3 mildly atypical). All cases were NRASWT. The disparate expression of IGFBP7 in BRAFV600E-positive dysplastic nevi (enhanced in 56% and diminished/absent in 44%) indicates that the behavior of oncogenic BRAF in dysplastic nevi, unlike that in malignant melanoma, does not appear to consistently induce senescence/apoptosis through pathways mediated by IGFBP7.

Stepping up melanocytes to the challenge of UV exposure

Exposure to solar ultraviolet radiation (UV) is the main etiological factor for skin cancer, including melanoma. Cutaneous pigmentation, particularly eumelanin, afforded by melanocytes is the main photoprotective mechanism, as it prevents UV-induced DNA damage in the epidermis. Therefore, maintaining genomic stability of melanocytes is crucial for prevention of melanoma, as well as keratinocyte-derived basal and squamous cell carcinoma. A critical independent factor for preventing melanoma is DNA repair capacity. The response of melanocytes to UV is mediated mainly by a network of paracrine factors that not only activate melanogenesis, but also DNA repair, anti-oxidant, and survival pathways that are pivotal for maintenance of genomic stability and prevention of malignant transformation or apoptosis. However, little is known about the stress response of melanocytes to UV and the regulation of DNA repair pathways in melanocytes. Unraveling these mechanisms might lead to strategies to prevent melanoma, as well as non-melanoma skin cancer.

Reduced DNA repair capacity for removing tobacco carcinogen-induced DNA adducts contributes to risk of head and neck cancer but not tumor characteristics

PURPOSE

Although cigarette smoking and alcohol use are known risk factors for squamous cell carcinoma of head and neck (SCCHN), only a few exposed individuals develop this disease, suggesting an individual susceptibility. In this study, we investigated the associations between genetically determined DNA repair capacity (DRC) for removing tobacco-induced DNA adducts and risk of SCCHN and tumor characteristics.

EXPERIMENTAL DESIGN

We measured DRC in cultured T lymphocytes using the host-cell reactivation assay in a hospital-based case-control study of 744 SCCHN patients and 753 age-, sex-, and ethnicity-matched cancer-free controls recruited from The University of Texas M.D. Anderson Cancer Center.

RESULTS

Patients with SCCHN had significantly lower mean DRC (8.84% +/- 2.68%) than controls (9.97% +/- 2.61%; P < 0.0001), and the difference accounted for approximately 2-fold increased risk of SCCHN [adjusted odds ratio (OR), 1.91; 95% confidence interval (CI), 1.52-2.40] after adjustment for other covariates. Compared with the highest DRC quartile of controls, this increased risk was dose dependent (second highest quartile: OR, 1.40; 95% CI, 0.99-1.98; third quartile: OR, 1.87; 95% CI, 1.34-2.62; and fourth quartile: OR, 2.76; 95% CI, 1.98-3.84, respectively; P(trend) < 0.0001). We also assessed the performance of DRC in risk prediction models by calculating the area of under the receiver operating characteristic curve. The addition of DRC to the model significantly improved the sensitivity of the expanded model. However, we did not find the association between DRC and tumor sites and stages.

CONCLUSION

DRC is an independent susceptibility biomarker for SCCHN risk but not a tumor marker.

Genetic susceptibility to distinct bladder cancer subphenotypes

BACKGROUND

Clinical, pathologic, and molecular evidence indicate that bladder cancer is heterogeneous with pathologic/molecular features that define distinct subphenotypes with different prognoses. It is conceivable that specific patterns of genetic susceptibility are associated with particular subphenotypes.

OBJECTIVE

To examine evidence for the contribution of germline genetic variation to bladder cancer heterogeneity.

DESIGN, SETTING, AND PARTICIPANTS

The Spanish Bladder Cancer/EPICURO Study is a case-control study based in 18 hospitals located in five areas in Spain. Cases were patients with a newly diagnosed, histologically confirmed, urothelial cell carcinoma of the bladder from 1998 to 2001. Case diagnoses were reviewed and uniformly classified by pathologists following the World Health Organisation/International Society of Urological Pathology 1999 criteria. Controls were hospital-matched patients (n=1149).

MEASUREMENTS

A total of 1526 candidate variants in 423 candidate genes were analysed. Three distinct subphenotypes were defined according to stage and grade: low-grade nonmuscle invasive (n=586), high-grade nonmuscle invasive (n=219), and muscle invasive (n=246). The association between each variant and subphenotype was assessed by polytomous risk models adjusting for potential confounders. Heterogeneity in genetic susceptibility among subphenotypes was also tested.

