Genome-wide association studies and polygenic risk scores for skin cancer: clinically useful yet?

BACKGROUND: Genome-wide association studies (GWAS) have identified thousands of susceptibility variants, although most have been associated with small individual risk estimates that offer little predictive value. However, combining multiple variants into polygenic risk scores (PRS) may be more informative. Multiple studies have developed PRS composed of GWAS-identified variants for cutaneous cancers. This review highlights data from these studies. OBJECTIVES: To review published GWAS and PRS studies for melanoma, cutaneous squamous cell carcinoma (cSCC) and basal cell carcinoma (BCC), and discuss their potential clinical utility. METHODS: We searched PubMed and the National Human Genome Research Institute-European Bioinformatics Institute GWAS catalogue to identify relevant studies. RESULTS: Results from 21 GWAS (11 melanoma, 3 cSCC, 7 BCC) and 11 PRS studies are summarized. Six loci in pigmentation genes overlap between these three cancers (ASIP/RALY, IRF4, MC1R, OCA2, SLC45A2 and TYR). Additional loci overlap for cSCC/BCC and BCC/melanoma, but no other loci are shared between cSCC and melanoma. PRS for melanoma show roughly two-to-threefold increases in risk and modest improvements in risk prediction (2-7% increases). PRS are associated with twofold and threefold increases in risk of cSCC and BCC, respectively, with small improvements (2% increase) in predictive ability. CONCLUSIONS: Existing data indicate that PRS may offer small, but potentially meaningful, improvements to risk prediction. Additional research is needed to clarify the potential utility of PRS in cutaneous carcinomas. Clinical translation will require well-powered validation studies incorporating known risk factors to evaluate PRS as tools for screening. What's already known about this topic? Over 50 susceptibility loci for melanoma, basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) have been identified in genome-wide association studies (GWAS). Polygenic risk scores (PRS) using variants identified from GWAS have also been developed for melanoma, BCC and cSCC, and investigated with respect to clinical risk prediction. What does this study add? This review provides an overview of GWAS findings and the potential clinical utility of PRS for melanoma, BCC and cSCC.

Photosensitizing antihypertensive drug use and risk of cutaneous squamous cell carcinoma.

BACKGROUND: Many antihypertensive drugs (ADs) are photosensitizing, heightening reactivity of the skin to sunlight. Photosensitizing ADs have been associated with lip cancer, but whether they impact the risk of cutaneous squamous cell carcinoma (cSCC) is unknown. OBJECTIVES: To examine the association between AD use and cSCC risk among a cohort of non-Hispanic white individuals with hypertension enrolled in a comprehensive integrated healthcare delivery system in northern California (n = 28 357). METHODS: Electronic pharmacy data were used to determine exposure to ADs, which were classified as photosensitizing, nonphotosensitizing or unknown, based on published literature. We identified patients who developed a cSCC during follow-up (n = 3010). We used Cox modelling to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Covariates included age, sex, smoking, comorbidities, history of cSCC and actinic keratosis, survey year, healthcare utilization, length of health plan membership and history of photosensitizing AD use. RESULTS: Compared with nonuse of ADs, risk of cSCC was increased with ever having used photosensitizing ADs (aHR = 1·17, 95% CI 1·07-1·28) and ever having used ADs of unknown photosensitizing potential (aHR = 1·11, 95% CI 1·02-1·20), whereas no association was seen with ever having used nonphotosensitizing ADs (aHR = 0·99; 95% CI 0·91-1·07). Additionally, there was a modest increased risk with an increased number of prescriptions for photosensitizing ADs (aHR = 1·12, 95% CI 1·02-1·24; aHR = 1·19, 95% CI 1·06-1·34; aHR = 1·41, 95% CI 1·20-1·67 for one to seven, eight to 15 and ≥ 16 fills, respectively). CONCLUSIONS: These findings provide moderate support for an increased cSCC risk among individuals treated with photosensitizing ADs.

Prognostic factors and survival in acral lentiginous melanoma.

BACKGROUND: Acral lentiginous melanoma (ALM) is a rare melanoma subtype that disproportionately afflicts people of colour. ALMs have a worse prognosis than other melanoma subtypes; this has been attributed to aggressive biological behaviour, more advanced stage at presentation and possible disparities in access to health care. OBJECTIVES: To examine, using comprehensive patient data and long-term follow-up information in a well-characterized cohort, how patient, tumour and clinical management variables impact overall and melanoma-specific survival. METHODS: We characterized a consecutive cohort of 123 ALMs diagnosed from 1987 to 2013 and analysed predictors of overall and melanoma-specific survival for their association with survival. RESULTS: Univariate hazard ratios and 95% confidence intervals using Cox regression models showed that increased Breslow depth, presence of ulceration, receipt of radiation, chemo- and vaccine therapy were associated with worse melanoma-specific survival. Notably, nonwhite race/ethnicity was not associated with worse overall or melanoma-specific survival. Multivariate modelling adjusting for patient, tumour and management variables revealed Breslow depth > 2 mm and disease extent as significantly associated with poor melanoma-specific survival. CONCLUSIONS: Melanoma-specific mortality among patients with ALM is associated with increased tumour thickness and more advanced stage at presentation, but not with race/ethnicity. Advanced tumour features at presentation and access to care may account for less favourable survival outcomes reported among nonwhite patients.

