The pathogenesis of cutaneous squamous cell carcinoma in organ transplant recipients

Cumulative incidence and risk factors for cutaneous squamous cell carcinoma metastases in organ transplant recipients: The Skin Care in Organ Transplant Patients in Europe-International Transplant Skin Cancer Collaborative metastases study, a prospective multicenter study

INTRODUCTION

Solid organ transplant recipients (SOTRs) are believed to have an increased risk of metastatic cutaneous squamous cell carcinoma (cSCC), but reliable data are lacking regarding the precise incidence and associated risk factors.

METHODS

In a prospective cohort study, including 19 specialist dermatology outpatient clinics in 15 countries, patient and tumor characteristics were collected using standardized questionnaires when SOTRs presented with a new cSCC. After a minimum of 2 years of follow-up, relevant data for all SOTRs were collected. Cumulative incidence of metastases was calculated by the Aalen-Johansen estimator. Fine and Gray models were used to assess multiple risk factors for metastases.

RESULTS

Of 514 SOTRs who presented with 623 primary cSCCs, metastases developed in 37 with a 2-year patient-based cumulative incidence of 6.2%. Risk factors for metastases included location in the head and neck area, local recurrence, size > 2 cm, clinical ulceration, poor differentiation grade, perineural invasion, and deep invasion. A high-stage tumor that is also ulcerated showed the highest risk of metastasis, with a 2-year cumulative incidence of 46.2% (31.9%-68.4%).

CONCLUSIONS

SOTRs have a high risk of cSCC metastases and well-established clinical and histologic risk factors have been confirmed. High-stage, ulcerated cSCCs have the highest risk of metastasis.

Mutational Profiles of Cutaneous Squamous Cell Carcinomas with Different Patterns of Clinical Aggression from Head and Neck Regions

Cutaneous squamous cell carcinoma is a prevalent malignancy with a rising incidence and a notably high mutational load. Exploring the genetic nuances of cSCC and investigating molecular approaches stands as a potential avenue for improving outcomes in high-risk patients. This retrospective case-control study involved two cohorts, one of 14 patients (the "discovery cohort") and the other of 12 patients (the "validation cohort"), with cSCC located in the head/neck anatomical region and diagnosed at the pT2 stage. Overall, cases developed early local relapses of the disease, whereas controls never relapsed during the entire follow-up period. A next-generation sequencing (NGS) approach conducted on histological samples revealed that TP53 and CDKN2A were the most frequently mutated genes in our series. No specific mutations were identified as potential prognostic or therapeutic targets. Controls exhibited a tendency toward a higher mutational rate compared to cases. It is possible that an increased number of mutations could prompt the cSCC to expose more antigens, becoming more immunogenic and facilitating recognition by the immune system. This could enhance and sustain the immunological response, potentially preventing future recurrences.

Detection of α-papillomaviruses in extragenital cutaneous squamous cell carcinomas

Previous studies have demonstrated that human papillomaviruses (HPVs) of the beta genus can contribute to the onset of cutaneous carcinomas in organ transplant recipients. In contrast, there are limited data related to the oncogenicity of alpha (α)-HPVs in the skin. Herein, we explore the characteristics of three cutaneous squamous cell carcinomas presenting α-HPV infection occurring in patients with HIV, in order to determine the role of α-HPV in these skin cancers.

Frequency of skin diseases in renal transplant recipients and patients with chronic kidney disease in a tertiary center: a cross-sectional study

BACKGROUND

The prevalence of chronic kidney disease (CKD) has increased in the recent decades, along with the number of patients in the terminal stages of this disease, requiring transplantation. Some skin disorders are more frequent in patients with CKD and in renal transplant recipients (RTR).

OBJECTIVES

To evaluate the frequency of skin diseases in RTR and patients with CKD receiving conservative treatment.

DESIGN AND SETTING

This observational cross-sectional study recruited consecutive patients with CKD and RTR from a nephrology clinic at a teaching hospital in Brazil between 2015 and 2020.

METHODS

Quantitative, descriptive, and analytical approaches were used. The sample was selected based on convenience sampling. Data were collected from dermatological visits and participants' medical records.

RESULTS

Overall, 308 participants were included: 206 RTR (66.9%, median age: 48 years, interquartile range [IQR] 38.0-56.0, 63.6% men) and 102 patients with CKD (33.1%, median age: 61.0 years, IQR 50.0-71.2, 48% men). The frequency of infectious skin diseases (39.3% vs. 21.6% P = 0.002) were higher in RTR than in patients with CKD. Neoplastic skin lesions were present in nine (4.4%) RTR and in only one (1.0%) patient with CKD. Among the RTR, the ratio of basal cell carcinoma to squamous cell carcinoma was 2:1.

CONCLUSIONS

This study revealed that an increased frequency of infectious skin diseases may be expected in patients who have undergone kidney transplantation. Among skin cancers, BCC is more frequently observed in RTR, especially in those using azathioprine.

Skin and gut microbial associations with squamous cell carcinoma in solid organ transplant recipients

Solid organ transplant recipients (SOTRs) are burdened with a significantly higher risk of squamous cell carcinoma (SCC) compared to the general population. Accumulating evidence suggests the potential influence of microbial dysbiosis on transplant outcomes. Based on these observations, we sought to identify differences in the cutaneous and gut microbiomes of SOTRs with and without a history of SCC. This case-control study collected and analyzed non-lesional skin and fecal samples of 20 SOTRs > 18 years old with either ≥ 4 diagnoses of SCC since most recent transplant (n = 10) or 0 diagnoses of SCC (n = 10). The skin and gut microbiomes were investigated with Next-Generation Sequencing, and analysis of variance (ANOVA) followed by Tukey pairwise comparison procedure was used to test for differences in taxonomic relative abundances and microbial diversity indices between the two cohorts. Analyses of the skin microbiome showed increased bacterial and reduced fungal diversity in SOTRs with a history of SCC compared to SOTRs without a history of SCC (bacterial median Shannon diversity index (SDI) = 3.636 and 3.154, p < 0.05; fungal SDI = 4.474 and 6.174, p < 0.05, respectively). Analyses of the gut microbiome showed reduced bacterial and fungal diversity in the SCC history cohort compared to the SCC history-negative cohort (bacterial SDI = 2.620 and 3.300, p < 0.05; fungal SDI = 3.490 and 3.812, p < 0.05, respectively). The results of this pilot study thus show a trend toward the bacterial and fungal communities of the gut and skin being distinct in SOTRs with a history of SCC compared to SOTRs without a history of SCC. It furthermore demonstrates the potential for microbial markers to be used in the prognostication of squamous cell carcinoma risk in solid organ transplant recipients.

