Genetic polymorphism in Methylenetetrahydrofolate Reductase chloride transport protein 6 (MTHFR CLCN6) gene is associated with keratinocyte skin cancer in a cohort of renal transplant recipients.

Background: Renal transplant recipients (RTRs) are at increased risk of keratinocyte cancer (KC), especially cutaneous squamous cell carcinoma (cSCC). Previous studies identified a genetic variant of the Methylenetetrahydrofolate Reductase (MTHFR) gene, C677T, which conferred a risk for diagnosis of cSCC in Irish RTRs. Objective: We sought to find further genetic variation in MTHFR and overlap genes that may be associated with a diagnosis of KC in RTRs. Methods: Genotyping of a combined RTR population (n = 821) from two centres, Ireland (n = 546) and the USA (n = 275), was performed. This included 290 RTRs with KC and 444 without. Eleven single nucleotide polymorphisms (SNPs) in the MTHFR gene and seven in the overlap gene MTHFR Chloride transport protein 6 (CLCN6) were evaluated and association explored by time to event analysis (from transplant to first KC) using Cox proportional hazards model. Results: Polymorphism at MTHFR CLCN6 (rs9651118) was significantly associated with KC in RTRs (HR 1.50, 95% CI 1.17-1.91, p < 0.00061) and cSCC (HR 1.63, 95% CI 1.14-2.34, p = 0.007). A separate SNP, MTHFR C677T, was also significantly associated with KC in the Irish population (HR 1.31, 95% CI 1.05-1.63, p = 0.016), but not American RTRs. Conclusions: We report the association of a SNP in the MTHFR overlap gene, CLCN6 and KC in a combined RTR population. While the exact function of CLCN6 is not known, it is proposed to be involved in folate availability. Future applications could include incorporation in a polygenic risk score for KC in RTRs to help identify those at increased risk beyond traditional risk factor assessment.

CERKL is upregulated in cutaneous squamous cell carcinoma and maintains cellular sphingolipids and resistance to oxidative stress.

BACKGROUND: Ceramide kinase-like protein (CERKL) was originally described in retinal tissue. CERKL has been shown to protect cells from oxidative stress, and mutations in CERKL underlie the inherited disease retinitis pigmentosa. CERKL expression maintains cellular sphingolipids via an unknown mechanism. OBJECTIVES: To determine whether CERKL is expressed in epidermis and cutaneous squamous cell carcinoma (cSCC) and whether CERKL expression affects cSCC sphingolipid metabolism and susceptibility to oxidative stress. METHODS: CERKL expression was determined by RNA-Seq, quantitative polymerase chain reaction and immunohistochemistry. CERKL was knocked down in cSCC cells using small interfering RNA. Sphingolipid content was analysed by liquid chromatography-mass spectrometry. Oxidative stress was induced by treatment with H2 O2 , and apoptosis was measured using flow cytometry to determine annexin V binding. RESULTS: CERKL mRNA and protein are highly expressed in actinic keratosis and cSCC in comparison with normal epidermis. CERKL is also expressed in metabolically active epithelial cells in normal hair bulbs and sebaceous glands. CERKL knockdown in cultured cSCC cells reduces cellular sphingolipid content and enhances susceptibility to oxidative stress. CONCLUSIONS: These findings suggest that CERKL may be important in cSCC progression and could lead to novel strategies for prevention and treatment of cSCC.

CERKL is Upregulated in Cutaneous Squamous Cell Carcinoma and Maintains Cellular Sphingolipids and Resistance to Oxidative Stress.

BACKGROUND: Ceramide Kinase-Like Protein (CERKL) was originally described in retinal tissue. CERKL has been shown to protect cells from oxidative stress, and mutations in CERKL underlie the inherited disease, retinitis pigmentosa. CERKL expression maintains cellular sphingolipids via an unknown mechanism. OBJECTIVES: To determine whether CERKL is expressed in epidermis and cutaneous squamous cell carcinoma (cSCC) and whether CERKL expression affects cSCC sphingolipid metabolism and susceptibility to oxidative stress. METHODS: CERKL expression was determined by RNA-Seq, qPCR and immunohistochemistry. CERKL was knocked down in cSCC cells using siRNA. Sphingolipid content was analyzed by liquid chromatography-mass spectrometry (LC-MS). Oxidative stress was induced by treatment with H2 O2 , and apoptosis was measured using flow cytometry to determine annexin v binding. RESULTS: CERKL mRNA and protein are highly expressed in actinic keratosis and cSCC in comparison with normal epidermis. CERKL also is expressed in metabolically active epithelial cells in normal hair bulbs and sebaceous glands. CERKL knockdown in cultured cSCC cells reduces cellular sphingolipid content and enhances susceptibility to oxidative stress. CONCLUSIONS: These findings suggest that CERKL may be important in cSCC progression and could lead to novel strategies for prevention and treatment of cSCC.

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.

Variants at the OCA2/HERC2 locus affect time to first cutaneous squamous cell carcinoma in solid organ transplant recipients collected using two different study designs.

BACKGROUND: Variants at the oculocutaneous albinism 2 (OCA2)/HECT and RLD domain containing E3 ubiquitin protein ligase 2 (HERC2) locus have been associated with pigmentation phenotypes and risk of developing several types of skin cancer. OBJECTIVES: To evaluate OCA2/HERC2 locus variants for their impact on time to develop cutaneous squamous cell carcinoma (cSCC) in organ transplant recipients (OTRs) who are at elevated risk of developing cSCC. METHODS: Participants were solid OTRs ascertained from two centres (n = 125 and 261) with an average of 13·1 years of follow-up post-transplant. DNA was available for genotyping for all participants, in addition to medical records and questionnaire data. The Ohio State University study had a case-control design with prospective follow-up, and the University of California San Francisco study was a national cross-sectional survey with retrospective chart review. RESULTS: OCA2 variants rs12913832 and rs916977 were significantly associated with time to first cSCC post-transplant. OTRs homozygous for the brown-eye alleles of rs916977 (GG) and rs12913832 (AA) had significant delays of time to first cSCC post-transplant compared with individuals homozygous for the blue-eye alleles (hazard ratio 0·34, P < 0·001 and hazard ratio 0·54, P = 0·012, respectively). Both variants were highly associated with eye colour in the combined studies (P < 0·001). CONCLUSIONS: This study is the first to show an association between OCA2/HERC2 variants and time to first cSCC post-transplant. This may impact dermatological screening recommendations for high-risk populations.