RESULTS AND LIMITATIONS

Two established bladder cancer susceptibility genotypes, NAT2 slow-acetylation and GSTM1-null, exhibited similar associations among the subphenotypes, as did VEGF-rs25648, which was previously identified in our study. Other variants conferred risks for specific tumour subphenotypes such as PMS2-rs6463524 and CD4-rs3213427 (respective heterogeneity p values of 0.006 and 0.004), which were associated with muscle-invasive tumours (per-allele odds ratios [95% confidence interval] of 0.56 [0.41-0.77] and 0.71 [0.57-0.88], respectively) but not with non-muscle-invasive tumours. Heterogeneity p values were not robust in multiple testing according to their false-discovery rate.

CONCLUSIONS

These exploratory analyses suggest that genetic susceptibility loci might be related to the molecular/pathologic diversity of bladder cancer. Validation through large-scale replication studies and the study of additional genes and single nucleotide polymorphisms are required.

Short- and long-term effects of UV radiation on the pigmentation of human skin

The incidence of skin cancer, including cutaneous melanoma, has risen substantially in recent years, and epidemiological and laboratory studies show that UV radiation is a major causative factor of this increase. UV damage also underlies photoaging of the skin, and these deleterious effects of UV can be, in part, prevented in skin with higher levels of constitutive pigmentation. We review the clinical studies we have made in recent years regarding the rapid and the long-term responses of the pigmentary system in human skin to UV exposure.Journal of Investigative Dermatology Symposium Proceedings (2009) 14, 32-35; doi:10.1038/jidsymp.2009.10.

UV damage and DNA repair in malignant melanoma and nonmelanoma skin cancer

Exposition of the skin with solar ultraviolet radiation (UV) is the main cause of skin cancer development. The consistently increasing incidences of melanocytic and nonmelanocytic skin tumors are believed to be at least in part associated with recreational sun exposure. Epidemiological data indicate that excessive or cumulative sunlight exposition takes place years and decades before the resulting malignancies arise. The most important defense mechanisms that protect human skin against UV radiation involve melanin synthesis and active repair mechanisms. DNA is the major target of direct or indirect UV-induced cellular damage. Low pigmentation capacity in white Caucasians and rare congenital defects in DNA repair are mainly responsible for protection failures. The important function of nucleotide excision DNA repair (NER) to protect against skin cancer becomes obvious by the rare genetic disease xeroderma pigmentosum, in which diverse NER genes are mutated. In animal models, it has been demonstrated that UVB is more effective to induce skin cancer than UVA. UV-induced DNA photoproducts are able to cause specific mutations (UV-signature) in susceptible genes for squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). In SCC development, UV-signature mutations in the p513 tumor suppressor gene are the most common event, as precancerous lesions reveal approximately 80% and SCCs > 90% UV-specific p53 mutations. Mutations in Hedgehog pathway related genes, especially PTCH1, are well known to represent the most significant pathogenic event in BCC. However, specific UV-induced mutations can be found only in approximately 50% of sporadic BCCs. Thus, cumulative UVB radiation can not be considered to be the single etiologic risk factor for BCC development. During the last decades, experimental animal models, including genetically engineered mice, the Xiphophorus hybrid fish, the south american oppossum and human skin xenografts, have further elucidated the important role of the DNA repair system in the multi-step process of UV-induced melanomagenesis. An increasing body of evidence now indicates that nucleotide excision repair is not the only DNA repair pathway that is involved in UV-induced tumorigenesis of melanoma and nonmelanoma skin cancer. An interesting new perspective in DNA damage and repair research lies in the participation of mammalian mismatch repair (MMR) in UV damage correction. As MMR enzyme hMSH2 displays a p53 target gene, is induced by UVB radiation and is involved in NER pathways, studies have now been initiated to elucidate the physiological and pathophysiological role of MMR in malignant melanoma and nonmelanoma skin cancer development.

Etiology of familial aggregation in melanoma and squamous cell carcinoma of the skin

BACKGROUND

Melanoma and squamous cell carcinoma of the skin (SCC) have been previously shown to coaggregate in families. To shed light on the etiology, we estimated the relative contributions of genetic and environmental factors on the occurrence of each disease, in addition to their influence on coaggregation of the two diseases. Because the malignancies are dependent on UV radiation, we did separate analyses for sun-covered and sun-exposed sites.

METHODS

Our Swedish population-based data included 11 million individuals in 3 million families. We used an extended generalized linear mixed model to estimate the genetic and environmental contribution.

