Investigation of the Incidence and Geographic Distribution of Bone and Soft Tissue Sarcomas in Canada: A National Population-Based Study

Sarcomas are a heterogeneous group of mesenchymal malignancies with various genetic and environmental risk factors. This study analyzed the epidemiology of sarcomas to gain insight into the incidence and mortality rates of these cancers in Canada, as well as to elucidate their potential environmental risk factors. Data for this study were obtained from le Registre Québécois du Cancer (LRQC) and from the Canadian Cancer Registry (CCR) for the period from 1992 to 2010. Mortality data were obtained from the Canadian Vital Statistics (CVS) database for the period from 1992 to 2010 using the International Classification of Diseases for Oncology, ICD-O-3, ICD-9, or ICD-10 codes, for all subtypes of sarcomas. We found that the overall sarcoma incidence in Canada decreased during the study period. However, there were select subtypes with increasing incidence. Peripherally located sarcomas were found to have lower mortality rates compared to axially located sarcomas, as expected. Clustering of Kaposi sarcoma cases in self-identified LGBTQ+ communities and in postal codes with a higher proportion of African-Canadian and Hispanic populations was observed. Forward Sortation Area (FSA) postal codes with a lower socioeconomic status also had higher Kaposi sarcoma incidence rates.

Investigation of incidence and geographic distribution of gliomas in Canada from 1992 to 2010: a national population-based study highlighting the importance of exposure to airport operations

Background

Gliomas account for over two-thirds of all malignant brain tumors and have few established risk factors beyond family history and exposure to ionizing radiation. Importantly, recent studies highlighted the exposure to ultrafine particles (UFP) as a putative risk factor for malignant brain tumors.

Methods

Clinical and geographic data encompassing all provinces and territories from 1992 to 2010 was obtained from the Canadian Cancer Registry and Le Registre Québécois du Cancer. Linear regression and joinpoint analyses were performed to assess incidence trends. Significantly higher and lower incidence postal codes were then interrogated using Standard Industrial Classification codes to detect significant industrial activity.

Results

In Canada, between 1992 and 2010, there were ~32,360 cases of glioma. Of these, 17,115 (52.9%) were glioblastoma. The overall crude incidence rates of 5.45 and 2.87 cases per 100,000 individuals per year for gliomas and glioblastomas, respectively, were identified. Our findings further revealed increasing crude incidence of gliomas/glioblastomas over time. A male predominance was observed. Provinces leading in glioma incidence included Quebec, Nova Scotia, and New Brunswick. Significantly lower crude incidence of glioma was found in Nunavut, Northwest Territories, Ontario, and Alberta. A putative regional clustering of gliomas was observed, with higher incidence rates in postal code areas correlating with industrial activity related to airport operations.

Conclusion

This study describes the geographic distribution of the glioma disease burden and, potentially, identifies industrial activity related to airport operations as potentially being associated with higher incidence of this cancer.

Identifying unmet needs and challenges in the definition of a plaque in mycosis fungoides: An EORTC-CLTG/ISCL survey

BACKGROUND

Consensus about the definition and classification of 'plaque' in mycosis fungoides is lacking.

OBJECTIVES

To delineate a comprehensive view on how the 'plaque' entity is defined and managed in clinical practice; to evaluate whether the current positioning of plaques in the TNMB classification is adequate.

METHODS

A 12-item survey was circulated within a selected panel of 22 experts (pathologists, dermatologists, haematologists and oncologists), members of the EORTC and International Society for Cutaneous Lymphoma. The questionnaire discussed clinical and histopathological definitions of plaques and its relationship with staging and treatment.

RESULTS

Total consensus and very high agreement rates were reached in 33.3% of questions, as all panellists regularly check for the presence of plaques, agree to evaluate the presence of plaques as a potential separate T class, and concur on the important distinction between plaque and patch for the management of early-stage MF. High agreement was reached in 41.7% of questions, since more than 50% of the responders use Olsen's definition of plaque, recommend the distinction between thin/thick plaques, and agree on performing a biopsy on the most infiltrated/indurated lesion. High divergence rates (25%) were reported regarding the possibility of a clinically based distinction between thin and thick plaques and the role of histopathology to plaque definition.

CONCLUSIONS

The definition of 'plaque' is commonly perceived as a clinical entity and its integration with histopathological features is generally reserved to specific cases. To date, no consensus is achieved as for the exact definition of thin and thick plaques and current positioning of plaques within the TNMB system is considered clinically inadequate. Prospective studies evaluating the role of histopathological parameters and other biomarkers, as well as promising diagnostic tools, such as US/RM imaging and high-throughput blood sequencing, are much needed to fully integrate current clinical definitions with more objective parameters.

