Cutaneous Squamous Cell Carcinomas in Organ Transplant Recipients

Mining metagenomes and metatranscriptomes unveils viruses associated with cutaneous squamous cell carcinoma in hematopoietic stem cell transplant recipients

We investigated the presence of viral DNA and RNA in cutaneous squamous cell carcinoma (cSCC) tumor and normal tissues from nine individuals with a history of hematopoietic stem cell transplantation (HCT). Microbiome quantification through DNA and RNA sequencing (RNA-seq) revealed the presence of 18 viruses in both tumor and normal tissues. DNA sequencing (DNA-seq) identified Torque teno virus, Saimiriine herpesvirus 1, Merkel cell polyomavirus, Human parvovirus B19, Human gammaherpesvirus-4, Human herpesvirus-6, and others. RNA-seq revealed additional viruses such as Tobamovirus, Pinus nigra virus, Orthohepadnavirus, Human papillomavirus-5, Human herpesvirus-7, Human gammaherpesvirus-4, Gammaretrovirus, and others. Notably, DNA-seq indicated that tumor samples exhibited low levels of Escherichia virus in three out of nine subjects and elevated levels of Human gammaherpesvirus-4 in one subject, while normal samples frequently contained Gammaretrovirus and occasionally Escherichia virus. A comparative analysis using both DNA- and RNA-seq captured three common viruses: Abelson murine leukemia virus, Murine type C retrovirus, and Human gammaherpesvirus-4. These findings were corroborated by an independent data set, supporting the reliability of the viral detection methods utilized. The study provides insights into the viral landscape in post-HCT patients, emphasizing the need for comprehensive viral monitoring in this vulnerable population.

IMPORTANCE

This study is important because it explores the potential role of viruses in the development of cSCC in individuals who have undergone allogeneic HCT. cSCC is common in this population, particularly in those with chronic graft-versus-host disease on long-term immunosuppression. By using advanced metagenomic and metatranscriptomic next-generation sequencing, we aimed to identify viral pathogens present in tumor and adjacent normal tissue. The results could lead to targeted preventive or therapeutic interventions for these high-risk people, potentially improving their outcomes and management of cSCC.

Treatment and Prevention of HPV-Associated Skin Tumors by HPV Vaccination

HPV-associated dermatological diseases include benign lesions like cutaneous warts and external genital warts. In addition, HPV infection is associated with the development of epithelial skin cancers, in particular cutaneous squamous cell carcinoma (cSCC). In contrast to anogenital and oropharyngeal cancers caused by mucosal HPV types of genus alpha papillomavirus, cSCC-associated HPV types belong to the genus beta papillomavirus. Currently available HPV vaccines that target mucosal HPV types associated with anogenital cancer and genital warts are type-specific and provide no cross-protection against beta HPV. When implementing vaccination to beta HPV to prevent skin tumors, it must be considered that acquisition of these HPV types occurs early in childhood and that the risk for cSCC increases with growing age and decreasing immune surveillance. Thus, individuals considered for beta HPV vaccination usually have pre-existing infection and are largely immunocompromised. On the other hand, worldwide increasing incidence rates of epithelial skin cancer reflect an urgent need for skin cancer prevention measures. Based on the pathogenic involvement of beta HPV, vaccination may represent a promising prevention strategy. Indeed, various procedures of prophylactic and therapeutic vaccination have been developed, and some of them have shown efficiency in animal models. Thus far, however, none of these vaccine candidates has been approved for application in humans.

Immune Checkpoints and Cellular Landscape of the Tumor Microenvironment in Non-Melanoma Skin Cancer (NMSC)

Non-melanoma skin cancer (NMSC) is primarily categorized into basal cell carcinoma (BCC), the most prevalent form of skin cancer, and cutaneous squamous cell carcinoma (cSCC), the second most common type. Both BCC and cSCC represent a significant health burden, particularly in immunocompromised individuals and the elderly. The immune system plays a pivotal role in the development and progression of NMSC, making it a critical focus for therapeutic interventions. This review highlights key immunological targets in BCC and cSCC, with a focus on immune checkpoint molecules such as PD-1/PD-L1 and CTLA-4, which regulate T cell activity and contribute to immune evasion. This review also highlights anti-tumor immune cell subsets within the tumor microenvironment (TME), such as tumor-infiltrating lymphocytes (TILs) and dendritic cells. Additionally, it examines the immunosuppressive elements of the TME, including regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and cancer-associated fibroblasts (CAFs), as well as their roles in NMSC progression and resistance to therapy. Emerging strategies targeting these immune elements, such as monoclonal antibodies, are also discussed for their potential to enhance anti-tumor immune responses and improve clinical outcomes. By elucidating the immunological landscape of BCC and cSCC and drawing comparisons to melanoma, this review highlights the transformative potential of immunotherapy in treating these malignancies.

Mohs Micrographic Surgery for Cutaneous Squamous Cell Carcinoma

BACKGROUND

The first-line treatment of the localized form of cutaneous squamous cell carcinoma (cSCC) remains surgical excision. Either conventional excision (CE) with margins or Mohs micrographic surgery (MMS) may be preferred, depending on the risk factors of cSCC, the characteristics of the tumor, and the available technical facilities.

METHODS

This article presents a systematic review of the current literature spanning from 1974 to 2023, comparing outcomes of cSCC treated with MMS versus cSCC treated with conventional excision.

RESULTS

Out of the 6821 records identified through the database search, a total of 156 studies were screened, of which 10 were included in the review. The majority of the included studies showed that treatment of cSCC with MMS consistently exhibits a significantly lower risk of recurrence compared to treatment with CE. In addition, MMS is emerging as the preferred technique for the resection of cSCC located in aesthetically or functionally challenging anatomical areas.

CONCLUSION

The studies generally demonstrate that MMS is a safer and more effective treatment of cSCC than CE. Nevertheless, outcomes such as recurrence rates and cost-effectiveness should be assessed more precisely, in order to allow for a more tailored approach in determining the appropriate indication for the use of MMS.