RESULTS

In melanoma, the genetic contribution was 18% [95% confidence interval (95% CI), 13-22%] in the all-sites analysis, whereas the family-shared contribution was slightly higher in the sun-covered compared with sun-exposed sites analysis. SCC revealed very similar estimates in all analyses for both the genetic effects estimated to 8% (95% CI, 4-12%) and family-shared environmental factors at 18% (95% CI, 16-19%), respectively. In the coaggregation analysis, genetic and family-shared environmental components were estimated at 47% (95% CI, 43-51%) and 36% (95% CI, 33-39%), respectively.

CONCLUSIONS

Genetic factors are important in familial aggregation of melanoma and the higher sun-covered compared with sun-exposed site estimate of family-shared environment may convey benefit from cautious sunbathing. In SCC, we observed the highest contribution of family-shared environmental effects in cancer to date, implicating the importance of familial habits. Moreover, we elucidate the potential involvement of genetic variability in the familial coaggregation of melanoma and SCC.

A modified host-cell reactivation assay to measure repair of alkylating DNA damage for assessing risk of lung adenocarcinoma

The nicotine-derived nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces lung adenocarcinoma through formation of DNA adducts. Our previous research on susceptibility to tobacco-induced carcinogenesis focused on benzo[a]pyrene diol epoxide (BPDE) as the in vitro mutagen for phenotype measurements of DNA repair capacity (DRC) in mammalian cells. Here, we present a modified host-cell reactivation (HCR) assay to measure lymphocytic DRC for alkylating DNA damage as is induced by the tobacco-specific nitrosamine, NNK. We substituted dimethyl sulfate (DMS) to create alkylating damage in pCMVluc plasmid DNA and established the damage-repair dose-response curves in both normal and nucleotide excision repair-deficient lymphoblastoid cell lines and in phytohemagglutinin (PHA)-stimulated primary lymphocytes. We then successfully measured the DRC in PHA-stimulated lymphocytes from 48 patients with lung adenocarcinoma and 45 cancer-free controls and tested our hypothesis that lower DRC for alkylating damage is associated with an increased risk of lung adenocarcinoma. The cases exhibited a lower mean DRC than did the controls. A >3-fold increased risk (odds ratio = 3.21; 95% confidence interval = 1.25-8.21) was found for those with DRC levels below the control median. There was no correlation between the DRC measured with this DMS-HCR assay and that from the parallel BPDE-HCR assay. Interestingly, risk increased to >10-fold for those with sub-optimal DRC measured by both DMS- and BPDE-HCR assays. We conclude that variability in DRC is a risk factor for lung cancer and our results provide proof of principle for a new assay that can assess DRC for NNK-induced DNA damage.

Precursors to melanoma and their mimics: nevi of special sites

Melanocytic nevi, which are benign tumors of melanocytes, may have occasional cosmetic significance but, for the most part, they are important only in relation to melanoma. Nevi are the most important simulants of melanoma, both clinically and histologically, and can usually be reliably distinguished from melanomas using published criteria. Some lesions are characterized by greater degrees of atypia and may be more difficult to diagnose. Dysplastic nevi are among the most important simulants of melanoma. Nevi may also be important as potential precursors of melanoma; however, most nevi are stable and will not progress to malignancy. Nevi are vastly more common than melanomas and the rate of progression of individual lesions is very low. Therefore, nevi are not as a rule managed by wholesale excision to prevent melanoma. Nevi are also important as risk markers, identifying individuals at greater risk of developing melanoma in the future. Dysplastic nevi and, to a lesser extent, common acquired and congenital nevi are among the most important melanoma risk markers. Nevi of special sites have been identified as nevi that may show atypical features suggestive of a dysplastic nevus or of a melanoma. However, they are not risk markers and they are not malignancies. Nevi of genital skin, acral skin, and flexural skin are among the most important 'nevi of special sites'. It is important, in considering the differential diagnosis of a lesion in a special site, to avoid overcalling such a lesion as a melanoma or a dysplastic nevus because this could lead to excessive treatment. Conversely, it is important to avoid undercalling a lesion that is a dysplastic nevus or a melanoma as a nevus of special sites, because in this circumstance a patient could lose the opportunity either for surveillance to recognize a developing melanoma at an early, curable stage, or for definitive treatment of an established malignancy. In this monograph, dysplastic nevi and nevi of special sites are compared and contrasted in relation to melanoma.