Low-Intensity Visible and Near-Infrared Light-Induced Cell Signaling Pathways in the Skin: A Comprehensive Review

Objective: To describe current knowledge regarding established and putative cell signaling pathways involved in skin photobiomodulation. Background: The skin is the largest and most accessible organ of the body. It is the first line of defense against the external environment, including solar radiation. Among solar rays, visible and infrared non-ionizing photons may reach human skin and trigger a cascade of non-thermal cell signaling pathways called photobiomodulation (PBM). The use of PBM using artificial light sources has been known for more than 50 years, but it has not yet been widely accepted due to uncertainty about the cellular mechanisms of action. However, much knowledge has been gained in this field in recent years, which will be summarized in this review. Methods: An extensive literature review was performed using Medline, Embase, and Google Scholar as research databases to acquire relevant publications in this particular field. Results: A comprehensive description of chromophores, primary and secondary effectors is provided in addition to a visual representation of known and putative cell signaling mechanisms involved in such complex light-skin interactions. Also, a summary of clinical indications of skin PBM, key light parameters, and promising skin applications (local and systemic) are mentioned. Conclusions: In PBM, skin cells are the first to absorb photons, triggering specific cell-signaling pathways through primary and secondary effectors, leading to enhanced cell repair and survival, notably in hypoxic or stressed cells. A better understanding of the mechanisms of action will help us optimize known indications and discover new ones.

Cutaneous T-cell lymphoma developing in surgical scars post cardiac surgery: A case study

Cutaneous T-cell lymphomas are a class of non-Hodgkin lymphomas characterized by the infiltration of malignant T cells into the skin. Their precise pathogenesis remains incompletely understood, but persistent and specific antigen stimulation of skin-homing CD4+ memory T cells by external or internal factors, combined with an inflammatory cytokine-rich tissue microenvironment, may be critical in the development of cutaneous T-cell lymphomas. We present herein a case of primary cutaneous T-cell lymphoma arising in two surgical scars that developed 6 months post-operatively and were successfully treated with external beam radiotherapy. This case highlights the notion that primary cutaneous T-cell lymphoma can develop locally at the site of injury/foreign body within a relatively short time post trauma/surgery. This work contributes to the literature of cutaneous T-cell lymphomas arising after a trauma, surgery, or a foreign body.

Pharmacological Agents Used in the Prevention and Treatment of Actinic Keratosis: A Review

Actinic keratosis (AK) is among the most commonly diagnosed skin diseases with potentially life-threatening repercussions if left untreated. Usage of pharmacologic agents represents one of many therapeutic strategies that can be used to help manage these lesions. Ongoing research into these compounds continues to change our clinical understanding as to which agents most benefit particular patient populations. Indeed, factors such as past personal medical history, lesion location and tolerability of therapy only represent a few considerations that clinicians must account for when prescribing appropriate treatment. This review focuses on specific drugs used in either the prevention or treatment of AKs. Nicotinamide, acitretin and topical 5-fluorouracil (5-FU) continue to be used with fidelity in the chemoprevention of actinic keratosis, although some uncertainty persists in regard to which agents should be used in immunocompetent vs. immunodeficient/immunosuppressed patients. Topical 5-FU, including combination formulations with either calcipotriol or salicylic acid, as well as imiquimod, diclofenac and photodynamic light therapy are all accepted treatment strategies employed to target and eliminate AKs. Five percent of 5-FU is regarded as the most effective therapy in the condition, although the literature has conflictingly shown that lower concentrations of the drug might also be as effective. Topical diclofenac (3%) appears to be less efficacious than 5% 5-FU, 3.75-5% imiquimod and photodynamic light therapy despite its favorable side effect profile. Finally, traditional photodynamic light therapy, while painful, appears to be of higher efficacy in comparison to its more tolerable counterpart, daylight phototherapy.

Efficacy and Safety of Sonic Hedgehog Inhibitors in Basal Cell Carcinomas: An Updated Systematic Review and Meta-analysis (2009-2022)

BACKGROUND

Basal cell carcinoma (BCC) of the skin is the most common form of skin cancer in the United States. In life-threatening, advanced BCC, sonic hedgehog inhibitors (SSHis) remain a pre-eminent treatment option for locally advanced BCC and metastatic BCC.

OBJECTIVE

In this updated systematic review and meta-analysis, we aimed to better characterize the efficacy and safety of SSHis by including final updates from pivotal clinical trials and additional new recent studies.