Management of Cutaneous Head and Neck Squamous and Basal Cell Carcinomas for Immunocompromised Patients

The incidence of non-melanoma skin cancer (NMSC) continues to rise, and more than one million cases are diagnosed in the United States each year. The increase in prevalence has been attributed to increased lifespan and improvements in survival for conditions that increase the risk of these malignancies. Patients who are immunocompromised have a higher risk of developing NMSC compared to the general population. In immunosuppressed patients, a combination of prevention, frequent surveillance, and early intervention are necessary to reduce morbidity and mortality. In this review, we collate and summarize current knowledge regarding pathogenesis of head and neck cutaneous SCC and BCC within immunocompromised patients, examine the potential role of the immune response in disease progression, and detail the role of novel immunotherapies in this subset of patients.

Association of Nonmelanoma Skin Cancers, Melanoma, and Merkel Cell Carcinoma with Dermatologic Medications: A Case-Control Pharmacovigilance Study of the FDA Adverse Events Reporting System

BACKGROUND

Medications used in the treatment of dermatologic conditions have been associated with squamous cell carcinoma (SCC), basal cell carcinoma (BCC), melanoma, and Merkel cell carcinoma (MCC).

OBJECTIVE

The objective of the study was to examine the relationship between systemic dermatologic medications and skin cancer in the FDA Adverse Event Reporting System (FAERS).

METHODS

Case-control analyses were performed in FAERS from 1968 to 2021 to examine the reporting odds ratios (RORs) for SCC, BCC, melanoma, and MCC.

RESULTS

The oral immunosuppressants were all associated with increased ROR of SCC, BCC, melanoma, and MCC. Azathioprine had the highest ROR for SCC (34.13, 95% CI 29.07-40.08), BCC (21.15, 95% CI 20.63-25.98), and MCC (44.76, 95% CI 31.52-63.55), while quinacrine and guselkumab had the highest ROR for melanoma (13.14, 95% CI 1.84-93.89 vs. 12.73, 95% CI 10.60-15.30, respectively). The TNF-α inhibitors were associated with an increased ROR for all skin cancers investigated.

CONCLUSIONS

The oral immunosuppressants and many biologic medications were associated with an increased ROR of skin cancers including TNF-α inhibitors (etanercept, adalimumab, infliximab), IL-23 or IL-12/23 inhibitors (ustekinumab, risankizumab), and the CD-20 inhibitor rituximab but not dupilumab or IL-17 inhibitors.

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.

Targeting Staphylococcus aureus dominated skin dysbiosis in actinic keratosis to prevent the onset of cutaneous squamous cell carcinoma: Outlook for future therapies?

Cutaneous squamous cell carcinoma (cSCC) and its premalignant precursor, actinic keratosis (AK), present a global health burden that is continuously increasing despite extensive efforts to promote sun safety. Chronic UV exposure is a recognized risk factor for the development of AK and cSCC. However, increasing evidence suggests that AK and cSCC is also associated with skin microbiome dysbiosis and, in particular, an overabundance of the bacterium Staphylococcus aureus (S. aureus). Studies have shown that S. aureus-derived toxins can contribute to DNA damage and lead to chronic upregulation of proinflammatory cytokines that may affect carcinogenesis. Eradication of S. aureus from AK lesions and restoration of a healthy microbiome may therefore represent a therapeutic opportunity to alter disease progression. Whilst antibiotics can reduce the S. aureus load, antibiotic resistant S. aureus pose an increasing global public health threat. The use of specific topically delivered probiotics has been used experimentally in other skin conditions to restore eubiosis, and could therefore also present a non-invasive treatment approach to decrease S. aureus colonization and restore a healthy skin microbiome on AK lesions. This article reviews mechanisms by which S. aureus may contribute to cutaneous carcinogenesis, and discusses hypotheses and theories that explore the therapeutic potential of specific bacterial species which compete with S. aureus in an attempt to restore microbial eubiosis in skin.

Cumulative UV Exposure or a Modified SCINEXA™-Skin Aging Score Do Not Play a Substantial Role in Predicting the Risk of Developing Keratinocyte Cancers after Solid Organ Transplantation-A Case Control Study

The risk of keratinocyte cancer is determined by intrinsic and extrinsic factors, which also influence skin aging. Few studies have linked skin aging and UV exposure with the incidence of non-melanoma skin cancer (NMSC). We evaluated signs of actinic skin damage and aging, individual UV burden, and melanocortin-1 receptor (MC1R) variants. A total of 194 organ transplant recipients (OTR) who suffered from NMSC were compared to 194 tumor-free controls matched for gender, age, type of transplanted organ, post-transplantation (TX) period, and immunosuppressive therapy. Compared with the cases, the controls scored higher in all skin aging scores and there were no differences in UV burden except for intentional whole-body UV exposure for specific UV scenarios and periods of life in favor of cases. The number of NMSCs correlated with all types of skin aging scores, the extent of intentional sun exposure, older age, longer post-TX period, shorter interval from TX to first NMSC, and specific MC1R risk groups. Multivariable models revealed a 7.5-fold risk of developing NMSC in individuals with actinic keratosis; 4.1- or 3.6-fold in those with green or blue eyes, respectively; and a 1.9-fold increased risk in the MC1R medium- + high-risk group. In the absence of skin aging contributing to NMSC development, certain MC1R risk types may identify OTR at risk for high tumor burden.

The role of HPV in keratinocyte skin cancer development: A systematic review

Keratinocyte skin cancers are the most frequent malignancy, accounting for approximately 30% of all cancers. Although beta genus HPV are the main etiologic agents for squamous cell carcinoma development in patients with epidermodysplasia verruciformis and organ transplant recipients, their role in non-melanoma skin cancer (NMSC) progression in the general population remains controversial. The aim of our review is to summarize current scientific data and to systematically analyse evidence regarding the role of HPV in keratinocyte skin cancers. A total of 2284 patients were included, of which 724 with actinic keratoses, 290 with Bowen's disease, 949 with cutaneous squamous cell carcinomas and 321 with keratoacanthomas. In the case of actinic keratoses, the majority were positive for beta (n = 372, 58.49%) and gamma HPV (n = 256, 40.25%) and only a few (n = 6, 0.94%) were positive for alpha subtypes. Similarly, most of the cutaneous squamous cell carcinomas were positive for beta (n = 248, 55.98%) and gamma HPV (n = 172, 33.82%) and 23 cases (2.42%) were positive for alpha subtypes. Bowen's disease lesions were mostly positive for beta (n = 43, 55.84%) and alpha HPV (n = 30, 38.96%), in contrast to the gamma genus (n = 4, 5.19%). Keratoacanthomas showed a high distribution among beta genus (n = 79, 50.31%) and an equal proportion between alpha (n = 39, 24.84%) and gamma (n = 39, 24.84%) genera. Studies published so far identifying HPV in keratinocyte skin cancers reflect the difference in detection methods rather than a type-specific tendency towards either actinic keratoses, Bowen's disease, squamous cell carcinoma or keratoacanthoma. On the other hand, recent evidence regarding the role of HPV vaccination in patients with non-melanoma skin cancer brings into perspective the idea of a beta-HPV vaccine or a combined alpha and beta-HPV vaccine that could be used as an adjuvant treatment measure in patients with recalcitrant non-melanoma skin cancer.