Ultraviolet B sensitivity of peripheral lymphocytes as an independent risk factor for cutaneous melanoma

Susceptibility to solar ultraviolet is an important melanoma risk factor. We investigated the relationship between individual susceptibility to ultraviolet and risk of melanoma by measuring the apoptosis triggered in peripheral lymphocytes by a low-dose ultraviolet B irradiation (50 J/m(2)) in young and older melanoma patients and controls. Melanoma patients below the age of 40 are more sensitive to UVB-induced apoptosis than older melanoma patients and healthy controls. Analysis of data (adjusted for age and phototype) shows that UVB-induced apoptosis is an important risk factor for melanoma (OR 9.1, 95% CI [3-28], P=0.0001). UVB-induced apoptosis is independent of phototype (P=0.11, Wald test) and tumour thickness (P=0.88, Spearman correlation, for all cases and 0.26 for patients younger than 40 years), and may be used as a functional laboratory test for studying the genetic-environment interactions involved in melanoma occurrence.

In Vitro Sensitivity to Ultraviolet B Light and Skin Cancer Risk: A Case–Control Analysis

BACKGROUND

Mutagen sensitivity, measured as mutagen-induced chromatid breaks per cell in primary lymphocytes in vitro, has been used to study susceptibility to various epithelial cancers. Patients with xeroderma pigmentosum are highly sensitive to ultraviolet (UV) light due to inherited defects in DNA repair and have a 1000-fold higher risk of UV-induced skin cancer than the general population. However, an association between UV-induced chromosomal aberrations and risk of skin cancer in the general population has not been established.

METHODS

We assessed in vitro UVB-induced chromatid breaks in a hospital-based case-control study. The study included 469 patients with skin cancer (231 with nonmelanoma skin cancer [NMSC] and 238 with cutaneous malignant melanoma [CMM]) and 329 cancer-free control subjects. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

Compared with the frequency of UVB-induced chromatid breaks per cell in control subjects (mean = 0.28 breaks per cell, 95% CI = 0.27 to 0.30), that in NMSC patients (basal cell carcinoma [BCC], n = 143, mean = 0.36 breaks per cell, 95% CI = 0.33 to 0.39 and squamous cell carcinoma [SCC], n = 88, mean = 0.35 breaks per cell, 95% CI = 0.32 to 0.38) was higher (P = .001 and P < .001, respectively), but that in CMM case patients (mean = 0.30 breaks per cell, 95% CI = 0.28 to 0.33) was not (P = .22). A frequency of chromatid breaks per cell above the median of control subjects was associated with nearly threefold increased risks for BCC (OR = 2.78, 95% CI = 1.79 to 4.30) and SCC (OR = 2.62, 95% CI = 1.50 to 4.60), but not with an increased risk of CMM. A dose-response relationship was evident between mutagen sensitivity and risk for both BCC (Ptrend < .001) and SCC (Ptrend < .001). Multiplicative interactions between mutagen sensitivity and sun exposure variables on risk, particularly for sunburn in BCC and hair color, tanning ability, and family history of skin cancer in SCC, were seen for NMSC but not CMM.

CONCLUSIONS

UVB-induced mutagen sensitivity may play a role in susceptibility to NMSC but not to CMM.

Polymorphisms in nucleotide excision repair genes and risk of multiple primary melanoma: the Genes Environment and Melanoma Study

Polymorphisms in six genes involved in nucleotide excision repair of DNA were examined in a large population-based case-control study of melanoma. Genotyping was conducted for 2485 patients with a single primary melanoma (controls) and 1238 patients with second or higher order primary melanomas (cases). Patients were ascertained from nine geographic regions in Australia, Canada, Italy and the United States. Positive associations were observed for XPD 312 Asn/Asn versus Asp/Asp [odds ratio (OR) = 1.5, 95% confidence interval (CI) 1.2-1.9] and XPD 751 Gln/Gln versus Lys/Lys (OR = 1.4, 95% CI 1.1-1.7) genotypes and melanoma. The combined XPD Asn (A) 312 + Gln (C) 751 haplotype was significantly more frequent in cases (32%) compared with controls (29%) (P = 0.003) and risk of melanoma increased significantly with one and two copies of the haplotype (ORs 1.2, 95% CI 1.0-1.4, and 1.6, 95% CI 1.2-2.0, trend P = 0.002). No significant associations were observed for HR23B codon 249, XPG codon 1104, XPC codon 939, XPF codon 415, XPF nt 2063, ERCC6 codon 1213 or ERCC6 codon 1230. ORs for XPD and XPC genotypes were stronger for melanoma diagnosed at an early age, but tests for interaction were not statistically significant. The results provide further evidence for a role of XPD in the etiology of melanoma.