European consensus-based interdisciplinary guideline for diagnosis, treatment and prevention of actinic keratoses, epithelial UV-induced dysplasia and field cancerization on behalf of European Association of Dermato-Oncology, European Dermatology Forum, European Academy of Dermatology and Venereology and Union of Medical Specialists (Union Européenne des Médecins Spécialistes)

A collaboration of multidisciplinary experts from the European Association of Dermato-Oncology, the European Dermatology Forum, the European Academy of Dermatology and Venereology, and the European Union of Medical Specialists was formed to develop European recommendations on AK diagnosis and treatment, based on current literature and expert consensus. This guideline addresses the epidemiology, diagnostics, risk stratification and treatments in immunocompetent as well as immunosuppressed patients. Actinic keratoses (AK) are potential precursors of cutaneous squamous cell carcinoma (cSCC) and display typical histopathologic and immunohistochemical features of this malignancy in an early stage. They can develop into cSSC in situ and become invasive in a low percentage of cases. AK is the most frequent neoplasia in white populations, frequently occurring within a cancerous field induced by ultraviolet radiation. Since it cannot be predicted, which lesion will progress to cSCC and when treatment is usually recommended. The diagnosis of AK and field cancerization is made by clinical examination. Dermatoscopy, confocal microscopy, optical coherence tomography or line-field confocal-OCT can help in the differential diagnosis of AK and other skin neoplasms. A biopsy is indicated in clinically and/or dermatoscopically suspicious and/or treatment-refractory lesions. The choice of treatment depends on patients' and lesion characteristics. For single non-hyperkeratotic lesions, the treatment can be started upon patient's request with destructive treatments or topical treatments. For multiple lesions, field cancerization treatment is advised with topical treatments and photodynamic therapy. Preventive measures such as sun protection, self-examination and repeated field cancerization treatments of previously affected skin areas in high-risk patients are advised.

Effect of education on sun-safe behaviour in kidney transplant recipients

BACKGROUND

Organ transplant recipients (OTR) are more likely to develop skin cancer than the general population. One of the main components of the exposome that triggers the development of skin tumours is solar ultraviolet (UV) radiation. To reduce the incidence of harmful consequences of sun exposure, sun protection education is needed for patients taking long-term immunosuppressive drugs.

METHODS

In a previous study, we assessed the sun-safe behaviour of 221 OTR using a questionnaire before and after transplantation and personally educated the patients about proper sun protection. After the education, there were no further reminder presentations. Presently, the sun protection and sun seeking habits of the available 176 of these patients were questioned to assess the long-term effect of the previous sun protection education.

RESULTS

Two-four years after the education, more patients wore hats and protected their skin with long-sleeved clothing than before the education. In terms of sun seeking habits, both occupational and recreational sun exposure decreased significantly. Significantly fewer people went on holiday after transplantation, but those who went on holiday spent significantly less time in the sun.

CONCLUSION

The long-term positive effects of education can be seen both in the patients' sun protection and in their sun seeking habits. However, the long-term goal is to maintain these results and thereby reduce the likelihood of skin tumours and consequently the associated tumour death.

Nivolumab + Tacrolimus + Prednisone ± Ipilimumab for Kidney Transplant Recipients With Advanced Cutaneous Cancers

PURPOSE

Cancer-related mortality rates among kidney transplant recipients (KTR) are high, but these patients have largely been excluded from trials of immune checkpoint inhibitors because of immunosuppression and risk of treatment-related allograft loss (TRAL). We conducted a prospective clinical trial testing nivolumab (NIVO) + tacrolimus (TACRO) + prednisone (PRED) ± ipilimumab (IPI) in KTR with advanced cutaneous cancers.

METHODS

Adult KTR with advanced melanoma or basal, cutaneous squamous, or Merkel cell carcinomas were eligible. Immunosuppression was standardized to TACRO (serum trough 2-5 ng/mL) + PRED 5 mg once daily. Patients then received NIVO 480 mg IV once every 4 weeks. The primary composite end point was partial or complete (tumor) response (CR) or stable disease per RECIST v1.1 without allograft loss at 16W. Patients with progressive disease (PD) could receive IPI 1 mg/kg IV + NIVO 3 mg/kg once every 3 weeks × 4 followed by NIVO. Donor-derived cell-free DNA (dd-cfDNA) levels were measured approximately once every 2 weeks as a potential predictor of allograft rejection.

RESULTS

Among eight evaluable patients, none met the trial's primary end point. All eight patients experienced PD on NIVO + TACRO + PRED; TRAL occurred in one patient. Six patients then received IPI + NIVO + TACRO + PRED. Best overall responses: two CR (one with TRAL) and four PD (one with TRAL). In total, 7 of 8 pre-NIVO tumor biopsies contained a paucity of infiltrating immune cells. In total, 2 of 5 on-NIVO biopsies demonstrated moderate immune infiltrates; both patients later experienced a CR to IPI + NIVO. In 2 of 3 patients with TRAL, dd-cfDNA elevations occurred 10 and 15 days before increases in serum creatinine.

CONCLUSION

In most KTR with advanced skin cancer, TACRO + PRED provides insufficient allograft protection and compromises immune-mediated tumor regression after administration of NIVO ± IPI. Elevated dd-cfDNA levels can signal treatment-related allograft rejection earlier than rises in serum creatinine.