N6-methyladenosine functions and its role in skin cancer

N6-methyladenosine (m6A) methylation is the most abundant mammalian mRNA modification. m6A regulates RNA processing, splicing, nucleation, translation and stability by transferring, removing and recognizing m6A methylation sites, which are critical for cancer initiation, progression, metabolism and metastasis. m6A is involved in pathophysiological tumour development by altering m6A modification and expression levels in tumour oncogenes and suppressor genes. Skin cancers are by far the most common malignancies in humans, with well over a million cases diagnosed each year. Skin cancers are grouped into two main categories: melanoma and non-melanoma skin cancers (NMSC), based on cell origin and clinical behaviour. In this review, we summarize m6A methylation functions in different skin cancers, and discuss how m6A methylation is involved in disease development and progression. Moreover, we review potential prognostic biomarkers and molecular targets for early skin cancer diagnosis and treatment.

Molecular Skin Cancer Diagnosis: Promise and Limitations

Skin cancer is a significant and increasing global health burden. Although the current diagnostic workflow is robust and able to provide clinically actionable results, it is subject to notable limitations. The training and expertise required for accurate diagnoses using conventional skin cancer diagnostics are significant, and patient access to this workflow can be limited by geographic location or unforeseen events, such as coronavirus disease 2019 (COVID-19). Molecular biomarkers have transformed diagnostics and treatment delivery in oncology. With rapid advancements in molecular biology techniques, understanding of the underlying molecular mechanism of cancer pathologies has deepened, yielding biomarkers that can be used to monitor the course of malignant diseases. Herein, commercially available, clinically validated, and emerging skin cancer molecular biomarkers are reviewed. The qualities of an ideal molecular biomarker are defined. The potential benefits and limitations of applying molecular biomarker testing over the course of skin cancer from susceptibility to treatment are explored, with a view to outlining a future model of molecular biomarker skin cancer diagnostics.

Risk of skin cancer in kidney, liver and heart recipients: A nationwide population-based study in Taiwan

Background

Previous population-based studies in western countries had revealed increased skin cancer risk among transplant recipients compared to the general population. However, population-based studies in Asia on skin cancer among recipients of different transplanted organs were lacking in the literature.

Aims

This study aims to estimate skin cancer risk among recipients in Taiwan, examine the association between each specific type of skin cancer and each type of transplanted organ, and compare skin cancer risk between different immunosuppressive regimens.

Methods

This population-based retrospective cohort study identified 7550 patients with heart, lung, kidney or liver transplantation and 30,200 controls matched for gender, age and comorbidity index from the National Health Insurance Research Database in Taiwan between 2000 and 2015. Using multivariable Cox proportional hazard models, we estimated the hazard ratios and 95% confidence intervals for the correlation of skin cancer with organ transplantation as well as immunosuppressive regimen.

Results

Organ transplant recipients in Taiwan had an increased risk of skin cancer with adjusted hazard ratios of 4.327 (95% confidence intervals 2.740-6.837, P < 0.001), with the greatest risk, observed among heart recipients (adjusted hazard ratios 6.348, 95% confidence intervals 3.080-13.088, P < 0.001). The risk of non-melanoma skin cancer and melanoma was 4.473 (95% confidence intervals 2.568-7.783, P < 0.001) and 3.324 (95% confidence intervals 1.300-8.172, P < 0.001), respectively. When comparing immunosuppressants, those with calcineurin inhibitors carried the highest risk of skin cancer (adjusted hazard ratios 4.789, 95% confidence intervals 3.033-7.569, P < 0.001), followed by those with antimetabolites (adjusted hazard ratios 4.771, 95% confidence intervals 3.025-7.541, P < 0.001).

Limitations

We could not evaluate confounding behavioural risk factors of skin cancers that were not documented in the database, nor could we recognize patients’ compliance with immunosuppressants.

Conclusion

Organ recipients have a greater risk of skin cancer. Clinicians should inform recipients of the importance of photoprotection and regular dermatologic follow-up.

Topical treatment of actinic keratoses in organ transplant recipients: a feasibility study for SPOT (Squamous cell carcinoma Prevention in Organ transplant recipients using Topical treatments)

BACKGROUND

The risk of cutaneous squamous cell carcinoma (cSCC) is significantly increased in organ transplant recipients (OTRs). Clearance of actinic keratoses (AKs) is generally regarded as a surrogate biomarker for cSCC prevention. OTR-cSCC chemoprevention with topical AK treatments has not been investigated in randomized controlled trials (RCTs), although there is evidence that 5% 5-fluorouracil (5-FU) may be chemoprotective in immunocompetent patients.

OBJECTIVES

To assess the feasibility, activity and evaluation outcomes relevant to the design of a future phase III RCT of topical cSCC chemoprevention in OTRs.

METHODS

OTRs with 10 or more AKs in predefined areas were randomized 1 : 1 : 1 to topical 5-FU, 5% imiquimod (IMIQ) or sunscreen (sun-protective factor 30+) in a phase II, open-label RCT over 15 months. Feasibility outcomes included proportions of eligible OTRs randomized, completing treatment and willing to be re-treated. AK activity [AK clearance, new AK development, patient-centred outcomes (toxicity, health-related quality of life, HRQoL)] and evaluation methodology (clinical vs. photographic) were assessed.

RESULTS

Forty OTRs with 903 AKs were randomized. All feasibility outcomes were met (56% of eligible OTRs were randomized; 89% completed treatment; 81% were willing to be re-treated). AK activity analyses found 5-FU and IMIQ were superior to sunscreen for AK clearance and prevention of new AKs. 5-FU was more effective than IMIQ in AK clearance and prevention in exploratory analyses. Although toxicity was greater with 5-FU, HRQoL outcomes were similar.