Cutaneous melanoma: pathogenesis and rationale for chemoprevention

OBJECTIVE

To critically review aspects of melanoma pathogenesis that lend themselves to a chemoprevention strategy. To discuss potential candidate chemoprevention agents with an emphasis on the lipid lowering drugs, the statins, currently, the most promising agents.

DATA SOURCES

A retrospective review of the literature.

STUDY SELECTION

Studies included those relevant to melanoma pathogenesis, to the scientific rationale of chemoprevention, and pertinent epidemiologic, pre-clinical, and clinical studies. The referenced study designs and methodologies varied.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by two reviewers, and the main results are presented in a quantitative descriptive manner.

CONCLUSION

Melanoma is a preventable disease by altering behavior (sun exposure) among at-risk individuals. There is also considerable evidence to suggest that melanoma development may be prevented or delayed by drugs of sufficiently low toxicity to make clinical trials of chemoprevention feasible and potentially successful. Among potential candidate agents, statins have compelling data for long-term safety and sufficient pre-clinical and clinical evidence for efficacy to justify their evaluation in well-designed trials in high-risk individuals, incorporating intermediate biologic endpoints.

MC1R, ASIP, and DNA Repair in Sporadic and Familial Melanoma in a Mediterranean Population

BACKGROUND

Melanoma risk factors include fair pigmentation, multiple nevi, low DNA repair capacity, and CDKN2A or CDK4 mutations. Variants of the melanocortin-1 receptor (MC1R) gene have been associated with fair pigmentation and melanoma risk, and a polymorphism of the Agouti Signaling Protein (ASIP) gene has been associated with dark pigmentation. We examined MC1R and ASIP genotypes in relation to phenotypic characteristics, sporadic and familial melanoma risk, and melanoma thickness as an indicator of disease progression in a Mediterranean population.

METHODS

We studied 267 melanoma patients and 382 control subjects from a case-control study and a family study in northeastern Italy. Host factors were assessed by physical examination, questionnaire, spectrophotometer, and minimal erythema dose measurement. MC1R was sequenced, ASIP was genotyped, and DNA repair capacity was measured by the host-cell reactivation assay. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression models. Effect modification of the association between MC1R and melanoma risk by phenotypic characteristics and DNA repair capacity was also assessed. All statistical tests were two-sided.

RESULTS

Carrying MC1R variant alleles was associated with a two- to fourfold increase in risk of both sporadic and familial melanoma compared with carrying wild-type MC1R, particularly in individuals carrying multiple variant alleles (OR = 3.9; 95% CI = 3.3 to 4.6). This association was stronger in individuals with fewer additional risk factors (those with dark skin or few nevi). MC1R variant allele carriers were also three to four times more likely than were non-carriers to have thick melanomas. The ASIP polymorphism was not associated with pigmentation, nevi, or melanoma risk.

CONCLUSIONS

MC1R was associated with melanoma risk and progression in a Mediterranean population, particularly in the absence of other strong risk factors, such as freckling or many nevi.

A Modified Host Cell Reactivation Assay to Measure DNA Repair Capacity for Removing 4-Aminobiphenyl Adducts: A Pilot Study of Bladder Cancer

As DNA repair plays an important role in genetic susceptibility to bladder cancer, assessment of the DNA repair phenotype is critical for the molecular epidemiology of bladder cancer. In this study, we developed and applied an assay using the luciferase (luc) reporter gene in a host-cell reactivation assay to measure DNA repair capacity for DNA damage induced by 4-aminobiphenyl (4-ABP), a well-studied aromatic amine and a known bladder carcinogen. We observed a dose-response relationship for 4-ABP dosage and DNA repair capacity (luc activity). We then applied this assay to measure DNA repair capacity in a pilot study of 89 pairs of bladder cancer patients and healthy controls matched by age, gender, and ethnicity, and we found that DNA repair capacity was significantly lower in cases than in controls (13.0% versus 14.4%; P = 0.006). Poor DNA repair capacity was associated with 3.42-fold increased bladder cancer risk. Further analysis revealed that intermediate and low levels of DNA repair capacity increased bladder cancer risk to 3.43-fold and 4.97-fold, respectively, compared with individuals with the most efficient DNA repair capacity. Moreover, ever smokers with suboptimal DNA repair capacity exhibited a 6.06-fold increased risk compared with never smokers with normal DNA repair capacity. In conclusion, our results support the hypothesis that deficient DNA repair capacity for 4-ABP induced DNA damage and increases bladder cancer risk. Our assay provides a new tool to specifically quantify DNA repair capacity in bladder cancer studies and, therefore, contributes to our goal of further elucidating bladder carcinogenesis.