Research gaps in the management and prevention of cutaneous squamous cell carcinoma in organ transplant recipients.

Although tremendous progress has been made in recent years in skin cancer care for organ transplant recipients, significant gaps remain in data-driven clinical guidelines, particularly for the treatment and prevention of cutaneous squamous cell carcinoma (cSCC), the most common malignancy among this population. In this review, we aim to summarize current knowledge around the management of cSCC and highlight the most significant gaps in knowledge that continue to pose challenges in the delivery of skin cancer care for organ transplant recipients. We suggest future directions for research that will bridge existing gaps and establish evidence-driven guidelines for primary prevention, screening and treatment of cSCC in this high-risk patient population.

Risk prediction tools for keratinocyte carcinoma after solid organ transplantation: a review of the literature.

Long-term iatrogenic immunosuppression increases the risk of cutaneous malignancies in organ transplant recipients (OTRs), particularly the keratinocyte cancers basal cell carcinoma and cutaneous squamous cell carcinoma (cSCC). cSCC is the most common malignancy in OTRs, with the risk increased to over 65-fold in transplanted patients relative to the general population. There have been very few risk prediction tools developed for accurate determination of the risk of developing keratinocyte cancers in the OTR population. This review summarizes the prediction tools developed to date, and outlines future directions for developing more accurate prediction models that are clinically useful for the transplant physician and dermatologist.

Voriconazole Exposure and Risk of Cutaneous Squamous Cell Carcinoma, Aspergillus Colonization, Invasive Aspergillosis and Death in Lung Transplant Recipients.

Voriconazole is a triazole antifungal used to prevent and treat invasive fungal infections after lung transplantation, but it has been associated with an increased risk of developing cutaneous squamous cell carcinoma (SCC). Despite widespread use, there are no clear guidelines for optimal prophylactic regimens that balance the competing risks and benefits. We conducted a retrospective cohort study of all lung transplant recipients at the University of California, San Francisco, who were transplanted between October 1991 and December 2012 (n = 455) to investigate whether voriconazole exposure affected development of SCC, Aspergillus colonization, invasive aspergillosis and all-cause mortality. Voriconazole exposure was associated with a 73% increased risk of developing SCC (hazard ratio [HR] 1.73; 95% confidence interval [CI]: 1.04-2.88; p = 0.03), with each additional 30-day exposure at the standard dose increasing the risk by 3.0% (HR 1.03; 95% CI: 1.02-1.04; p < 0.001). Voriconazole exposure reduced risk of Aspergillus colonization by 50% (HR 0.50; 95% CI: 0.34-0.72; p < 0.001), but we were underpowered to detect risk reduction for invasive aspergillosis. Voriconazole exposure significantly reduced all-cause mortality among subjects who developed Aspergillus colonization (HR 0.34; 95% CI: 0.13-0.91; p = 0.03) but had no significant impact on those without colonization. Physicians should consider patient-specific factors that modify the potential risks and benefits of voriconazole for the care of lung transplant recipients.

Sebotropic eruption associated with use of oral kava kava supplement.

Supplement use is prevalent, and its use is increasing among older adults. Dermatologists need to be aware of the adverse cutaneous effects that can result from herbal supplement use. A 55-year-old man presented with an eruption in a sebotropic distribution after consuming kava kava for 3 weeks, which resolved after discontinuation of the supplement. This case highlights the need for clinicians to consider kava kava in the differential of sebotropic eruptions. The biology, mechanism of action, and potential systemic and cutaneous effects of kava kava are reviewed.

Initiation of TNF inhibitor therapy and change in physiologic measures in psoriasis.

BACKGROUND: Psoriasis may predispose to cardiovascular disease and diabetes. However, the role of tumor necrosis factor (TNF) inhibitor in mediating this risk is controversial. OBJECTIVE: To assess this relationship, we estimated change in metabolic physiologic measures before and after initiation of TNF inhibitor therapy compared with methotrexate (MTX) therapy among psoriasis patients. METHODS: We conducted a retrospective cohort study, 2007-2012, using computerized clinical data for 1274 new users of TNF inhibitor and 979 new users of MTX therapy to compare change in blood pressure, lipids, triglycerides, fasting plasma glucose and body mass index (BMI) before and after start of TNF inhibitors or MTX. The study was restricted to new users. We computed within-person change in each measure, so that each patient served as their own control. In addition, we compared TNF inhibitor patients to MTX patients, by computing the adjusted difference in their group means. In secondary analyses, we examined phototherapy as a comparator. RESULTS: Among starters of TNF inhibitor and MTX therapy, within-person change in physiologic measures at 6 months did not differ significantly. We observed no important or significant changes in any of the physiologic measures with initiation of TNF inhibitor compared with MTX. The same results were found in subgroup analyses focused on men, and on those with hypertension, diabetes mellitus, or obesity. The same results were observed with phototherapy, except that diastolic blood pressure declined by 0.6 mmHg within person during the 6 months after starting phototherapy (P < 0.05). CONCLUSIONS: The study provides no evidence for improvement of physiologic measures associated with the metabolic syndrome resulting from TNF inhibitor use for psoriasis.