CONCLUSIONS

Trials of topical AK treatments in OTRs for cSCC chemoprevention are feasible and AK activity results support further investigation of 5-FU-based treatments in future phase III trials. What is already known about this topic? Cutaneous squamous cell carcinoma (cSCC) is significantly more common in immunocompromised individuals including organ transplant recipients (OTRs) compared with immunocompetent populations. cSCC chemoprevention activity of sunscreen and 5-fluorouracil-based (5-FU) actinic keratosis (AK) treatments has been demonstrated in randomized controlled trials (RCTs) in immunocompetent populations but not in OTRs. AKs are cSCC precursors and their clearance and prevention are generally regarded as surrogate endpoint biomarkers for potential cSCC chemoprevention activity. What does this study add? SPOT (SCC Prevention in OTRs using Topical treatments) has confirmed that RCTs of OTR-cSCC chemoprevention with topical AK treatments are feasible. It also suggests that topical 5-FU may be superior to 5% imiquimod and sunscreen in AK clearance and prevention. Together with recent evidence from several RCTs in the general population, these data provide a compelling rationale for further studies of intervention with 5-FU-based topical chemoprevention approaches in OTR-cSCC prevention.

Lymphocyte subsets and Langerhans cells in the skin of kidney transplant recipients under three different immunosuppressive regimens

BACKGROUND

Renal transplant recipients (RTRs) are at increased risk of developing skin cancer; however, the role of immunosuppression is not yet fully understood. In this study, we evaluated the immunohistochemical changes in the skin of RTRs under three different immunosuppression regimens: mTOR inhibitors (mTORi), sirolimus or everolimus, mycophenolic acid (MPA) precursors such as mycophenolate sodium or mofetil, or azathioprine (AZA).

METHODS

We evaluated biopsies of sun-exposed and sun-protected skin for immunohistochemical quantification of B lymphocytes (CD20+), T lymphocytes (CD3+, CD4+, and CD8+), and Langerhans cells (LCs) (CD1a+) in 30 RTRs and 10 healthy controls. The RTRs were divided into three groups: mTORi (n = 10), MPA (n = 10), and AZA (n = 10).

RESULTS

No differences were observed in the number of B lymphocytes. However, a significant decrease in the number of T lymphocytes and LCs was observed in both sun-protected and sun-exposed skin in the AZA and MPA groups, although to a lesser degree in the latter group. The skin of the mTORi group did not differ from that of the control group in terms of the number of B and T lymphocytes and LCs.

CONCLUSIONS

Patients treated with mTORi exhibit preserved cellular elements related to cutaneous immune surveillance. The use of AZA induced a greater degree of skin immunosuppression than in the control group, as demonstrated by the decrease in T lymphocytes and LCs.

Aggressive Cutaneous Squamous Cell Carcinomas Following Treatment for Graft-versus-Host Disease: A Case Report and Review of Risk Factors

A 19-year-old female with a history of pre-B cell acute lymphocytic leukemia (ALL) presented with two aggressive cutaneous squamous cell carcinomas (C-SCC) in the right hand. The patient was diagnosed with pre-B cell ALL at four years of age. She underwent chemotherapy with initial remission. However, recurrence of the pre-B cell ALL required an unrelated allogeneic cord hematopoietic stem cell transplant (alloHSCT). Post-transplant, the patient developed Graft-Versus-Host Disease (GVHD), which was treated with immunosuppressant therapy for six years until resolution. Fourteen years following the transplant, the patient developed a morbilliform drug eruption secondary to clindamycin. She consequently received prednisone treatment. During the treatment period, the patient developed a new ulcerated and tender nodule on the dorsal aspect of her right hand. Further histopathological biopsy confirmed the diagnosis of C-SCC, which required excision. Ten months following the excision, the patient developed an additional C-SCC nodule on the same right hand, separated by 2.6 cm from the prior C-SCC. She was referred for a ray resection procedure. This case illustrates a patient with multiple risk factors that may have contributed to the continued development of C-SCC. Such risk factors include: a prolonged course of immunosuppressant medications and voriconazole treatment. Additional research is needed to investigate the etiologies and risks of C-SCC development in patients who require a transplant and long-duration immunosuppressive therapy.

Update of advanced cutaneous squamous cell carcinoma

The incidence of cutaneous squamous cell carcinoma (cSCC) is rapidly increasing. A growing part of this patient group is formed by immunocompromised patients, for example organ-transplant recipients (OTR). Although over 90% of the cSCC show a relatively harmless clinical behaviour, there is also a chance of developing advanced cSCC and metastases. Locally advanced cSCC are defined as cSCC that have locally advanced progression and are no longer amenable to surgery or radiation therapy. Better understanding of the clinical behaviour of cSCC is essential to discriminate between low- and high-risk cSCC. Staging systems are important and have recently been improved. Genetic characterisation of SCC will likely become an important tool to help distinguish low and high-risk cSCC with an increased potential to metastasise in the near future. Available treatments for high-risk and advanced cSCC include surgery, radiotherapy, chemotherapy and targeted therapy with epidermal growth factor receptors inhibitors. Anti-PD-1 antibodies show promising results with response rates of up to 50% in both locally advanced and metastatic cSCC but, in its present form, is not suitable for OTR.

Non-Melanoma Skin Cancer in People Living With HIV: From Epidemiology to Clinical Management

Skin cancers represent the most common human tumors with a worldwide increasing incidence. They can be divided into melanoma and non-melanoma skin cancers (NMSCs). NMSCs include mainly squamous cell (SCC) and basal cell carcinoma (BCC) with the latest representing the 80% of the diagnosed NMSCs. The pathogenesis of NMSCs is clearly multifactorial. A growing body of literature underlies a crucial correlation between skin cancer, chronic inflammation and immunodeficiency. Intensity and duration of immunodeficiency plays an important role. In immunocompromised patients the incidence of more malignant forms or the development of multiple tumors seems to be higher than among immunocompetent patients. With regards to people living with HIV (PLWH), since the advent of combined antiretroviral therapy (cART), the incidence of non-AIDS-defining cancers (NADCs), such as NMSCs, have been increasing and now these neoplasms represent a leading cause of illness in this particular population. PLWH with NMSCs tend to be younger, to have a higher risk of local recurrence and to have an overall poorer outcome. NMSCs show an indolent clinical course if diagnosed and treated in an early stage. BCC rarely metastasizes, while SCC presents a 4% annual incidence of metastasis. Nevertheless, metastatic forms lead to poor patient outcome. NMSCs are often treated with full thickness treatments (surgical excision, Mohs micro-graphic surgery and radiotherapy) or superficial ablative techniques (such as cryotherapy, electrodesiccation and curettage). Advances in genetic landscape understanding of NMSCs have favored the establishment of novel therapeutic strategies. Concerning the therapeutic evaluation of PLWH, it’s mandatory to evaluate the risk of interactions between cART and other treatments, particularly antiblastic chemotherapy, targeted therapy and immunotherapy. Development of further treatment options for NMSCs in PLWH seems needed. We reviewed the literature after searching for clinical trials, case series, clinical cases and available databases in Embase and Pubmed. We review the incidence of NMSCs among PLWH, focusing our attention on any differences in clinicopathological features of BCC and SCC between PLWH and HIV negative persons, as well as on any differences in efficacy and safety of treatments and response to immunomodulators and finally on any differences in rates of metastatic disease and outcomes.