Early Results of a Screening Program for Skin Cancer in Liver Transplant Recipients: A Cohort Study

(1) Background: Skin cancer is the most common cancer in transplant recipients. Timely and regular screening may reduce advanced disease. The study aimed to determine referral rates to screening, the incidence, and risk factors of skin cancer in a Danish liver transplant recipient cohort. (2) Methods: All first-time liver transplant recipients, >18 years old, attending outpatient care between January 2018 and December 2021 were included. The referral rates and incidence of skin cancer/preneoplastic lesions were calculated. Risk factors were assessed using Cox regression analyses. (3) Results: Of the 246 included recipients, 219 (89.0%) were referred to screening, and 102 skin cancer/preneoplastic lesions were diagnosed in 32 (15.6%) recipients. The IR of any skin cancer/preneoplastic lesion was 103.2 per 1000 person-years. BCC was the most frequent skin cancer followed by SCC, IR: 51.3 vs. 27.1 per 1000 person-years, respectively. No cases of MM were observed. The IR of actinic keratosis and Bowen's Disease were 48.1 vs. 13.2 per 1000 person-years, respectively. Time since transplantation was independently associated with skin cancer/preneoplastic lesions, HR (95%CI) 2.81 (1.64-4.80). (4) Conclusions: The study determined the incidence and risk factors of skin cancer/preneoplastic lesions in liver transplant recipients enrolled in a screening program, while demonstrating a high screening referral rate.

Cemiplimab for Kidney Transplant Recipients With Advanced Cutaneous Squamous Cell Carcinoma

PURPOSE

Cemiplimab is approved for treating locally advanced or metastatic cutaneous squamous cell carcinoma (CSCC). Solid organ transplant recipients have been excluded from immunotherapy trials, given concern for allograft rejection despite their increased risk of skin cancers. Chronic immunosuppression is necessary to prevent organ rejection but may attenuate antitumor response with PD-1 inhibitors.

METHODS

We report a phase I study of cemiplimab for kidney transplant recipients (KTRs) with advanced CSCC. After cross-taper to a mammalian target of rapamycin (mTOR) inhibitor and pulsed dose corticosteroids (prednisone 40 mg once daily, the day before and on days 1-3 of each cycle, followed by 20 mg once daily on days 4-6, then 10 mg once daily until the day before each subsequent cycle), patients received cemiplimab 350 mg intravenously once every 3 weeks for up to 2 years and were assessed for response every 8 weeks. The primary end point was the rate of kidney rejection, with key secondary end points including rate and duration of response, and survival.

RESULTS

Twelve patients were treated. No kidney rejection or loss was observed. A response to cemiplimab was observed in five of 11 evaluable patients (46%; 90% CI, 22 to 73), including two with durable responses beyond a year. Median follow-up was 6.8 months (range, 0.7-29.8). Treatment-related grade 3 or greater adverse events occurred in five patients (42%), including diarrhea, infection, and metabolic disturbances. One patient died of angioedema and anaphylaxis attributed to mTOR inhibitor cross-taper.

CONCLUSION

mTOR inhibitor and corticosteroids represent a favorable immunosuppressive regimen for KTRs with advanced CSCC receiving immunotherapy. This combination resulted in durable antitumor responses with no kidney rejection events (funded by Regeneron Pharmaceuticals [ClinicalTrials.gov identifier: NCT04339062]).

Efficacy and safety of tirbanibulin 1% ointment in actinic keratoses: Data from two phase-III trials and the real-life clinical practice presented at the European Academy of Dermatology and Venereology Congress 2022

BACKGROUND

The 31st European Academy of Dermatology and Venereology (EADV) Congress took place between 7th and 10th of September 2022 in Milan, Italy.

OBJECTIVES

We report presented clinical data on the efficacy/effectiveness, safety and tolerability of tirbanibulin 1% ointment that has recently been licensed for actinic keratosis (AK) of the face or scalp in adults.

METHODS

Summary of presentations given at the EADV Congress.

RESULTS

Prof. Pellacani presented two post hoc analyses from two phase-III trials with AK patients (NCT03285477 [N = 351] and NCT03285490 [N = 351]): A descriptive analysis of medical history, concomitant medications, and safety results confirming a favourable profile for tirbanibulin showing that number of baseline AK lesions was not correlated to severity of local skin reactions. The latter analysis showed that cases of tirbanibulin application site pain or pruritus were few, and most were found to be mild. Prof. Kunstfeld reported six real-life clinical cases in Austria showing good tirbanibulin effectiveness, safety and tolerability for the treatment of new or recurring AK lesions. Results demonstrated that after 2- to 4-month follow-up, tirbanibulin was well tolerated and effective in AK patients. Presentations by Dr. Patel confirmed good outcomes and tolerability of tirbanibulin in Olsen grade 1-2 AK (N = 12) and porokeratosis patients (N = 4) treated once daily for 5 consecutive days in the United Kingdom. Furthermore, real-world experience in solid organ transplant recipients (N = 2) demonstrated effectiveness of tirbanibulin in skin field cancerization treatment. A symposium sponsored by Almirall was conducted during the congress in which Dr. Hadshiew and Dr. Lear brought together their clinical experience in Germany and the United Kingdom respectively. Interesting clinical cases of 5 consecutive days of tirbanibulin treatment compared to other treatments were discussed with attendees, as well as current treatment needs of AK patients.

CONCLUSIONS

This article provides an overview of presentations and symposium discussions, summarizing key phase-III results and real-life clinical experience with tirbanibulin shared by dermatologists across Europe.

Squamous carcinogenesis: potential truncal mutations

Squamous carcinogenesis is incompletely understood, but more recent genetic studies support that the order of acquired mutations is important. This paper will review more recent genetic studies with an emphasis on the potential truncal mutations, mutations critical to the trunk of the cancer evolutionary tree, in actinic keratosis, squamous cell carcinoma in situ, cutaneous squamous cell carcinoma, keratoacanthoma, and keratoacanthoma-like squamous proliferation.