Nucleotide-excision repair and prostate cancer risk

Prostate cancer (CaP) is the most commonly diagnosed nonskin cancer and the second leading cause of cancer death in American men. Its etiology is not fully understood. Ethnicity/race and family history are associated with it, and incidence increases with age. As with other solid tumors, accumulation of mutations and decline in DNA repair during aging may lead to CaP. However, we believe that conducting a large population screening for every cancer susceptibility gene (e.g. DNA repair) is only meaningful, if we can predict to what extent genetic variants contribute to DNA-repair functional phenotype and CaP risk. This review focuses on the association between CaP and nucleotide excision repair (NER), because some of the DNA adducts generated by CaP-related carcinogens are removed by the NER pathway, and our previous data showed a significant association between lower NER capacity (NERC) and CaP risk. Many laboratories, including ours, have employed a variety of approaches to evaluate the functional significance of DNA-repair single-nucleotide polymorphisms (SNPs) in human cancer risk assessment. Genetic profiling and computational modeling that can predict NERC may have great potential for CaP-risk assessment, because the current NERC assay is quite labor intensive, costly, and therefore not suitable for population-based screening.

Nucleotide excision repair as a marker for susceptibility to tobacco-related cancers: a review of molecular epidemiological studies

DNA repair is a complicated biological process consisting of several distinct pathways that play a central role in maintaining genomic stability. Research on DNA repair and cancer risk is a vital, emerging field that recently has seen rapid advances facilitated by the completion of the Human Genome Project. In this review, we described phenotypic and genotypic markers of nucleotide excision repair (NER) that have been used in molecular epidemiology studies. We summarized the population-based studies to date that have examined the association between DNA repair capacity phenotype and genetic polymorphisms of the NER genes and risk of tobacco-related cancers, including cancers of the lung, head and neck, prostate, bladder, breast, and esophagus. We also included studies of melanoma and nonmelanoma skin cancers because individuals with defective NER, such as patients with xeroderma pigmentosum (XP) are highly susceptible to ultraviolet light (UV)-induced melanoma and nonmelanoma skin cancers. The published data provide emerging evidence that DNA repair capacity may contribute to genetic susceptibility to cancers in the general population. However, many of the studies are limited in terms of the size of the study populations. Furthermore, all published findings are still considered preliminary, the assays used in the studies have yet to be validated, and the results need to be confirmed. Large and well-designed population-based studies are warranted to assess gene-gene and gene-environment interactions and to ultimately determine, which biomarkers of DNA repair capacity are useful for screening high-risk populations for primary prevention and early detection of tobacco-related cancers.

Pigmentary characteristics and moles in relation to melanoma risk

Although benign and atypical moles are considered key melanoma risk factors, previous studies of their influence were small and/or institution-based. We conducted a population-based case-control study in the state of New Hampshire. Individuals of ages 20-69 with an incident diagnosis of first primary cutaneous melanoma were ascertained through the New Hampshire State Cancer Registry. Controls were identified through New Hampshire driver's license lists and frequency-matched by age and gender to cases. We interviewed 423 eligible cases and 678 eligible controls. Host characteristics, including mole counts, were evaluated using logistic regression analyses. Our results showed that pigmentary factors, including eye color (OR = 1.57 for blue eyes compared to brown), hair color (OR = 1.85 for blonde/red hair color compared to brown/black), freckles before age 15 (OR = 2.39 for freckles present compared to absent) and sun sensitivity (OR = 2.25 for peeling sunburn followed by no tan or a light tan and 2.42 for sunburn followed by tan compared to tanning immediately), were related to melanoma risk; these associations held after adjustment for sun-related factors and for moles. In analyses confined to skin examination participants, the covariate-adjusted effects of benign and atypical moles were moderately strong. Compared to 0-4 benign moles, risk increased steadily for 5-14 moles (OR = 1.71), 15-24 moles (OR = 3.55) and >or= 25 moles (OR = 4.33). Risk also increased with the number of atypical moles; compared to none, the ORs for having 1, 2-3, or >or= 4 atypical moles were 2.08, 1.84 and 3.80, respectively. Although risk was highest for those with multiple benign and atypical moles, the interaction was not of statistical significance. Our findings, arising from the first population- and incidence-based study to evaluate atypical moles in relation to melanoma risk, confirm the importance of host susceptibility, represented by pigmentary factors and the tendency to develop benign or atypical moles, in the etiology of this disease.