Skin conditions in liver transplant recipients in a Singapore academic medical center: A retrospective cohort study

Background

Liver transplant recipients are at lifelong risk of immunosuppression-related cutaneous complications, such as malignancy and infection.

Objective

Our study aims to assess the epidemiology of dermatologic conditions among liver transplant recipients in an academic medical center in Singapore.

Methods

Medical records of liver transplant recipients on follow-up with gastroenterology and dermatology departments at the Singapore General Hospital between 2006 and 2021 were retrospectively reviewed. A literature review was subsequently performed on the keywords “liver transplant” and “dermatology.”

Results

A total of 99 liver transplant recipients were identified in this study. Sixty-nine patients (70%) had at least 1 dermatologic condition. Inflammatory skin conditions were the most common (53%), followed by cutaneous infection (36%) and benign cutaneous tumors (30%). Malignant and premalignant lesions were the least common skin conditions reported (10%). Our study results concurred with many other studies reported worldwide, demonstrating a low cutaneous malignancy burden after liver transplantation.

Limitations

The study included a small population size in a single center and did not have a pre-existing protocol for pretransplant dermatologic surveillance.

Conclusion

Although the incidence of skin cancer after liver transplant in Singapore is low, the patients will benefit from long-term dermatology surveillance, given the long-term risks of infection and malignant skin conditions.

Reducing non-melanoma skin cancer risk in renal transplant recipients

With an increasing number of renal transplant recipients (RTRs) and improving patient survival, a higher incidence of non-melanoma skin cancer (NMSC) has been observed. NMSC in RTRs are often more numerous and biologically more aggressive than the general population, thus contributing towards an increase in morbidity and to a lesser degree, mortality. The resultant cumulative health and financial burden is a recognized concern. Proposed strategies in mitigating risks of developing NMSC and early therapeutic options thereof include tailored modification of immunosuppressants in conjunction with sun protection in all transplant patients. This review highlights the clinical and financial burden of transplant-associated skin cancers, carcinogenic mechanisms in association with immunosuppression, importance of skin cancer awareness campaign and integrated transplant skin clinic, and the potential role of chemoprotective agents. A scheme is proposed for primary and secondary prevention of NMSC based on the available evidence.

Involvement of transcribed lncRNA uc.291 and SWI/SNF complex in cutaneous squamous cell carcinoma

While non-melanoma skin cancers (NMSCs) are the most common tumours in humans, only the sub-type cutaneous squamous cell carcinoma (cSCC), might become metastatic with high lethality. We have recently identified a regulatory pathway involving the lncRNA transcript uc.291 in controlling the expression of epidermal differentiation complex genes via the interaction with ACTL6A, a component of the chromatin remodelling complex SWI/SNF. Since transcribed ultra-conserved regions (T-UCRs) are expressed in normal tissues and are deregulated in tumorigenesis, here we hypothesize a potential role for dysregulation of this axis in cSCC, accounting for the de-differentiation process observed in aggressive poorly differentiated cutaneous carcinomas. We therefore analysed their expression patterns in human tumour biopsies at mRNA and protein levels. The results suggest that by altering chromatin accessibility of the epidermal differentiation complex genes, down-regulation of uc.291 and BRG1 expression contribute to the de-differentiation process seen in keratinocyte malignancy. This provides future direction for the identification of clinical biomarkers in cutaneous SCC. Analysis of publicly available data sets indicates that the above may also be a general feature for SCCs of different origins.

The burden of cutaneous disease in solid organ transplant recipients of color

Organ transplant recipients (OTRs) are at increased risk of cutaneous malignancy. Skin disorders in OTRs of color (OTRoC) have rarely been systematically assessed. We aimed to ascertain the burden of skin disease encountered in OTRoC by prospectively collecting data from OTRs attending 2 posttransplant skin surveillance clinics: 1 in London, UK and 1 in Philadelphia, USA. Retrospective review of all dermatological diagnoses was performed. Data from 1766 OTRs were analyzed: 1024 (58%) white, 376 (21%) black, 261 (15%) Asian, 57 (3%) Middle Eastern/Mediterranean (ME/M), and 48 (2.7%) Hispanic; and 1128 (64%) male. Viral infections affected 45.1% of OTRs, and were more common in white and ME/M patients (P < .001). Fungal infections affected 28.1% and were more common in ME/M patients (P < .001). Inflammatory skin disease affected 24.5%, and was most common in black patients (P < .001). In addition, 26.4% of patients developed skin cancer. There was an increased risk of skin cancer in white vs nonwhite OTRs (HR 4.4, 95% CI 3.5-5.7, P < .001): keratinocyte cancers were more common in white OTRs (P < .001) and Kaposi sarcoma was more common in black OTRs (P < .001). These data support the need for programs that promote targeted dermatology surveillance for all OTRs, regardless of race/ethnicity or country of origin.

Post-transplant malignancies in pediatric organ transplant recipients

The majority of cancer diagnoses in pediatric solid organ transplant recipients (SOTRs) are post-transplantation lymphoproliferative disorders (PTLD) or skin cancers. However, pediatric SOTRs are also at significantly elevated risk for multiple other solid and hematological cancers. The risks of specific cancers vary by transplanted organ, underlying disease, and immunosuppression factors. More than one-quarter of pediatric SOTRs develop cancer within 30 years of transplantation and their risk of solid cancer is 14 times greater than the general population. Pediatric SOTRs are at significantly higher risk of cancer-associated death. Improving patient survival among pediatric SOTRs puts them at risk of adult epithelial cancers associated with environmental carcinogenic exposures. Vaccination against oncogenic viruses and avoidance of excessive immunosuppression may reduce the risk of solid cancers following transplantation. Patient and family education regarding photoprotection is an essential component of skin cancer prevention. There is significant variability in cancer screening recommendations for SOTRs and general population approaches are typically not validated for transplant populations. An individualized approach to cancer screening should be developed based on estimated cancer risk, patient life expectancy, and screening test performance.

Immune Checkpoint Blockade in Advanced Cutaneous Squamous Cell Carcinoma: What Do We Currently Know in 2020?

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer that predominantly arises in chronically sun-damaged skin. Immunosuppression, genetic disorders such as xeroderma pigmentosum (XP), exposure to certain drugs and environmental noxae have been identified as major risk factors. Surgical removal of cSCC is the therapy of choice and mostly curative in early stages. However, a minority of patients develop locally advanced tumors or distant metastases that are still challenging to treat. Immune checkpoint blockade (ICB) targeting CTLA-4, PD-L1 and PD-1 has tremendously changed the field of oncological therapy and especially the treatment of skin cancers as tumors with a high mutational burden. In this review, we focus on the differences between cSCC and cutaneous melanoma (CM) and their implications on therapy, summarize the current evidence on ICB for the treatment of advanced cSCC and discuss the chances and pitfalls of this therapy option for this cancer entity. Furthermore, we focus on special subgroups of interest such as organ transplant recipients, patients with hematologic malignancies, XP and field cancerization.