Immune Checkpoint Inhibitors in Advanced Cutaneous Squamous Cell Carcinoma: Real-World Experience from a Canadian Comprehensive Cancer Centre

Immune checkpoint inhibitors (ICI) cemiplimab and pembrolizumab have revolutionized the treatment of advanced cutaneous squamous cell carcinoma (cSCC). We aimed to evaluate the effectiveness and safety of ICI in a real-world cSCC population, including patients with conditions that would exclude clinical trial participation. In this single-center, retrospective cohort study, we included all non-trial patients with advanced cSCC treated with ICI between 2017 and 2022. We evaluated investigator-assessed best overall response (BOR) and immune-related adverse events (irAEs). We correlated survival outcomes with age, performance status, immune status and irAEs. Of the 36 patients identified, the best overall response (BOR) to ICI was a partial response (PR) in 41.7%, a complete response (CR) in 27.8%, and stable disease in (SD) 13.9%. The progression-free survival (PFS) rate for 1 year was 58.1%; the median PFS was 21.3 months (95% CI 6.4-NE). The 1-year overall survival (OS) was 76.7%, and the median OS was 38.6 months (95% CI 25.4-NE). Immune-compromised patients, ECOG performance 2-3, and age ≥ 75 years were not significantly associated with PFS or OS. IrAE grades 3-4 were seen in 13.9% of patients. In our Canadian experience with real-world patients, ICI was an effective and safe treatment for advanced cSCC patients. Patients achieved great benefits with ICI regardless of age, immune status or ECOG performance status. We acknowledge the small sample size and retrospective methodology as the main limitations of our study.

The Anti-Tumorigenic Role of Cannabinoid Receptor 2 in Non-Melanoma Skin Cancer

Five million non-melanoma skin cancers occur globally each year, and it is one of the most common malignant cancers. The dysregulation of the endocannabinoid system, particularly cannabinoid receptor 2 (CB2), is implicated in skin cancer development, progression, and metastasis. Comparing wildtype (WT) to systemic CB2 knockout (CB2^-/-) mice, we performed a spontaneous cancer study in one-year old mice, and subsequently used the multi-stage chemical carcinogenesis model, wherein cancer is initiated by 7,12-dimethylbenz[a]anthracene (DMBA) and promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA). We found that aging CB2^-/- mice have an increased incidence of spontaneous cancerous and precancerous skin lesions compared to their WT counterparts. In the DMBA/TPA model, CB2^-/- developed more and larger papillomas, had decreased spontaneous regression of papillomas, and displayed an altered systemic immune profile, including upregulated CD4+ T cells and dendritic cells, compared to WT mice. Immune cell infiltration in the tumor microenvironment was generally low for both genotypes, although a trend of higher myeloid-derived suppressor cells was observed in the CB2^-/- mice. CB2 expression in carcinogen-exposed skin was significantly higher compared to naïve skin in WT mice, suggesting a role of CB2 on keratinocytes. Taken together, our data show that endogenous CB2 activation plays an anti-tumorigenic role in non-melanoma skin carcinogenesis, potentially via an immune-mediated response involving the alteration of T cells and myeloid cells coupled with the modulation of keratinocyte activity.

Molecular Alterations in Cutaneous Squamous Cell Carcinoma in Immunocompetent and Immunosuppressed Hosts-A Systematic Review

The characterization of cutaneous squamous cell carcinoma (cSCC) at the molecular level is lacking in the current literature due to the high mutational burden of this disease. Immunosuppressed patients afflicted with cSCC experience considerable morbidity and mortality. In this article, we review the molecular profile of cSCC among the immunosuppressed and immunocompetent populations at the genetic, epigenetic, transcriptomic, and proteometabolomic levels, as well as describing key differences in the tumor immune microenvironment between these two populations. We feature novel biomarkers from the recent literature which may serve as potential targets for therapy.

Review: PD-L1 as an emerging target in the treatment and prevention of keratinocytic skin cancer

Recent advances in the understanding and targeting of immune checkpoints have led to great progress in immune therapies against many forms of cancer. While many types of immune checkpoints are currently targeted in the clinic, this review will focus on recent research implicating the programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) axis as an emerging focus for the treatment of keratinocytic tumors. PD-L1 is of particular interest in nonmelanoma skin cancer (NMSC), as it is not only upregulated in these tumors but is stimulated by environmental ultraviolet exposure. This response may also make PD-L1 an excellent target for photochemoprevention using topically applied small molecule inhibitors. Here, we summarize recent investigations on PD-L1 expression and clinically relevant immune checkpoint inhibitor treatment in cutaneous squamous cell carcinoma, basal cell carcinoma, and head and neck squamous cell carcinoma, as well as small molecule agents targeting PD-L1 that may be useful for clinical development aiming at treatment or prevention of NMSC.

Compromised T Cell Immunity Links Increased Cutaneous Papillomavirus Activity to Squamous Cell Carcinoma Risk

Cutaneous squamous cell carcinoma (cSCC) is the second most common cancer, with increased incidence in immunosuppressed patients. β-Human papillomavirus has been proposed as a contributor to cSCC risk partly on the basis of increased β-human papillomavirus viral load and seropositivity observed among patients with cSCC. Experimental data in mice colonized with mouse papillomavirus type 1 suggest that T cell immunity against β-human papillomavirus suppresses skin cancer in immunocompetent hosts, and the loss of this immunity leads to the increased risk of cSCC. In this study, we show that CD8⁺ T cell depletion in mouse papillomavirus type 1‒colonized mice that underwent skin carcinogenesis protocol led to increased viral load in the skin and seropositivity for anti‒mouse papillomavirus type 1 antibodies. These findings provide evidence that compromised T cell immunity can be the link that connects increased β-human papillomavirus detection to cSCC risk.

Coexistence of Cutaneous Squamous Cell Carcinoma and Basal Cell Carcinoma in a Renal Transplant Recipient: A Case Report

In solid organ transplant patients, non-melanoma skin cancer remains a leading cause of mortality. The most common skin malignancies in solid organ transplant patients are squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). In organ transplant patients, SCC is 100 times more prevalent, and BCC is 10 times more prevalent than in the general population. Many risk factors for developing such malignancies are equivalent to those in the general population. However, in the transplant population, such cancers occur at an earlier age, act more aggressively, and often appear at multiple locations. Thus, assiduousness on the patient's part and healthcare providers is the highest priority. The concurrence of SCC and BCC together is rarely encountered in a post-transplant individual. We report a rare case of coexistence of SCC and BCC in the same patient. A 63-year-old man had been diagnosed with SCC and BCC simultaneously by a punch biopsy performed at two different scalp lesions of different diameters. This review describes an unusual occurrence of both skin cancers concurrently in a kidney transplant recipient.