Meta-analysis of risk factors for cutaneous melanoma: I. Common and atypical naevi

A systematic meta-analysis of observational studies of melanoma and one of the most important risk factors, the number of naevi, was conducted in order to clarify aspects of the aetiology of this disease. Following a systematic literature search, relative risks (RRs) were extracted from 46 studies published before September 2002. Dose-response random effects models were used to obtain pooled estimates. Sub-group analysis and meta-regression were carried out to explore sources of between-study variation and bias. Sensitivity analyses investigated the reliability of the results and any publication bias. Number of common naevi was confirmed an important risk factor with a substantially increased risk associated with the presence of 101-120 naevi compared with <15 (pooled Relative Risk (RR) = 6.89; 95% Confidential Interval (CI): 4.63, 10.25) as was the number of atypical naevi (RR = 6.36 95%; CI: 3.80, 10.33; for 5 versus 0). The type of study and source of cases and controls were two study characteristics that significantly influenced the estimates. Case-control studies, in particular when the hospital was the source for cases or controls, appeared to present much lower and more precise estimates than cohort studies.

Bronzeamento e risco de melanoma cutâneo: revisão da literatura

Estudos epidemiológicos sugerem a relação entre comportamentos relacionados ao bronzeamento e risco elevado de melanoma. Nesse sentido, realizou-se revisão sobre essa temática que abrangeu o período correspondente aos anos de 1977 a 1998. Foram pesquisadas as bases de dados Medline e Embase (Excerpta Medica). A análise mostrou que entre os jovens, apesar do conhecimento sobre os riscos da exposição excessiva à radiação ultravioleta e sobre as práticas visando à proteção da pele, prevalece o hábito de expor-se intencionalmente ao sol. Esse hábito é alimentado por crenças e atitudes em relação ao bronzeado e estimulado por influência do grupo e de pessoas consideradas "referências". As práticas mais freqüentemente adotadas para bronzear a pele apresentam risco elevado para o desenvolvimento de melanoma. Conclui-se que a forma mais eficaz de prevenir o melanoma é divulgar nos meios de comunicação que a pele bronzeada não é saudável, pois foi danificada pela radiação ultravioleta solar; e iniciar campanhas com ações efetivas para mudar comportamentos, naquilo que os motiva e os alimenta.

Variability in nomenclature used for nevi with architectural disorder and cytologic atypia (microscopically dysplastic nevi) by dermatologists and dermatopathologists

BACKGROUND

Although a nevus with the microscopic features of a "dysplastic nevus" is commonly seen, the nomenclature used to describe such a lesion has been thought to be inconsistent. A 1992 National Institutes of Health (NIH) Consensus Conference sought to unify nomenclature and suggested that the term "nevus with architectural disorder" be used along with a comment on melanocytic atypia.

METHODS

We performed a cross-sectional mail survey to determine preferred terminology as well as the level of adherence to the NIH-recommended nomenclature. All 856 active members of the American Society of Dermatopathology (ASDP) and 1100 (13.0%) of the 8471 active members of the American Academy of Dermatology (AAD) were surveyed.

RESULTS

Five hundred and thirty-three ASDP members and 483 AAD members who fulfilled eligibility criteria completed the questionnaire. The term "dysplastic nevus" was favored by the largest number of responders (favored by 39.1% of ASDP members and 62.3% of AAD members), while the 1992 NIH Consensus Conference-recommended terminology was the second most popular term (25.3% of ASDP and 15.1% of AAD members). Dermatopathologists (OR = 1.9, p = 0.0001) and those who had dual training in dermatology and dermatopathology (OR = 1.6, p = 0.02 for ASDP members; OR = 2.3, p = 0.02 for AAD members) were more likely to adhere to the 1992 NIH Consensus Conference nomenclature.

CONCLUSIONS

Despite attempts to unify nomenclature for microscopically dysplastic nevi through the NIH Consensus Conference, wide variation in terminology persists.