Rate differences between first and second primary cancers may outline immune dysfunction as a key risk factor

Background

Many cancers are increased in immunosuppressed patients and evidence is accumulating that immune dysfunction may be a contributing risk factor for second primary cancers (SPCs). The aim of this study was to explore the potential influence of immune mechanisms in SPC.

Methods

We used the Swedish Cancer Registry (1990‐2015) to select 13 male and 14 female first primary cancers (FPCs) that are known to be related to immune suppression. We assessed relative risks (RRs) for any of these as concordant (same first and second cancer) and discordant FPC‐SPC pairs. Hierarchical clustering of significant RRs was performed for cancers as FPC and SPC.

Results

Concordant risks for SPCs were excessive in men and women for nasal (RRs 59.3 for men and 150.6 for women), tongue/mouth (51.7 and 100.8), and lip (32.4 and 61.2) cancers. Heatmaps showed that some cancers, such as skin cancer, tongue/mouth cancers, and non‐Hodgkin lymphoma had multiple bidirectional associations as FPC and SPC. Nasal cancer and chronic lymphocytic leukemia had associations mainly as FPC while liver and kidney cancers showed most associations as SPC.

Conclusions

Immune dysfunction may be a plausible contributing factor for most of the associations, which calls for experimental verification.

5'-Cap‒Dependent Translation as a Potent Therapeutic Target for Lethal Human Squamous Cell Carcinoma

Skin squamous cell carcinomas (SCCs) are a major cause of death in patients who have undergone or will undergo organ transplantation. Moreover, these neoplasms cause significant disease and economic burden and diminish patients' life quality. However, no effective treatment or intervention strategies are available. In this study, we investigated the pathologic role of 5'-cap translation, which is regulated by the formation of a ternary initiation factor complex involving eIF4E, eIF4G, and eIF4A1. We detected increased expression of phosphorylated eIF4E, eIF4G, and eIF4A1 in human and murine skin SCCs. The increase in these ternary initiation factor complex proteins was associated with enhanced eIF4E translation targets cyclin D1 and c-Myc. Conversely, small interfering RNA-mediated depletion of eIF4E in human SCC cells (A431 and SCC-13) reduced eIF4G and proteins that regulate the cell cycle and proliferation. Notably, inhibition of Raf/MAPK/extracellular signal-regulated kinase signaling decreased eIF4E and phosphorylated eIF4E accumulation and significantly diminished cell-cycle gene expression and tumor volume of A431-derived xenograft tumors. Furthermore, disrupting the eIF4E with an allosteric inhibitor of eIF4E and eIF4G binding, 4EGI-1, decreased the eIF4E/eIF4G expression and reduced the proliferation. Finally, combined inhibition of the Raf/MAPK/extracellular signal-regulated kinase axis and eIF4E impaired 5'-cap‒dependent translation and abrogated tumor cell proliferation. These data demonstrate that 5'-cap‒dependent translation is a potential therapeutic target for abrogating lethal skin SCCs in patients who have undergone or will undergo organ transplantation.

Incidence Differences Between First Primary Cancers and Second Primary Cancers Following Skin Squamous Cell Carcinoma as Etiological Clues

Background

Most literature on second primary cancers (SPCs) focuses on possible factors, which may increase the risk of these cancers, and little attention has been paid for the overall incidence differences between first primary cancers (FPCs) and same SPCs. We wanted to compare the incidence rates for all common cancers when these were diagnosed as FPCs and SPCs after invasive and in situ squamous cell carcinoma (SCC) of the skin, which are usually treated by surgery only.

Methods

Cancers were identified from the Swedish Cancer Registry from the years 1990 through to 2015, and they included, in addition to skin cancers, 20 male cancers totaling 484,850 patients and 22 female cancers totaling 452,909 patients. Standardized incidence rates and relative risks (RRs) were calculated for sex-specific common cancers as FPC and as SPC after skin SCC. Spearman rank correlations were used in the analysis of incidence ranking of FPC and SPC.

Results

Of total, 29,061 men and 23,533 women developed invasive SCC and 27,842 men and 36,383 women in situ SCC. The total number of 20 other male cancers was 484,850 and of 22 female cancers it was 452,909. Rank correlations ranged from 0.90 to 0.96 (P~5×10^-6), indicating that overall skin SCC did not interfere with SPC formation. The exceptions were increased SPC risks for melanoma, sharing risk factors with skin SCC, and non-Hodgkin and Hodgkin lymphoma, and cancers of the upper aerodigestive tract, connective tissue, and male and female genitals suggesting contribution by skin cancer initiated immune dysfunction.

Conclusion

The incidence ranking of SPCs after skin cancers largely follows the incidence ranking of FPCs indicating that overall skin SCC does not greatly interfere with the intrinsic carcinogenic process. The main deviations in incidence between FPC and SPC appeared to be due to shared risk factors or immunological processes promoting immune responsive cancer types.

Human papillomavirus type 38 alters wild-type p53 activity to promote cell proliferation via the downregulation of integrin alpha 1 expression

Tumor suppressors can exert pro-proliferation functions in specific contexts. In the beta human papillomavirus type 38 (HPV38) experimental model, the viral proteins E6 and E7 promote accumulation of a wild-type (WT) p53 form in human keratinocytes (HKs), promoting cellular proliferation. Inactivation of p53 by different means strongly decreases the proliferation of HPV38 E6/E7 HKs. This p53 form is phosphorylated at S392 by the double-stranded RNA-dependent protein kinase PKR, which is highly activated by HPV38. PKR-mediated S392 p53 phosphorylation promotes the formation of a p53/DNMT1 complex, which inhibits expression of integrin alpha 1 (ITGA1), a repressor of epidermal growth factor receptor (EGFR) signaling. Ectopic expression of ITGA1 in HPV38 E6/E7 HKs promotes EGFR degradation, inhibition of cellular proliferation, and cellular death. Itga1 expression was also inhibited in the skin of HPV38 transgenic mice that have an elevated susceptibility to UV-induced skin carcinogenesis. In summary, these findings reveal the existence of a specific WT p53 form that displays pro-proliferation properties.