METHODS

An electronic database search was performed for articles including clinical trials, prospective case series, and retrospective medical record reviews on human subjects. Overall response rates (ORRs) and complete response rates (CRRs) were the primary outcomes. For safety assessment, the prevalence of the following adverse effects was analyzed: muscle spasms, dysgeusia, alopecia, weight loss, fatigue, nausea, myalgias, vomiting, skin squamous cell carcinoma, increased creatine kinase, diarrhea, decreased appetite, and amenorrhea. Analyses were performed using R statistical software. Data were pooled using linear models with fixed effects meta-analysis for primary analyses, along with 95% confidence intervals (CIs) and p-values. Intermolecular differences were calculated using Fisher's exact test.

RESULTS

A total of 22 studies (N = 2384 patients) were included in the meta-analysis: 19 studies assessing both efficacy and safety, 2 studies assessing safety only, and 1 study assessing efficacy only. Overall, the pooled ORR for all patients was 64.9% (95% CI 48.2-81.6%), implicating there is at least a partial response (z = 7.60, p < 0.0001) in most patients receiving SSHis. The ORR for vismodegib was 68.5% and 50.1% for sonidegib. The most common adverse effects for vismodegib and sonidegib were muscle spasms (70.5% and 61.0%, respectively), dysgeusia (58.4% and 48.6%, respectively), and alopecia (59.9% and 51.1%, respectively). Patients were likely to experience weight loss (35.1%, p < 0.0001) from vismodegib. Alternatively, patients taking sonidegib experienced more nausea, diarrhea, increased creatine kinase levels, and decreased appetite compared with those receiving vismodegib.

CONCLUSION

SSHis are an effective treatment for advanced BCC disease. Given the high discontinuation rates, management of patient expectations is warranted for compliance and achieving long-term efficacy. It is essential to stay updated with the latest discoveries on the efficacy and safety of SSHis.

Uveal melanoma incidence trends in Canada: 1992-2010 vs. 2011-2017

Background/aims

Uveal melanoma is the most common type of non-cutaneous melanoma and the most common ocular malignancy in the adult population, especially affecting Caucasians (98% of cases). Despite its low incidence rate, we have noted increasing incidence trends in recent years.

Methods

We analyzed uveal melanoma incidence data using the Canadian Cancer Registry (CCR) for 2011-2017 years. The data was examined using the International Classification of Diseases for Oncology, Third Edition, codes for all uveal melanoma subtypes. The data for 2011-2017 was then compared to previously published work by our research group for uveal melanoma incidence in Canada between 1992 and 2010 using the same methodology.

Results

Between 2011 and 2017, 1,215 patients were diagnosed with uveal melanoma, 49% of whom were females. The percentage distribution of uveal melanoma between the sexes was similar between 1992-2010 and 2011-2017, whereby of the 2,215 diagnoses of uveal melanoma in 1992-2010, 47.9% were females. The change in the incidence rate for this cancer has doubled between 1992-2010 and 2011-2017, from 0.074 to 0.15 cases per million individuals per year. Our study documents that the Canadian 2011-2017 age-standardized incidence rate (ASIR) for uveal melanoma against the World Health Organization (WHO) 2000-2025 world population standard was 5.09 cases per million individuals per year (95% confidence interval, 4.73-5.44), as compared with the 1992-2010 rate of 3.34 cases per million individuals per year (95% confidence interval, CI 3.20 to 3.47).

Conclusion

This work demonstrates an ongoing, steady increase in uveal melanoma incidence in Canada in recent years.

Measuring h-index and scholarly productivity in academic dermatology in Canada

Promotion in academia heavily relies on research productivity. The h-index is a standardized metric used to quantify research productivity at the individual level. We evaluated factors associated with h -index in dermatology across select Canadian academic centers with special focus on sex and academic rank. Medical academic centers throughout Canada with dermatology training programs were included. For each faculty member, we extracted the following data from public sources: sex, graduate degree, academic rank, years since the Fellow of the Royal College of Physicians and Surgeons of Canada (FRCPC) certification or equivalent, recent Canadian Institutes of Health Research (CIHR) funding and H-index (based on Scopus author profile). Log-linear univariate and multivariate regression analyses were performed to evaluate the association between h-index and these factors. An ordinal logistic regression was performed to explore sex differences in academic ranking. Our results showed that out of 300 faculty members across Canada, 155 were females (51.67%) and 145 were male (48.33%). H-index was available for 279 dermatologists. The average h-index was 8.35 (SD 11.53) and the median was 4.00 (1st quartile = 2.00, 3rd quartile = 10.00). Higher h-index was associated with more years since dermatology certification, successive academic rank, graduate degree and recent CIHR funding, but not with sex. In conclusion, h-index was not associated with sex when controlling for potential confounders. These results could reflect recent demographic changes in the field with an increase in newly appointed female dermatologists. Longitudinal assessment of academic productivity in dermatology is needed to assess the impact of continued efforts to promote equal opportunities in the field.