Transcriptome-Guided Drug Repurposing for Aggressive SCCs

Despite a significant rise in the incidence of cutaneous squamous cell carcinoma (SCC) in recent years, most SCCs are well treatable. However, against the background of pre-existing risk factors such as immunosuppression upon organ transplantation, or conditions such as recessive dystrophic epidermolysis bullosa (RDEB), SCCs arise more frequently and follow a particularly aggressive course. Notably, such SCC types display molecular similarities, despite their differing etiologies. We leveraged the similarities in transcriptomes between tumors from organ transplant recipients and RDEB-patients, augmented with data from more common head and neck (HN)-SCCs, to identify drugs that can be repurposed to treat these SCCs. The in silico approach used is based on the assumption that SCC-derived transcriptome profiles reflect critical tumor pathways that, if reversed towards healthy tissue, will attenuate the malignant phenotype. We determined tumor-specific signatures based on differentially expressed genes, which were then used to mine drug-perturbation data. By leveraging recent efforts in the systematic profiling and cataloguing of thousands of small molecule compounds, we identified drugs including selumetinib that specifically target key molecules within the MEK signaling cascade, representing candidates with the potential to be effective in the treatment of these rare and aggressive SCCs.

The Correlation Between Immunohistochemistry Findings and Metastasis in Squamous Cell Carcinoma: A Review

BACKGROUND

Cutaneous squamous cell carcinoma (SCC) is the second most common type of skin cancer. Only 2% to 5% of SCCs metastasize; however, those do carry a poor prognosis. Immunohistochemistry (IHC) is widely used by pathologists to characterize skin cancers and provide clinically useful information.

OBJECTIVE

To evaluate the potential prognostic associations between IHC findings and metastasis in SCC.

METHODS

Searches were conducted in MEDLINE via PubMed for articles published between 1999 and 2019. Search criteria included key words "immunohistochemistry" and "cutaneous squamous cell carcinoma." Six hundred and fifty-three articles were returned and screened, which ultimately left 31 for inclusion in our manuscript.

RESULTS

Thirty-one articles analyzed in this review included a discussion of the expression of a particular IHC marker and the associated risk of metastasis and/or clinical utility of IHC markers in SCC, especially metastatic SCC. Markers that had several or more studies supporting clinical utility were E-cadherin, podoplanin, CD8+ T cells, PD-L1, epidermal growth factor receptor, and Cyclin D1.

CONCLUSION

Immunohistochemistry profiling of SCC may be useful in select cases when providing a prognosis remains challenging and in identification of potential therapeutic targets for high-risk or metastatic tumors.

The contribution of human papilloma virus infection to cutaneous squamous cell carcinoma in patients with chronic lymphocytic leukemia

Patients with chronic lymphocytic leukemia (CLL), a B-cell malignancy characterized by impaired humoral and cellular immunity, are at increased risk of developing cutaneous squamous cell carcinoma (cSCC). Human papilloma virus (HPV) is the most common sexually transmitted infection worldwide and it has been associated with various malignancies, including cSCC. Impaired cell-mediated immunity is considered a primary risk factor in HPV-induced cSCC. We examined cSCC lesions from CLL patients with consensus review and HPV genetic analysis to further characterize the relationship between HPV and prevalence of cutaneous malignancy in this population. Eleven patients with CLL contributed 35 cSCCs. Treatment with chemotherapy shortened the latency time to first cSCC. HPV was detected in 54% of the lesions. Among the HPV-positive cSCC lesions, 84% of the lesions contained alpha-genus HPV, 42% contained beta-genus HPV, and 26% of the lesions contained both genera. There was a significant association between HPV-containing lesions and peritumoral lymphocytic inflammation, suggesting this as a future area for further characterization. The majority of the lesions, including those with alpha-genus HPV, occurred in sun-exposed areas, such as the scalp and face. These findings may lead to practice-changing recommendations for skin cancer, including the use of vaccinations to reduce HPV-associated skin cancer.

IFN-γ Critically Enables the Intratumoural Infiltration of CXCR3+ CD8+ T Cells to Drive Squamous Cell Carcinoma Regression

Simple Summary

Cutaneous squamous cell carcinoma (SCC) is prevalent in aged individuals and individuals with compromised or weakened immune systems, indicating a close association between immune function and SCC control. The aim of our study was to uncover the identity of key immune subsets that mediate SCC control, and to elucidate the mechanistic role of the proinflammatory cytokine Interferon-gamma in this process. We established a SCC regressor model, which we used to determine that: (1) CD8⁺ T cells, not CD4⁺ T cells or NK cells, are essential for SCC regression; (2) the neutralisation of Interferon-gamma prevents CD8⁺ T cell infiltration and SCC regression; (3) CD8⁺ T cell migration into SCC critically depends upon Interferon-gamma-induced chemokine expression. Thus, our model can be used to understand the key immune mechanisms involved in SCC regression, which will support targeted investigations into the integrity of these mechanisms in patients with progressive disease.

Abstract

Ultraviolet (UV) radiation-induced tumours carry a high mutational load, are highly immunogenic, and often fail to grow when transplanted into normal, syngeneic mice. The aim of this study was to investigate factors critical for the immune-mediated rejection of cutaneous squamous cell carcinoma (SCC). In our rejection model, transplanted SCC establish and grow in mice immunosuppressed with tacrolimus. When tacrolimus is withdrawn, established SCC tumours subsequently undergo immune-mediated tumour rejection. Through the depletion of individual immune subsets at the time of tacrolimus withdrawal, we established a critical role for CD8⁺ T cells, but not CD4⁺ T cells, γδ T cells, or NK cells, in driving the regression of SCC. Regression was critically dependent on IFN-γ, although IFN-γ was not directly cytotoxic to SCC cells. IFN-γ-neutralisation abrogated SCC regression, significantly reduced CD8⁺ T cell-infiltration into SCC, and significantly impaired the secretion of CXCL9, CXCL10 and CCL5 within the tumour microenvironment. A strong positive correlation was revealed between CXCL10 expression and CD8⁺ T cell abundance in tumours. Indeed, blockade of the CXCL10 receptor CXCR3 at the time of tacrolimus withdrawal prevented CD8⁺ T cell infiltration and the regression of SCC. Chimeric models revealed an important role for immune cells as producers of IFN-γ, but not as recipients of IFN-γ signals via the IFN-γ receptor. Together, these findings suggest a key role for IFN-γ in driving the expression of chemokines within the tumour environment essential for the destruction of established SCC by CD8⁺ T cells.