Beta human papillomaviruses infection and skin carcinogenesis

During the last decade, the worldwide incidence of keratinocyte carcinomas (KC) has increased significantly. They are now the most common malignancy, representing approximately 30% of all cancers. The role of ultraviolet (UV) radiation as a major environmental risk factor for skin cancers is well recognized. The aim of this review is to analyse the current understanding of the nature of beta-human papillomavirus (HPV) and its association with KC and explore the implications for the management and prevention of these cancers. A comprehensive review of the literature on beta-HPV and its association with KC was undertaken, the results reported in the form of a narrative review. A subgroup of HPV that infects the mucosal epithelia of the genital tract has been firmly associated with carcinogenesis. In addition, some HPV types with cutaneous tropism have been proposed to cooperate with UV in the development of KC. The first evidence for this association was reported in 1922 in patients with epidermodysplasia verruciformis (EV). Since then, epidemiological studies have highlighted the higher risk of skin cancer in patients with EV and certain cutaneous HPV types, and in vitro studies have elucidated molecular mechanisms and transforming properties of beta-HPV. Furthermore, in vivo research conducted on transgenic mice models has shown the possible role of beta-HPV in cutaneous carcinogenesis as a co-factor with UV radiation and immunosuppression. There is good evidence supporting the role of beta-HPV in the oncogenesis of KC. The high prevalence of beta-HPV in human skin and the worldwide burden of KC makes the search for an effective vaccine relevant and worthwhile.

Genetic and environmental factors underlying keratinocyte carcinoma risk

Recent large-scale GWAS and large epidemiologic studies have accelerated the discovery of genes and environmental factors that contribute to the risk of keratinocyte carcinoma (KC), which includes basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). This Review summarizes the genomic regions associated with SCC and BCC risk, examines the genetic overlap between SCC and BCC, and discusses biological pathways involved in SCC and BCC development. Next, we review environmental factors that are associated with KC risk, including those that are shared between SCC and BCC as well as others that associated with only one type of KC. We conclude with a critical appraisal of current research and potential directions for future research.

The Role of Beta HPV Types and HPV-Associated Inflammatory Processes in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is a common form of skin cancer with a complex but not fully understood pathogenesis. Recent research suggests the role of beta human papillomavirus (HPV) types and HPV-associated inflammatory processes in cSCC development. Beta HPV types are components of the normal flora; however, under the influence of certain cofactors, the virus may trigger a malignant process. Dysregulation of the immune system (chronic inflammation and immunosuppression), environmental factors (ultraviolet radiation), and genetic factors are the most important cofactors involved in beta HPV-related carcinogenesis. In addition, the oncoproteins E6 and E7 of beta HPV types differ biochemically from their counterparts in the structure of alpha HPV types, resulting in different mechanisms of action in carcinogenesis. The aim of our manuscript is to present an updated point of view on the involvement of beta HPV types in cSCC pathogenesis.

The case for BK polyomavirus as a cause of bladder cancer

In 2014, the International Agency for Research on Cancer judged Merkel cell polyomavirus (MCPyV) to be a probable human carcinogen. BK polyomavirus (BKPyV, a distant cousin of MCPyV) was ruled a possible carcinogen. In this review, we argue that it has recently become reasonable to view both of these viruses as known human carcinogens. In particular, several complementary lines of evidence support a causal role for BKPyV in the development of bladder carcinomas affecting organ transplant patients. The expansion of inexpensive deep sequencing has opened new approaches to investigating the important question of whether BKPyV causes urinary tract cancers in the general population.

Association between Human Leukocyte Antigen Type and Keratinocyte Carcinoma Risk in Renal Transplant Recipients

Keratinocyte carcinoma (KC), defined as squamous cell carcinoma and basal cell carcinoma, is the most common malignancy among white, non-Hispanic renal transplant recipients. Although recent genome-wide association studies reported that class II HLA is associated with KC risk, epidemiologic data on HLA type and KC risk in renal transplant recipients is limited. Using an institutional cohort of white, non-Hispanic renal transplant recipients transplanted between 1993 and 2017, we examined the association between pretransplant molecular HLA types and KC risk. Posttransplant KCs were captured using the International Classification of Diseases codes and validated using pathology reports. Cox proportional hazards regression models were used to estimate hazard ratios of incident KC, squamous cell carcinoma, and basal cell carcinoma, adjusting for age, male sex, history of KC, Charlson comorbidity index, HLA mismatch, transplant type, year of transplant, and the type of immunosuppression. Among 617 subjects (mean age 53 years, 67% male), 10% developed posttransplant KC. Multivariable Cox regression analyses showed HLA-DRB1∗13 was associated with KC risk (hazard ratio, 1.84; 95% confidence interval, 1.00-3.38) and squamous cell carcinoma risk (hazard ratio, 2.24; 95% confidence interval, 1.12-4.49), whereas HLA-DRB1∗14 (hazard ratio, 2.81; 95% confidence interval, 1.14-6.91) was associated with basal cell carcinoma risk. Our findings suggest that a subset of renal transplant recipients with specific HLA polymorphisms may be at increased KC risk.

Aggressive Squamous Cell Carcinoma in Organ Transplant Recipients

Importance

Squamous cell carcinoma (SCC) is the most frequent malignant neoplasm found in solid organ transplant recipients and is associated with a more aggressive disease course and higher risk of metastasis and death than in the general population.

Objectives

To report the clinicopathologic features of and identify factors associated with aggressive SCC in solid organ transplant recipients.

Methods

This retrospective multicentric case series included 51 patients who underwent solid organ transplantation and were found to have aggressive SCC, defined by nodal or distant metastasis or death by local progression of primary SCC. Standard questionnaires were completed by the researchers between July 18, 2005, and January 1, 2015. Data were analyzed between February 22, 2016, and July 12, 2016.

Results

Of the 51 participants, 43 were men and 8 were women, with a median age of 51 years (range, 19-71 years) at time of transplantation and 62 years (range, 36-77 years) at time of diagnosis of aggressive SCC. The distribution of aggressive SCC was preferentially on the face (34 [67%]) and scalp (6 [12%]), followed by the upper extremities (6 [12%]). A total of 21 tumors (41%) were poorly differentiated, with a median tumor diameter of 18.0 mm (range, 4.0-64.0 mm) and median tumor depth of 6.2 mm (range, 1.0-20.0 mm). Perineural invasion was present in 20 patients (39%), while 23 (45%) showed a local recurrence. The 5-year overall survival rate was 23%, while 5-year disease-specific survival was 30.5%.

Conclusions and Relevance

Results of this case series suggest that anatomical site, differentiation, tumor diameter, tumor depth, and perineural invasion are important risk factors in aggressive SCC in solid organ transplant recipients.