Novel role of long non-coding RNAs in autoimmune cutaneous disease

Systemic autoimmune rheumatic diseases (SARDs) are a heterogeneous group of chronic multisystem inflammatory disorders that are thought to have a complex pathophysiology, which is not yet fully understood. Recently, the role of non-coding RNAs, including long non-coding RNA (lncRNA), has been of particular interest in the pathogenesis of SARDs. We aimed to summarize the potential roles of lncRNA in SARDs affecting the skin including, systemic sclerosis (SSc), dermatomyositis (DM) and cutaneous lupus erythematosus (CLE). We conducted a narrative review summarizing original articles published until July 19, 2021, regarding lncRNA associated with SSc, DM, and CLE. Several lncRNAs were hypothesized to play an important role in disease pathogenesis of SSc, DM and CLE. In SSc, Negative Regulator of IFN Response (NRIR) was thought to modulate Interferon (IFN) response in monocytes, anti-sense gene to X-inactivation specific transcript (TSIX) to regulate increased collagen stability, HOX transcript antisense RNA (HOTAIR) to increase numbers of myofibroblasts, OTUD6B-Anti-Sense RNA 1 to decrease fibroblast apoptosis, ncRNA00201 to regulate pathways in SSc pathogenesis and carcinogenesis, H19X potentiating TGF-β-driven extracellular matrix production, and finally PSMB8-AS1 potentiates IFN response. In DM, linc-DGCR6-1 expression was hypothesized to target the USP18 protein, a type 1 IFN-inducible protein that is considered a key regulator of IFN signaling. Additionally, AL136018.1 is suggested to regulate the expression Cathepsin G, which increases the permeability of vascular endothelial cells and the chemotaxis of inflammatory cells in peripheral blood and muscle tissue in DM. Lastly, lnc-MIPOL1-6 and lnc-DDX47-3 in discoid CLE were thought to be associated with the expression of chemokines, which are significant in Th1 mediated disease. In this review, we summarize the key lncRNAs that may drive pathogenesis of these connective tissue diseases and could potentially serve as therapeutic targets in the future.

Informing a Canadian Skin Science Trainee Program Based on the State of Trainee Programs Offered by International Academic Societies

BACKGROUND

For dermatology to effectively address the ever-growing medical needs, longstanding communication barriers across investigators working in different research pillars and practicing clinicians must be improved. To address this problem, trainee-specific programs are now evolving to align their educational landscape across basic science, translational and clinical research programs.

OBJECTIVES

To establish a Skin Investigation Network of Canada (SkIN Canada) training roadmap for the career and skill development of future clinicians, clinican scientists and basic scientists in Canada. This Working Group aims to strengthen and harmonize collaborations and capacity across the skin research community.

METHODS

The Working Group conducted a search of established international academic societies which offered trainee programs with mandates similar to SkIN Canada. Societies' program items and meetings were evaluated by use of an interview survey and/or the collection of publicly available data. Program logistics, objectives and feedback were assessed for commonalities and factors reported or determined to improve trainee experience.

RESULTS

Through the various factors explored, the Working Group discovered the need for increasing program accessibility, creating opportunities for soft skill development, emphasizing the importance of current challenges, collecting and responding to feedback, and improving knowledge sharing to bridge pillars of skin research.

CONCLUSIONS

Although improvements have been made to trainee education in recent years, a plurality of approaches exist and many of the underlying roadblocks remain unresolved. To establish fundamental clinician-basic scientist collaboration and training efforts, this Working Group highlights important factors to include and consider in building a trainee program and emphasizes the importance of trainee education.

Utilization of the Psoriasis Epidemiology Screening Tool (PEST): A Risk Stratification Strategy for Early Referral of Psoriatic Arthritis Patients to Minimize Irreversible Erosive Joint Damage

Psoriatic arthritis (PsA) can affect a diverse range of anatomical sites and its heterogeneous presentation contributes to misdiagnosis and delayed treatment with conventional and biologic disease-modifying antirheumatic drugs (DMARDs). Up to 15% of psoriasis (PsO) patients affected by PsA remain undiagnosed. Early detection and referral to a rheumatologist are crucial to optimize care and minimize irreversible erosive joint damage. To improve the rheumatology referral process, the authors propose a risk stratification tool to identify and triage patients with possible psoriatic arthritis. With the aim of ultimately assisting in early treatment initiation, this risk stratification algorithm can be used in both dermatology and primary care clinics. It is based on the Psoriasis Epidemiology Screening Tool (PEST) combined with the ClASsification criteria for Psoriatic Arthritis (CASPAR). This article intends to provide a rationale for further prospective studies whose objective would be to validate this screening algorithm.