Deficient nucleotide excision repair capacity enhances human prostate cancer risk

Prostate cancer (CaP) is the most commonly diagnosed non-skin cancer and the second leading cause of cancer death in American men. The etiology of CaP is not fully understood. Because most of the DNA adducts generated by some CaP-related carcinogens, including polycyclic aromatic hydrocarbons, heterocyclic amines, and pesticides, are removed by the nucleotide excision repair (NER) pathway, we pilot tested the hypothesis that CaP is associated with deficient NER capacity (NERC), measured by a plasmid-based host reactivation assay. Using cryopreserved lymphocytes collected in an ongoing, clinic-based case-control study, our results showed that the mean NERC was significantly lower (P = 0.03) in 140 cases (mean +/- SD, 8.06 +/- 5.17) than in 96 controls (9.64 +/- 5.49). There was a significant association between below-median NERC and CaP risk: odds ratio (OR), 2.14; 95% confidence interval (CI), 1.19-3.86, after adjustment for age, race/ethnicity, smoking history, benign prostatic hyperplasia, and family history. This association was stronger in younger (<60 years of age) subjects (OR, 3.98; 95% CI, 1.13-14.02) compared with older (> or = 60) subjects (OR, 1.74; 95% CI, 0.90-3.37). When we stratified NERC values by quartiles of controls, there was a significant dose-dependent association between lower NERC and elevated CaP risk (p (test for linear trend), 0.01). Compared with the highest quartile of NERC as the referent group, the adjusted ORs for the 75th, 50th, and 25th quartiles were: 1.09 (95% CI, 0.46-2.59); 1.81 (95% CI, 0.77-4.27); and 2.63 (95% CI, 1.17-5.95), respectively. This pilot study is the first direct evidence associating deficient NERC with human CaP risk.

XPD gene polymorphism and host characteristics in the association with cutaneous malignant melanoma risk

We recently reported an association between low DNA repair capacity, measured through the host-cell reactivation assay, and melanoma risk in subjects with dysplastic naevi or low tanning ability. We investigated the genetic basis for these findings by analysing the Asp312Asn and Lys751Gln polymorphisms of the XPD (ERCC2) DNA repair gene in the same subjects. Similar to our previous report, no significant association between XPD polymorphisms and melanoma risk was found in 176 melanoma cases and 177 controls (odds ratio (OR)=1.5, 95% confidence interval (CI)=0.9–2.5 for 312Asn; OR=1.3, 95% CI=0.8–2.1 for 751Gln, adjusted for age, gender, dysplastic naevi and pigmentation characteristics). However, XPD variants were associated with increased risk in older (>50 years) subjects (OR=3.4, 95% CI=1.6–7.3 for 312Asn; OR=2.3, 95% CI=1.1–4.9 for 751Gln). The 751Gln allele was associated with elevated melanoma risk among subjects without dysplastic naevi (OR=2.6, 95% CI=1.1–6.4). Subjects with low tanning ability and XPD variants exhibited a nonsignificant increase of melanoma risk (OR=2.3, 95% CI=0.7–7.0 for 312Asn; OR=3.0, 95% CI=1.0–8.8 for 751Gln). DNA repair capacity was slightly decreased in subjects carrying 751Gln alleles. XPD variants may modify melanoma risk in subjects with specific host characteristics, such as older age, lack of dysplastic naevi or low tanning ability.

DNA repair and breast carcinoma susceptibility in women

BACKGROUND

Breast carcinoma is the most common cancer and the second leading cause of cancer-related deaths among women. The disease represents approximately 31% of all cancers in Puerto Rican women. Several DNA repair pathways are involved in preventing carcinogenesis. The current study evaluated the hypothesis that a reduced DNA repair capacity (DRC) is a susceptibility factor for breast carcinoma.

METHODS

A retrospective case-control clinical study was performed to compare age-matched DRC in 33 women with histopathologically confirmed breast carcinoma (cases) and 47 cancer-free women (controls). DRC was measured using a host cell reactivation assay with a luciferase reporter gene and then transfected into human peripheral lymphocytes. A questionnaire was used to solicit breast carcinoma risk factors.

RESULTS

Women with breast carcinoma had a mean DRC of 5.6% +/- 0.5 standard error of the mean (SEM). Cancer cases had a 36% reduction (P<0.001) in DRC when compared with the control group (DRC=8.7% +/- 0.7 SEM). Younger participants with breast carcinoma were found to have a more significant reduction in DRC when compared with age-matched controls. Family (odds ratio [OR]=4.1), maternal lineage (OR=5.5), and maternal (OR=12.4) history of breast carcinoma were found to be the only statistically significant (P<0.05) risk factors associated with the disease.

CONCLUSIONS

The findings supported the hypothesis that a low DRC is a susceptibility factor for breast carcinoma. A 1% decrease in DRC corresponded to a 22% increase in breast carcinoma risk. To the authors' knowledge, the current study was the first to directly determine the DRC of women with breast carcinoma. Because DRC is an independent risk factor for breast carcinoma, the DRC of women may be a useful marker in predicting susceptibility.