The Role of the Immune System in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer. In immunosuppressed populations it is a source of considerable morbidity and mortality due to its enhanced recurrence and metastatic potential. In common with many malignancies, leucocyte populations are both protective against cancer development and also play a role in 'sculpting' the nascent tumor, leading to loss of immunogenicity and tumor progression. UV radiation and chronic viral carriage may represent unique risk factors for cSCC development, and the immune system plays a key role in modulating the response to both. In this review, we discuss the lessons learned from animal and ex vivo human studies of the role of individual leucocyte subpopulations in the development of cutaneous SCC. We then discuss the insights into cSCC immunity gleaned from studies in humans, particularly in populations receiving pharmacological immunosuppression such as transplant recipients. Similar insights in other malignancies have led to exciting and novel immune therapies, which are beginning to emerge into the cSCC clinical arena.

Rapidly Growing and Aggressive Cutaneous Squamous Cell Carcinomas in a Patient Treated with Ruxolitinib

Ruxolitinib is a Janus kinase (JAK)1 and JAK2 inhibitor approved for the treatment of myelofibrosis and for polycythemia patients who are resistant or intolerant to hydroxyurea. We report a 72 year-old man patient with polycythemia vera who developed multiple cutaneous squamous cell carcinomas (cSCCs) with keratoacanthoma-like histological features while on treatment with ruxolitinib. Similar lesions have been reported in an isolated patient who also received ruxolitinib. Our case confirms that ruxolitinib may induce eruptive cSCCs with characteristic clinical and histological features that differentiate them from conventional non-drug induced lesions. Moreover, we performed a mutational panel analysis of the tumors. The lack of specific mutations in these tumors suggests an impairment of immunosurveillance in the origin of the cutaneous lesions. Frequent and thorough dermatological examinations in patients receiving ruxolitinib with a history of photodamage, skin cancer and/or previous hydroxyurea intake is thus recommended.

Occurrence of newly discovered human polyomaviruses in skin of liver transplant recipients and their relation with squamous cell carcinoma in situ and actinic keratosis - a single-center cohort study

To date 14 human polyomaviruses (HPyVs) have been identified. The newly found HPyVs have not been examined with regard to post-transplant skin carcinogenesis. To determine the occurrences in skin and possible pathological associations of the HPyVs, we studied their genoprevalences in squamous cell carcinoma (SCC) in situ or actinic keratosis and benign skin in liver transplant recipients (LiTRs); and of healthy skin in immunocompetent adults. We used highly sensitive and specific HPyV PCRs of two types. Overall, Merkel cell polyomavirus (MCPyV), human polyomavirus 6 (HPyV6), human polyomavirus 7 (HPyV7), trichodysplasia spinulosa polyomavirus (TSPyV), and Lyon IARC polyomavirus (LIPyV) were found in 58/221 (26.2%) skin biopsies. MCPyV DNA was detected in 5/14 (35.7%) premalignant vs. 32/127 (25.2%) benign skin of LiTRs, and in 12/80 (15%) healthy skin of immunocompetent adults, with no statistically significant difference in viral DNA prevalence or load. TSPyV DNA was found in a single skin lesion. LIPyV, HPyV6 and HPyV7 DNAs occurred exclusively in benign skin. Overall, the viral findings in premalignant versus benign skin were alike. The occurrences of HPyVs in skin of LiTRs and immunocompetent individuals speak against a role for any of the 14 HPyVs in SCC development.

The Role of Human Papillomaviruses and Polyomaviruses in BRAF-Inhibitor Induced Cutaneous Squamous Cell Carcinoma and Benign Squamoproliferative Lesions

Background: Human papillomavirus (HPV) has long been proposed as a cofactor in the pathogenesis of cutaneous squamous cell carcinoma (cSCC). More recently, the striking clinico-pathological features of cSCCs that complicate treatment of metastatic melanoma with inhibitors targeting BRAF mutations (BRAFi) has prompted speculation concerning a pathogenic role for oncogenic viruses. Here, we investigate HPV and human polyomaviruses (HPyV) and correlate with clinical, histologic, and genetic features in BRAFi-associated cSCC.

Materials and Methods: Patients receiving BRAFi treatment were recruited at Barts Health NHS Trust. HPV DNA was detected in microdissected frozen samples using reverse line probe technology and degenerate and nested PCR. HPV immunohistochemistry was performed in a subset of samples. Quantitative PCR was performed to determine the presence and viral load of HPyVs with affinity for the skin (HPyV6, HPyV7, HPyV9, MCPyV, and TSPyV). These data were correlated with previous genetic mutational analysis of H, K and NRAS, NOTCH1/2, TP53, CDKN2A, CARD11, CREBBP, TGFBR1/2. Chromosomal aberrations were profiled using single nucleotide polymorphism (SNP) arrays.

Results: Forty-five skin lesions from seven patients treated with single agent vemurafenib in 2012–2013 were analyzed: 12 cSCC, 19 viral warts (VW), 2 actinic keratosis (AK), 5 verrucous keratosis/other squamoproliferative (VK/SP) lesions, one melanocytic lesion and 6 normal skin samples. Significant histologic features of viral infection were seen in 10/12 (83%) cSCC. HPV DNA was detected in 18/19 (95%) VW/SP, 9/12 (75%) cSCC, 4/5 (80%) SP, and 3/6 (50%) normal skin samples and in 1/12 cases assessed by immunohistochemistry. HPyV was co-detected in 22/30 (73%) of samples, usually at low viral load, with MCPyV and HPyV7 the most common. SNP arrays confirmed low levels of chromosomal abnormality and there was no significant correlation between HPV or HPyV detection and individual gene mutations or overall mutational burden.

Conclusion: Despite supportive clinicopathologic evidence, the role for HPV and HPyV infection in the pathogenesis of BRAFi-induced squamoproliferative lesions remains uncertain. Synergistic oncogenic mechanisms are plausible although speculative. Nonetheless, with the prospect of a significant increase in the adjuvant use of these drugs, further research is justified and may provide insight into the pathogenesis of other BRAFi-associated malignancies.

Skin Cancer Following Solid Organ Transplantation: A Review of Risk Factors and Models of Care

The number of solid organ transplants has been increasing annually worldwide. Advances in transplantation surgery and community awareness of organ donation have been key contributors. Combined with increased understanding of immunosuppression, there are a growing number of solid organ transplant recipients in the community as a result of improved long-term outcomes. There remains a high incidence of deaths worldwide post-transplant due to non-melanoma skin cancer (NMSC), which has greater morbidity and mortality in this population than in the general community. Many transplant candidates are not screened prior to organ transplantation and not followed up dermatologically after transplant. After a comprehensive review of the MEDLINE database, we present an update of literature on risk factors for melanoma and non-melanoma skin cancer development in transplant recipients. Medications used by transplant recipients, including immunosuppressants and antibiotics, are discussed along with their respective risks of skin cancer development. We conclude with evidence-based recommendations for models of care, including patient education and dermatological review of transplant recipients.