Selective TYK2 Inhibition in the Treatment of Moderate to Severe Chronic Plaque Psoriasis

Moderate to severe chronic plaque psoriasis may be difficult to control using current therapies, which has led to development of a novel class of therapy, selective tyrosine kinase 2 (TYK2) inhibitors, to address this unmet need. Oral deucravacitinib is a first-inclass selective TYK2 inhibitor, which has shown efficacy in moderate to severe chronic plaque psoriasis from two phase III pivotal trials (POETYK PSO-1 and PSO-2), whereby response rates were significantly higher with deucravacitinib vs. placebo or apremilast for Psoriasis Area Severity Index (PASI) 75 and static Physician's Global Assessment (sPGA) 0/1. Deucravacitinib was generally well tolerated and safe compared to placebo and apremilast. Although deucravacitinib is a type of Janus kinase (JAK) inhibitor, it only blocks specific cytokine-driven responses, potentially reducing off-target effects more commonly associated with other JAK inhibitors on the market. Incidence rates of serious adverse events, such as serious infections, malignancies, thrombosis, cardiovascular events, creatinine kinase elevation, hematologic changes, and lipid profile abnormalities were absent or low.

The Use of Retinoids for the Prevention and Treatment of Skin Cancers: An Updated Review

Retinoids are natural and synthetic vitamin A derivatives that are effective for the prevention and the treatment of non-melanoma skin cancers (NMSC). NMSCs constitute a heterogenous group of non-melanocyte-derived skin cancers that impose substantial burdens on patients and healthcare systems. They include entities such as basal cell carcinoma and cutaneous squamous cell carcinoma (collectively called keratinocyte carcinomas), cutaneous lymphomas and Kaposi’s sarcoma among others. The retinoid signaling pathway plays influential roles in skin physiology and pathology. These compounds regulate diverse biological processes within the skin, including proliferation, differentiation, angiogenesis and immune regulation. Collectively, retinoids can suppress skin carcinogenesis. Both topical and systemic retinoids have been investigated in clinical trials as NMSC prophylactics and treatments. Desirable efficacy and tolerability in clinical trials have prompted health regulatory bodies to approve the use of retinoids for NMSC management. Acceptable off-label uses of these compounds as drugs for skin cancers are also described. This review is a comprehensive outline on the biochemistry of retinoids, their activities in the skin, their effects on cancer cells and their adoption in clinical practice.

Exposure to silica and systemic sclerosis: A retrospective cohort study based on the Canadian Scleroderma Research Group

Introduction

Systemic sclerosis (SSc) is thought to be induced by an environmental trigger in genetically predisposed individuals. This study assessed the demographic and clinical characteristics and disease severity of silica exposed SSc patients.

Methods

Data was obtained from the Canadian Scleroderma Research Group (CSRG) cohort, containing 1,439 patients (2004–2019). Univariate and multivariate logistic regression analyses were performed, to determine the phenotype and severity of silica-exposed SSc patients. Mortality was assessed using Cox Survival Regression and Kaplan-Meier analyses.

Results

Among 1,439 patients (86.7% females), 95 patients reported exposure to silica. Those exposed were younger, of male sex and with more severe disease. Sex differences were observed where male patients exposed to silica were more likely to be Caucasian and smokers whereas female patients were younger at SSc diagnosis compared to unexposed. Multivariate regression, controlled for multiple confounders, showed that silica exposure was associated with a younger age at diagnosis and worse disease severity and mortality.

Conclusion

Exposure to silica was reported in ∼7% of CSRG cohort and ∼20% of male patients and was associated with a worse prognosis in terms of age of diagnosis, organ involvement and mortality. Hence, screening for silica exposure among higher risk individuals may be beneficial and these patients may require closer monitoring for systemic disease.

Risk factors and communities disproportionately affected by cervical cancer in the Russian Federation: A national population-based study

Background

Cervical cancer is one of the leading causes of cancer in women of childbearing age worldwide. A substantial fraction of cervical cancer is associated with Human Papilloma Virus (HPV) infection and is preventable through vaccination and screening. The aim of the study is to describe geographic and epidemiologic trends in incidence and mortality of cervical cancer in Russia during 2007–2018.

Methods

Publicly accessible data from the P.A. Herzen Moscow Oncology Research Institute and the Ministry of Health of Russian Federation for 2007–2018 was used for this study. Cervical cancer incidence and mortality rates were analyzed using descriptive statistics and results were mapped to determine the geographic distribution. Potential contributing risk factors in the population were studied using univariate and multivariate Poisson regression analyses.