Low-Dose Acitretin for Secondary Prevention of Keratinocyte Carcinomas in Solid-Organ Transplant Recipients

BACKGROUND

Keratinocyte carcinomas, particularly squamous cell carcinoma (SCC), occur more frequently and aggressively in solid-organ transplant recipients (SOTRs) than in the general population. Systemic retinoids are effective in secondary prevention of keratinocyte carcinomas in this population, but their use is limited by adverse effects including a rebound effect in cases of treatment discontinuation.

OBJECTIVE

Our aim was to determine whether low-dose acitretin is efficient in the secondary prevention of keratinocyte carcinomas in SOTRs.

METHODS

This retrospective case-crossover study was conducted at a specialized dermatology clinic for SOTRs in a large transplantation center in 2010-2017. Patients with at least 1 previous keratinocyte carcinoma who were treated with acitretin 10 mg/day for 2 years were included. The main outcome was the difference in the number of new keratinocyte carcinomas diagnosed during treatment compared to during the 2-year pretreatment period.

RESULTS

The cohort included 34 SOTRs. A significant reduction in the mean number of new keratinocyte carcinomas during treatment relative to the pretreatment period was observed (1.7 vs. 3.6, -53% p = 0.002). Similar results were noted on analysis by tumor type, for both SCC and basal cell carcinoma.

CONCLUSION

This study of SOTRs demonstrated positive results for low-dose acitretin as a chemoprevention of keratinocyte carcinomas in this population.

Skin cancer in non-white liver transplant recipients: Mayo Clinic experience

BACKGROUND

Limited data are available on the development of skin cancer and the associated risk factors for non-White liver transplant (LT) recipients. The aim of this study is to determine the incidence of newly diagnosed skin cancer postoperatively and to identify the risk factors for the development of skin cancer in non-White LT recipients.

METHODS

We conducted an initial retrospective chart review of non-White LT patients who received a transplant at our center between January 1, 2011, and December 31, 2013.

RESULTS

Of the 96 patients in the study cohort, 32% were Black, 17% were Asian, 15% were White Hispanic, and 10% were Black Hispanic. One patient had a history of nonmelanoma skin cancer before transplant. No skin cancers were diagnosed during follow-up (median, 1.3 years; range, 17 days to 8.6 years).

CONCLUSION

Our center's experience is consistent with the literature and suggests that the incidence of newly diagnosed skin cancer in non-White liver transplant recipients is low. Longer follow-up may provide additional insights into the specific risk factors for the posttransplant development of skin cancer.

Nonsurgical treatment of skin cancer with local delivery of bioadhesive nanoparticles

Keratinocyte-derived carcinomas, including squamous cell carcinoma (SCC), comprise the most common malignancies. Surgical excision is the therapeutic standard but is not always clinically feasible, and currently available alternatives are limited to superficial tumors. To address the need for a nonsurgical treatment for nodular skin cancers like SCC, we developed a bioadhesive nanoparticle (BNP) drug delivery system composed of biodegradable polymer, poly(lactic acid)-hyperbranched polyglycerol (PLA-HPG), encapsulating camptothecin (CPT). Nanoparticles (NPs) of PLA-HPG are nonadhesive NPs (NNPs), which are stealthy in their native state, but we have previously shown that conversion of the vicinal diols of HPG to aldehydes conferred NPs the ability to form strong covalent bonds with amine-rich surfaces. Herein, we show that these BNPs have significantly enhanced binding to SCC tumor cell surfaces and matrix proteins, thereby significantly enhancing the therapeutic efficacy of intratumoral drug delivery. Tumor injection of BNP-CPT resulted in tumor retention of CPT at ∼50% at 10 d postinjection, while CPT was undetectable in NNP-CPT or free (intralipid) CPT-injected tumors at that time. BNP-CPT also significantly reduced tumor burden, with a portion (∼20%) of BNP-CPT-treated established tumors showing histologic cure. Larger, more fully established PDV SCC tumors treated with a combination of BNP-CPT and immunostimulating CpG oligodeoxynucleotides exhibited enhanced survival relative to controls, revealing the potential for BNP delivery to be used along with local tumor immunotherapy. Taken together, these results indicate that percutaneous delivery of a chemotherapeutic agent via BNPs, with or without adjuvant immunostimulation, represents a viable, nonsurgical alternative for treating cutaneous malignancy.

Spontaneous regression of squamous cell carcinoma in the setting of dental infection and needle biopsy

To our knowledge, this is the first reported case of spontaneous regression of squamous cell carcinoma within a lymph node. We speculate that prior dental infection, fever, and biopsy incited an antitumor immune reaction.

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.

Multiple nonmelanocytic skin cancers in multiple regions

The most common forms of nonmelanocytic skin cancer (NMSC) are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). The growing incidence of skin cancer in the Republic of Korea has sparked increasing scientific interest in these types of tumors. In the case described herein, multiple NMSCs occurred asynchronously in various areas of the body in a single patient. A 67-year-old man presented with an ulcerative lesion on the right retro-auricle and multiple keratinized masses on the back and face. The right retro-auricular lesion was diagnosed as BCC, and the keratinized masses on the patient’s back and face were diagnosed as SCC. He subsequently presented with numerous pigmented skin lesions on the forehead, temple, pre-auricle, neck, right forearm, right hand, and both thighs. One lesion on the neck was diagnosed as BCC, and five lesions on the right hand and forearm were diagnosed as SCC. The patient was also diagnosed with supraglottic SCC and external auditory canal SCC. An otolaryngologist performed radical excision of the primary SCC. Suspected skin cancer lesions observed on the face and both ears were diagnosed as SCC. Patients with multiple NMSCs are at an elevated risk for additional skin cancers, making periodic follow-up important; furthermore, all suspicious lesions should be biopsied.