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.

Induction Hedgehog pathway inhibition followed by combined-modality radiotherapy for basal cell carcinoma.

Basal cell carcinoma (BCC), the most common cancer in the U.S.A., is treated primarily with local excision. In some cases, lesion size, location or extent prevent complete resection. Locally advanced BCC responds to systemic therapy with the Hedgehog pathway inhibitor vismodegib, but withdrawal of treatment may result in disease relapse. Here we present a case of locally advanced auricular BCC treated with induction vismodegib and radiation, resulting in durable local control and an acceptable level of acute toxicity.

Practice variation in Aspergillus prophylaxis and treatment among lung transplant centers: a national survey.

BACKGROUND: Fungal infections remain a substantial cause of mortality in lung transplant (LTx) recipients, yet no comprehensive consensus guidelines have been established for antifungal prophylaxis and treatment of Aspergillus infection in these patients. METHODS: A cross-sectional study surveyed the directors from 27 of 64 (45.5%) active LTx centers in the United States to examine clinical practice variations in Aspergillus prophylaxis and treatment of colonization and invasive aspergillosis (IA) in LTx recipients. RESULTS: Antifungal prophylaxis increased from 52.3% in 2011 to 77.8% in 2013, with the most common agent being inhaled amphotericin B (61.9%), followed by oral voriconazole (51.9%). A total of 74.1% of centers treat Aspergillus airway colonization, with 80.0% of centers using oral voriconazole. All centers treat IA, with 92.6% using oral voriconazole. The duration of Aspergillus prophylaxis and treatment of colonization or IA varied widely across centers from 3 months to >1 year. A total of 51.9% of centers reported internal practice variations in the treatment of IA. Factors guiding treatment decisions included microbiologic culture and sensitivity (74.1%), ease of administration (59.3%), interaction with other medications (55.5%), side effect profile (51.8%), and center guidelines (48.1%). Although 85.2% of LTx centers recommended routine skin cancer screening for LTx recipients, only 44.4% of LTx centers reported having a dedicated transplant dermatologist. CONCLUSION: Most active US LTx centers currently employ antifungal prophylaxis and treat Aspergillus colonization and IA, although choice of agent, route of administration, and duration of therapy across and within centers continue to differ substantially. The number of transplant dermatologists available among US LTx centers is limited. Overall, a strong need exists for more comprehensive consensus guidelines to direct antifungal prophylaxis and treatment of Aspergillus infection in LTx recipients.

Single-nucleotide polymorphisms in pigment genes and nonmelanoma skin cancer predisposition: a systematic review.

Nonmelanoma skin cancer (NMSC) is the most common cancer in the U.S.A. The two most common NMSCs are basal cell carcinoma and squamous cell carcinoma. The associations of single-nucleotide polymorphisms (SNPs) in pigmentation pathway genes with NMSC are not well characterized. There is a series of epidemiological studies that have tested these relationships, but there is no recent summary of these findings. To explain overarching trends, we undertook a systematic review of published studies. The summarized data support the concept that specific SNPs in the pigmentation pathway are of importance for the pathogenesis of NMSC. The SNPs with the most promising evidence include MC1R rs1805007(T) (Arg151Cys) and rs1805008(T) (Arg160Trp), and ASIP AH haplotype [rs4911414(T) and rs1015362(G)]. There are a few other SNPs found in TYR, OCA2 and SLC45A2 that may show additional correlation after future research. With additional research there is potential for the translation of future findings to the clinic in the form of SNP screenings, where patients at high risk for NMSC can be identified beyond their phenotype by genotypically screening for predisposing SNPs.

Factors affecting sunscreen use and sun avoidance in a U.S. national sample of organ transplant recipients.

BACKGROUND: Organ transplant recipients have an increased risk of nonmelanoma skin cancers due to immunosuppressive therapy following transplantation. Use of sunscreen has been shown to reduce this risk. OBJECTIVES: To identify patient and healthcare factors associated with sun-protective behaviours in organ transplant recipients after transplantation with the goal of increasing overall sunscreen use. METHODS: This study utilized a cross-sectional, retrospective survey from a national sample of 198 organ transplant recipients in the U.S.A. from 2004 to 2008 with no prior diagnosis of skin cancer. The main outcome measures were sunscreen use and sun avoidance before and after transplantation. Frequency of sunscreen use and sun exposure was obtained by self-report on Likert scales ranging from never to always, and these responses were converted to a numerical scale from 0 to 4. RESULTS: Overall sunscreen use increased after transplantation (from a score of 1·4 to 2·1, P < 0·001). Sex, Fitzpatrick skin type, receiving advice to avoid sun from a healthcare provider, and pretransplantation sunscreen use were significantly associated with frequency of post-transplantation sunscreen use in multivariate models. Pretransplantation sun exposure, advice to avoid sun and pretransplantation sunscreen use were significantly associated with sun avoidance post-transplantation. CONCLUSIONS: Both patient features and clinician advice are associated with sun-protective behaviours after organ transplantation. These results will help physicians target expanded sun-protection counselling to those patients most in need of such intervention.