Findings

A total of 187,013 patients were diagnosed with cervical cancer in Russia between 2007 and 2018. The average age-standardized incidence (ASIR) and mortality rates (ASMR) were 15.70/100,000 and 5.76/100,000 females, respectively, with a 27% increase in the incidence observed between 2007 and 2018. The highest ASIR was observed in the Far Eastern Federal District and the lowest in the Central Federal District. Multivariate model for cervical cancer ASIR showed that daily smoking (p = 0·0003) and syphilis (p = 0.003) were significantly associated with cervical cancer incidence.

Interpretation

The incidence of cervical cancer in Russia is rising at a significant pace. This trend can in part be attributed to a lack of nationwide cervical cancer screening . The presented results are valuable for informing public health policy on HPV vaccinations, smoking prevention and cervical cancer screening as urgent interventions are needed to combat a troubling trend.

Funding

This work was supported by the Cancer Research Society (CRS)-Canadian Institutes for Health Research (CIHR) Partnership Grant #25343 to Dr. Litvinov. Canadian Dermatology Foundation research grant to Dr. Litvinov, and by the Fonds de la recherche du Québec – Santé to Dr. Sasseville (#22648) and to Dr. Litvinov (#34753 and #36769). This research was further supported by the CIHR Catalyst Grant #428712 to Dr. Litvinov.

Extracorporeal Photopheresis and Its Use in Clinical Dermatology in Canada

Extracorporeal photopheresis (ECP) is an immunomodulatory therapy that has been used for over 35 years to treat numerous conditions. ECP was initially approved by the US FDA in 1988 for the treatment of Sézary syndrome, a leukemic form of cutaneous T-cell lymphoma (CTCL). Although CTCL remains the only FDA-approved indication, ECP has since been used off-label for numerous other conditions, including graft-versus-host disease (GvHD), systemic sclerosis, autoimmune bullous dermatoses, Crohn's disease, and prevention of solid organ transplant rejection. In Canada, ECP is mainly used to treat CTCL, acute and chronic GvHD, and in some instances systemic sclerosis. Herein, we review the current concepts regarding ECP mechanism of action, treatment considerations and protocols, and efficacy.

In silico Identification of Immune Cell-Types and Pathways Involved in Chronic Spontaneous Urticaria

Background

The immunopathogenesis of chronic spontaneous urticaria (CSU) is poorly understood, but recent research suggests that patients can be divided into autoallergic and autoimmune subtypes. Given that not all patients can be controlled with current treatment regimens, including anti-IgE monoclonal antibodies, a better understanding of the immune pathways involved in CSU may enable the repurposing of monoclonal antibodies used for other dermatologic diseases (e.g., Th2 and Th17 inhibitors). Therefore, we investigated the implicated immune cells and pathways by reanalyzing publicly available transcriptomic data.

Methods

Microarray data of CSU and healthy control (HC) skin and blood were obtained from the Gene Expression Omnibus (GSE72542, GSE57178). Differentially expressed genes were defined as a false discovery rate <0.05 and a |log₂ fold change| ≥1. Pathway analyses were conducted using ToppGene and KEGG. Cell-type enrichment was determined by CIBERSORT and xCell and was correlated with clinical characteristics.

Results

Th2 (IL-4/13 signaling) and Th17-related (IL-17/23 signaling) pathways were upregulated in lesional compared to non-lesional and HC samples. In non-lesional versus lesional samples, CIBERSORT analysis revealed increased regulatory T-cells (Treg) and resting mast cells. xCell analysis established that Th1 and Th2 scores were not significantly different between lesional and HC samples. However, Th2 scores in both lesional and non-lesional samples correlated positively with disease severity. Few differentially expressed genes and pathways were identified between CSU and HC blood samples.

Conclusion

Our results support the involvement of Th2 and Th17-related genes and pathways in CSU. Th2 scores associate with disease severity, which indicates the clinical relevance of these findings. Increased resting mast cell and Treg scores in non-lesional samples may suggest local suppression of wheal formation. Moreover, disease activity seemed to be restricted to the skin as there were limited findings from blood. Larger studies using next-generation sequencing will be helpful to confirm these results.

Abstract 98: The role of HORMAD1 in transformation of keratinocytes following vemurafenib treatment