Treatment approaches in immunosuppressed patients with advanced cutaneous squamous cell carcinoma

Immunosuppression, both iatrogenic and disease-related, is associated with a greatly increased incidence of cutaneous SCC (cSCC) and with aggressive cSCC and worse disease outcomes. Consequently, rapid access to skin cancer services and prudent surgical choices, such as circumferential margin assessment, is essential when treating advanced cSCC in an immunosuppressed patient. For high-risk cancers and control of cSCC multiplicity, additional strategies should be actively considered within the multidisciplinary clinical care team. These include minimization or revision of immunosuppressive medications, systemic chemoprevention (including retinoids, nicotinamide, capecitabine) and adjuvant therapies such as radiotherapy. Unfortunately, there is a relative paucity of good evidence for many of these treatments in the immunosuppressed. Systemic treatments for metastatic cSCC are often contraindicated in organ transplant recipients, notably checkpoint inhibitor immunotherapy. There are also toxicity concerns with some conventional chemotherapies and EGFR inhibitors. Until recently, clinical trials have largely excluded immunosuppressed individuals. Development of more effective treatment for advanced cSCC in this high-risk group and prospective clinical trials are now research priorities.

Surveyed dermatologists are less likely to curette invasive squamous cell carcinoma in solid organ transplant recipients

Background

The risk of squamous cell carcinoma (SCC) is increased in solid organ transplant recipients (OTRs), and preferential treatment modalities vary among clinicians.

Objectives

The purpose of this study was to survey dermatologists regarding practice patterns for electrodesiccation and curettage (EDC) of SCC in OTRs and nontransplant patients.

Methods

An 18-question survey was sent to dermatologist members of the International Transplant Skin Cancer Collaborative, Association of Professors of Dermatology, and American College of Mohs Surgery. Differences in EDC practice patterns for treatment of SCC in OTRs and nontransplant patients were evaluated.

Results

Dermatologists in this study (N = 227) were more likely to treat SCC with EDC in nontransplant patients (67.4%) than in OTRs (48.0%; P = .0003).

Dermatologists who perform EDC in both groups (n = 108) were unlikely to use EDC on the H-zone of the face; they were more likely to EDC tumors on non-H-zone areas of the face and neck in nontransplant patients compared to OTRs (P = .0007). Dermatologists were more likely to use EDC over surgery in nontransplant patients compared to OTRs with the following demographics: dementia or psychiatric disease (P = .04), multiple medical comorbidities (P = .03), or anticoagulation medications (P = .02).

Conclusions

In OTRs with SCC, 48% of clinicians would consider EDC. The main factors that affect the decision to perform EDC include tumor location and patient comorbidities.

Risk factors for recurrence in cutaneous squamous cell carcinoma after Mohs micrographic surgery: A retrospective review of 237 Asian patients

Even after complete removal with Mohs micrographic surgery (MMS), cutaneous squamous cell carcinoma (cSCC) may recur; however, information about risk factors for recurrence in Asian patients is limited. This retrospective study reviewed cSCC patients treated with MMS at a single tertiary referral center from 2000 to 2017. Two hundred and thirty-seven patients were included and 36 showed recurrence (20 with local recurrence, 16 with distant metastasis). History of organ transplantation, diabetes, other malignancies and poorly differentiated histology correlated with cSCC recurrence. History of organ transplantation and cryotherapy at the cSCC site were related to higher local recurrence rates, and poor differentiation related to higher distant metastasis in Asian cSCC patients treated with MMS.

Immunity to commensal papillomaviruses protects against skin cancer

Immunosuppression increases the risk of cancers associated with viral infection¹. In particular, squamous cell carcinoma (SCC) of the skin has a >100-fold increased risk in immunosuppressed patients and has been associated with beta human papillomavirus (β-HPV) infection^2–4. Previous studies, however, have failed to establish a causative role for HPVs in driving skin cancer development. Herein, we provide an alternative explanation for this association by demonstrating that the T cell immunity against commensal papillomaviruses suppresses skin cancer in immunocompetent hosts. The loss of this immunity, rather than the oncogenic effect of HPVs, is the reason for the markedly increased risk of skin cancer in immunosuppressed patients. To investigate the impact of papillomavirus on carcinogen-driven skin cancer, we colonized several strains of immunocompetent mice with mouse papillomavirus type 1 (MmuPV1)⁵. Mice with natural anti-MmuPV1 immunity after colonization and acquired immunity due to T cell transfer from immune mice or MmuPV1 vaccination were protected against chemical- and ultraviolet (UV)-induced skin carcinogenesis in a CD8⁺ T cell-dependent manner. RNA and DNA in situ hybridizations for 25 commensal β-HPVs revealed a significant reduction in viral activity and load in human skin cancer compared to the adjacent normal skin, suggesting a strong immune selection against virus-positive malignant cells. Consistently, β-HPV E7 peptides activated CD8⁺ T cells from normal human skin. Our findings reveal a beneficial role for commensal viruses and establish the foundation for novel immune-based approaches to block skin cancer development by boosting immunity against the commensal HPVs present in all of our skin.

Primary squamous cell carcinoma of the peristomal skin of gastrostomy in a transplant patient: a first case report

Gastrostomy is commonly used to provide enteral nutrition when patient require a nutrition support due to not enough oral eating. Gastrostomy tube can lead to many complications; squamous cell carcinoma (SCC) is an extremely rare complication of the site of gastrostomy, it was described after several years of enteral nutrition or as part of a metastasis of head and neck tumors. We describe the case of a 60-year-old man heart-liver transplanted for hereditary amyloidosis. He required the setting of a gastrostomy-tube for enteral feeding and developed after only 18 months a SCC on the site of gastrostomy confirmed in the histologic report. The increased risk of SCC in transplant patients is due to immunosuppressive therapies, even though everolimus could reduce this risk. The pose of a gastrostomy is responsible of a chronic cutaneous inflammation, which is another risk factor for SCC. In these immunocompromised patients, gastrostomy or other chronic skin injury requires special monitoring, especially if the wound does not heal.