Association of ambient air quality with children's lung function in urban and rural Iran.

During the summer of 1994, a cross-sectional epidemiological study, in which the pulmonary function of children in Tehran was compared with pulmonary function in children in a rural town in Iran, was conducted. Four hundred children aged 5-11 y were studied. Daytime ambient nitrogen dioxide, sulfur dioxide, and particulate matter were measured with portable devices, which were placed in the children's neighborhoods on the days of study. Levels of these ambient substances were markedly higher in urban Tehran than in rural areas. Children's parents were questioned about home environmental exposures (including heating source and environmental tobacco smoke) and the children's respiratory symptoms. Pulmonary function was assessed, both by spirometry and peak expiratory flow meter. Forced expiratory volume in 1 s and forced vital capacity-as a percentage of predicted for age, sex and height-were significantly lower in urban children than in rural children. Both measurements evidenced significant reverse correlations with levels of sulfur dioxide, nitrogen dioxide, and particulate matter. Differences in spirometric lung function were not explained by nutritional status, as assessed by height and weight for age, or by home environmental exposures. Reported airway symptoms (i.e., cough, phlegm, and wheeze) were higher among rural children, whereas reported physician diagnosis of bronchitis and asthma were higher among urban children. The association between higher pollutant concentrations and reduced pulmonary function in this urban-rural comparison suggests that there is an effect of urban air pollution on short-term lung function and/or lung growth and development during the preadolescent years.

Spontaneous splenic rupture in infectious mononucleosis: a review.

Spontaneous rupture of the spleen is a rare complication of infectious mononucleosis (IM) occurring in 0.1-0.5 percent of patients with proven IM [1]. Although splenectomy has been advocated as the definitive therapy in the past, numerous recent reports have documented favorable outcomes with non-operative management. A review of the literature suggests that non-operative management can be successful if appropriate criteria, such as hemodynamic stability and transfusion requirements are applied in patient selection. We report the case of a 36 year old man with infectious mononucleosis who had a spontaneous splenic rupture and who was successfully managed by splenectomy. Based on review of the literature, an approach to management of a spontaneously ruptured spleen secondary to IM is suggested.

The vessel loop shoelace technique for closure of fasciotomy wounds.

Compartment syndrome of the extremity may occur after severe trauma secondary to fractures, vascular ischemia, crush, or electrical injury. Treatment consists of expedient fasciotomy to avoid permanent injury to muscles or nerves. Management of the wounds postoperatively has consisted traditionally of primary closure, healing by secondary intention, or split-thickness skin grafting to cover defects. The fasciotomy wound may remain substantial secondary to soft-tissue swelling and edema. The authors present an alternative protocol for fasciotomy wound management, consisting of gradual closure with progressive tension using vessel loops. The vessel loops are placed intraoperatively during the compartment release and are attached to the wound margins using standard skin staples. The loops are tightened progressively postoperatively during routine dressing changes, resulting in closure of the wound within 2 weeks. The advantages over split-thickness grafting include avoidance of donor morbidity and better cosmesis. Sporadic case reports using similar techniques have been published in the orthopedic literature with comparable results. The current series includes 37 patients, ages 9 to 48 years, who were treated for open fasciotomy. There were 11 upper extremity and 26 lower extremity wounds treated, all of which were closed within 3 weeks.

Expression and localization of thymidine phosphorylase/platelet-derived endothelial cell growth factor in skin and cutaneous tumors.

Thymidine phosphorylase/platelet-derived endothelial cell growth factor (TPase/PD-ECGF) is a catabolic enzyme that has been shown to be chemotactic for endothelial cells in vitro and angiogenic in vivo. TPase/PD-ECGF expression is increased in a variety of tumors. In the skin, TPase is active in normal keratinocytes in vitro and in vivo. Our objective was to study the expression and localization of TPase/PD-ECGF by immunohistochemical analysis in normal skin and cutaneous tumors and to correlate this information with enzymatic activity of TPase. TPase/PD-ECGF expression was observed in keratinocytes with intense staining of the infundibulum of hair follicles but no staining of hair bulbs. Expression localized primarily to the nucleus of keratinocytes in the basal layer but was more intense and cytoplasrmic in suprabasal keratinocytes. Increased expression of TPase/PD-ECGF in differentiated cells was confirmed by in vitro studies of TPase activity. In cutaneous tumors, there was positive staining for TPase/ PD-ECGF in squamous cell carcinomas (10/10), eccrine poromas (3/4), eccrine syringomas (4/4), trichoepitheliomas (1/3), and tumors of the follicular infundibulum (2/3) and melanomas (5/8). There was no staining of any intradermal nevi (0/2), basal cell carcinomas (0/10) or Merkel cell carcinoma (0/1). We conclude TPase/PD-ECGF is found throughout the epidermis and its expression increases with differentiation of keratinocytes. In cutaneous tumors, expression of TPase/PD-ECGF may be linked to the cell of origin of the tumor as well as the tumor's degree of differentiation.