BRAF inhibitor (BRAFi) therapies are highly effective treatments for metastatic melanoma. However, BRAFi monotherapies are associated with a significant risk of squamous cell carcinoma (SCC) development in melanoma patients. Consequently, BRAF inhibition results in an unanticipated activation of the MAPK pathway in surrounding cells that harbour wildtype BRAF. Fortunately, a combination approach with both a BRAFi and the selective MAPK inhibitor (MEKi), trametinib, attenuates BRAFi-induced risk of SCCs. Despite the fact that this combination therapy is widely used in clinical practice, the mechanisms associated with SCC induction and why this effect is attenuated with a MEK inhibitor remain poorly understood. HORMAD1, a meiosis specific gene, has been shown to have an impact on genomic instability and proliferation in the development of SCCs. Moreover, recent work in our lab has demonstrated that the MAPK pathway regulates HORMAD1 expression in SCC cell lines. Therefore, we sought to investigate a potential role of HORMAD1 in the risk and development of SCCs as a mechanism of BRAFi that is attenuated with the co-administration of the MEKi, trametinib. Using the BRAFi, vemurafenib, we inhibited the kinase activity of activated BRAF (V600E) and the MEKi, trametinib to evaluate the expression of HORMAD1 in melanoma and normal keratinocyte cell lines. To determine the effects of these two inhibitors, a cell proliferation assay was conducted followed by the evaluation of various components of cell cycle regulation and genomic instability. We found that HORMAD1 protein expression levels increased following treatment with the BRAFi, vemurafenib, in the normal keratinocyte cell line, HaCaT, but not in the melanoma cell line, A375. In contrast, HORMAD1 expression decreased following treatment with the MEKi, trametinib in both HaCaT and A375. Cell proliferation assays depict a vulnerability to both vemurafenib and trametinib in both normal and melanoma cell lines, however, HaCaT cells appear to be more susceptible to increased levels of genomic instability following treatment with vemurafenib when compared to A375. Our results suggest that HORMAD1 likely plays a key role in the development of SCCs by increasing genomic instability and proliferation in normal keratinocytes following BRAFi monotreatment. The increased risk of SCC formation is attenuated by dampening HORMAD1 levels with the co-administration of the MEKi, trametinib.

Citation Format: Jennifer Gantchev, Amelia Martinez Villarreal, Brandon Ramchatesingh, Ivan V. Litvinov. The role of HORMAD1 in transformation of keratinocytes following vemurafenib treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 98.

Analysis of Geographic and Environmental Factors and Their Association with Cutaneous Melanoma Incidence in Canada

BACKGROUND

Over 90% of skin cancers including cutaneous melanoma (CM) are related directly to sun exposure. Despite extensive knowledge on ultraviolet radiation's (UVR) detrimental impact, many still fail to implement sun protection/sun avoidance. Human behavior, attitudes, and cultural norms of individuals and communities heavily depend on the surrounding climate/environment. In many instances, the climate shapes the culture/norms of the society. Canada has vast geographic/environmental differences.

METHODS

In the current ecological study, we sought to examine the relationship between various geographic and environmental factors and the distribution of CM incidence by Forward Sortation Area (FSA) postal code across Canada. CM incidence data were extracted from the Canadian Cancer Registry, while environmental data were extracted from the Canadian Urban Environmental Health Research Consortium (greenspace, as measured by the normalized difference vegetation index; annual highest temperature; absolute number and average length of yearly heat events; annual total precipitation [rain and snow]; absolute number and average length of events with precipitation [rain and snow]; and summer UVR index). The above geographic/environmental data by FSA were correlated with the respective CM incidence employing negative binomial regression model.

RESULTS

Our analysis highlights that increases in annual average temperature, summer UVR, and greenspace were associated with higher expected incidence of CM cases, while higher number of annual heat events together with highest annual temperature and higher average number of annual rain events were associated with a decrease in CM incidence rate. This study also highlights regional variation in environmental CM risk factors in Canada.

CONCLUSIONS

This national population-based study presents clinically relevant conclusions on weather/geographic variations associated with CM incidence in Canada and will help refine targeted CM prevention campaigns by understanding unique weather/geographic variations in high-risk regions.

Population-Based Study Detailing Cutaneous Melanoma Incidence and Mortality Trends in Canada

Background

Cutaneous melanoma (CM) is one of the most fatal types of skin cancer. Alarmingly, increases in incidence and mortality were noted globally for this malignancy, despite increase in understanding of melanoma pathogenesis and enhanced prevention efforts.

Methods

Data was extracted for CM patients for provinces and territories (except Quebec) using two independent, population-based registries. Analysis was performed using both clinical and pathological characteristics: tumor morphologic classification, age, sex, anatomic site affected and place of residence. Mortality trends were assessed over a 7-year period. Results were compared to prior findings for 1992-2010.

Results

During 2011-2017 39,610 patients were diagnosed with CM, with 5,890 reported deaths. National crude CM incidence was 20.75 (age-standardized incidence: 14.12) cases per 100,000 individuals per year. Females accounted for 45.8% of cases and 37.1% of deaths. While CM incidence rates continue to increase in both sexes, since 2013 the CM mortality is declining. We observed important differences across the provinces/territories, where Nova Scotia, Prince Edward Island, southern Ontario/British Columbia and certain coastal communities of New Brunswick demonstrated higher CM incidence and mortality rates. The observed incidence and mortality trends for 2011-2017 validate and extend earlier observations from 1992 to 2010 for CM.

Conclusion

This population-based study highlights that while melanoma's incidence is increasing in Canada, mortality rates are for the first time decreasing since 2013. We detail regional distribution of this cancer highlighting communities in southern/coastal areas, as being most at risk as well as the latest trends of melanoma incidence by age, sex and anatomic site. In males, melanoma is more common on the head/trunk, while in females on the extremities. Notably, Acral Lentiginous Melanoma was the only CM subtype that was more common in females, which primarily affects hands and feet.

Sex Differences in the Patterns of Systemic Agent use Among Patients With Psoriasis: A Retrospective Cohort Study in Quebec, Canada

Background: Sex differences exist in psoriasis manifestation and expectations from treatment with systemic agents, including, conventional systemic agents (CSA) and tumor necrosis factor inhibitors or ustekinumab (TNFi/UST). However, sex differences in patterns of systemic agent use, such as CSA discontinuation and switch from CSA to TNFi/UST have not been examined.

Objectives: To assess sex differences in patterns of CSA use and identify factors associated with switch to (or add) a TNFi/UST and those associated with CSA discontinuation.

Methods: We conducted a retrospective cohort study using the Quebec health administrative databases. We included patients with psoriasis initiating a CSA in 2002–2015. We excluded patients with a psoriasis diagnosis in the 3 years prior to the first diagnosis date between 2002 and 2015, and those with a systemic agent dispensation in the year prior to that date. We used Cox regression models with the Least Absolute Shrinkage and Selection Operator method to identify factors associated with Switch/add TNFi/UST, and those associated with CSA discontinuation. Separate analyses were performed for male and female patients.

Results: We included 1,644 patients (55.7% females, mean age 60.3 years), among whom 60.4% discontinued their CSA and 7.4%, switched/added TNFi/UST (3.4% switched and 4.0% added) within a median of 0.78 years of follow-up. Among male and female patients, rates of Switch/add TNFi/UST per 1,000 person-year were 49.1 and 41.0 and rates of CSA discontinuation were 381.2 and 352.8. Clinical obesity in male patients (HR 3.53, 95% CI 1.20–10.35), and adjustment/somatoform/dissociative disorders (HR 3.17, 95% CI 1.28–7.85) and use of nonsteroidal anti-inflammatory drugs (HR 2.70, 95% CI 1.56–4.70) in female patients were associated with Switch/add TNFi/UST. Male patients followed by a rheumatologist (HR 0.66, 95% CI 0.46–0.94) and those with a prior hospitalization (HR 0.70, 95% CI 0.57–0.87) were at lower risk of CSA discontinuation, while those initiated on acitretin (vs methotrexate) were at higher risk to discontinue their CSA (HR 1.61, 95% CI 1.30–2.01). Female patients with rheumatoid arthritis comorbidity (HR 0.69, 95% CI 0.51–0.93), those with a dispensed lipid-lowering agent (HR 0.72, 95% CI 0.59–0.88) and hypoglycemic agent (HR 0.75, 95% CI 0.57–0.98) and those initiated on methotrexate (vs all other CSAs) were less likely to discontinue their CSA. Male and female patients entering the cohort between 2011 and 2015 were at reduced risk of CSA discontinuation compared to those entering the cohort before 2011.

Conclusion: Most male and female patients discontinued their CSA within 1 year of follow-up. Our study highlighted sex differences in patients’ characteristics associated with switch/add a TNFi/UST and CSA discontinuation; treatment switch and discontinuation may be indications of treatment failure in most patients.

Plerixafor on a WHIM - Promise or Fantasy of a New CXCR4 Inhibitor for This Rare, but Important Syndrome?

Warts, Hypogammaglobulinemia, Infections and Myelokathexis (WHIM) is a primary immunodeficiency syndrome. Patients with WHIM syndrome are more susceptible to human papillomavirus (HPV) infections and commonly present to a dermatologist with recalcitrant to treatment warts. Other cardinal features of WHIM syndrome include recurrent sinopulmonary bacterial infections, neutropenia/lymphopenia, low levels of immunoglobulins (IgG, IgA, IgM) and myelokathexis. Research demonstrated that truncating gain-of-function mutations of the C-X-C chemokine receptor type 4 gene (CXCR4) are responsible for this disease. Plerixafor, a specific small molecule antagonist of CXCR4, is currently used for peripheral blood hematopoietic stem cell (HSC) mobilization in stem cell transplant recipients. It has recently shown promise for the treatment of WHIM syndrome in phase I/II clinical trials. In this paper we review the emerging patient clinical data for this medication and highlight the role of CXCR4 in other important skin diseases including keratinocyte carcinomas, psoriasis and cutaneous T-cell lymphoma.