TLR4 in skin cancer: From molecular mechanisms to clinical interventions

The health and economic burden imposed by skin cancer is substantial, creating an urgent need for the development of improved molecular strategies for its prevention and treatment. Cutaneous exposure to solar ultraviolet (UV) radiation is a causative factor in skin carcinogenesis, and TLR4-dependent inflammatory dysregulation is an emerging key mechanism underlying detrimental effects of acute and chronic UV exposure. Direct and indirect TLR4 activation, upstream of inflammatory signaling, is elicited by a variety of stimuli, including pathogen-associated molecular patterns (such as lipopolysaccharide) and damage-associated molecular patterns (such as HMGB1) that are formed upon exposure to environmental stressors, such as solar UV. TLR4 involvement has now been implicated in major types of skin malignancies, including nonmelanoma skin cancer, melanoma and Merkel cell carcinoma. Targeted molecular interventions that positively or negatively modulate TLR4 signaling have shown promise in translational, preclinical, and clinical investigations that may benefit skin cancer patients in the near future.

Advances in the Understanding of Skin Cancer: Ultraviolet Radiation, Mutations, and Antisense Oligonucleotides as Anticancer Drugs

Skin cancer has always been and remains the leader among all tumors in terms of occurrence. One of the main factors responsible for skin cancer, natural and artificial UV radiation, causes the mutations that transform healthy cells into cancer cells. These mutations inactivate apoptosis, an event required to avoid the malignant transformation of healthy cells. Among these deadliest of cancers, melanoma and its 'younger sister', Merkel cell carcinoma, are the most lethal. The heavy toll of skin cancers stems from their rapid progression and the fact that they metastasize easily. Added to this is the difficulty in determining reliable margins when excising tumors and the lack of effective chemotherapy. Possibly the biggest problem posed by skin cancer is reliably detecting the extent to which cancer cells have spread throughout the body. The initial tumor is visible and can be removed, whereas metastases are invisible to the naked eye and much harder to eliminate. In our opinion, antisense oligonucleotides, which can be used in the form of targeted ointments, provide real hope as a treatment that will eliminate cancer cells near the tumor focus both before and after surgery.

Type of Organ Transplanted Impacts the Risk and Presentation of Cutaneous Squamous Cell Carcinoma in Transplant Recipients

OBJECTIVES

Transplant immunosuppression increases the risk of cutaneous squamous cell carcinoma by 65- to 200-fold. Our objective was to investigate the impact of the type of organ transplanted on the risk and presentation of cutaneous squamous cell carcinoma.

MATERIALS AND METHODS

The retrospective database of the Duke University Health System was queried to identify patients who underwent an organ transplant from 1996 to 2016. Data regarding transplant outcomes, cutaneous squamous cell carcinoma, immunosuppressive regimens, and survival were recorded. We used chi-square tests, analysis of variance, and unpaired t tests to compare the incidence and presentation of cutaneous squamous cell carcinoma among organ types.

RESULTS

Of 3652 renal, hepatic, and cardiothoracic transplant patients identified, 142 patients developed at least 1 cutaneous squamous cell carcinoma. The incidence of cutaneous squamous cell carcinoma varied by type of organ transplanted, with 46 of 1684 (2.7%) renal transplant patients developing cutaneous squamous cell carcinoma, 33 of 804 (4.1%) hepatic transplant patients, and 63 of 1164 (5.4%) cardiothoracic transplant patients over the median follow-up time of 6.5 years. Incidence in the renal transplant versus the cardiothoracic transplant group was significantly different (P < .001). The time to presentation of cutaneous squamous cell carcinoma varied significantly by group, with the renal cohort presenting at 3.8 years compared with at 2.4 years in the cardiothoracic group and 2.1 years in the hepatic group (P < .001).

CONCLUSIONS

The type of organ transplanted confers a unique risk and presentation of cutaneous squamous cell carcinoma.

Comparison of Skin Cancer Incidence in Caucasian and Non-Caucasian Liver Vs. Lung Transplant Recipients: A Tale of Two Regimens

BACKGROUND

Organ transplantation is a significant risk factor for the development of skin cancer. The impact of skin type, immunosuppressive regimens, and photosensitizing agents requires further study.

OBJECTIVE

The objective of this study was to compare skin cancer development between Caucasian and non-Caucasian transplant recipients at the University of Southern California.

METHODS

We performed a retrospective chart review of lung and liver transplantations to determine the incidence of post-transplant skin cancer. Participants included patients who underwent lung or liver transplantation between 2005 and 2013 at our institution. Patients included in the study were limited to those who survived through the study observation period.

RESULTS

We analyzed 475 patients who underwent transplantation, including 370 liver transplant recipients and 105 lung transplant recipients. Among these, 46.3% identified as Caucasian, while 53.7% were non-Caucasian. Over a mean follow-up of 7.9 years, 11.8% of Caucasian patients developed at least one skin cancer, compared with 2.7% of non-Caucasians (p < 0.001). However, irrespective of race, skin cancer development was significantly greater in lung compared with liver transplant recipients (20.0% vs. 3.2%, p < 0.001). The standard immunosuppressive and prophylactic regimens were mycophenolate mofetil and tacrolimus based for both transplants. Mycophenolate mofetil was maintained throughout the course in lung transplant patients, whereas this agent was reduced and terminated when possible in liver transplant recipients. In addition, during the years examined, voriconazole, a known photosensitizing agent, was used in lung transplant recipients to prevent aspergillosis.

CONCLUSIONS

Fair skin type increases post-transplant skin cancer development, irrespective of the immunosuppressive regimen. A higher risk of skin cancer is associated with different regimens; in particular photosensitizing agents may increase risk in transplant recipients.

Bacillus anthracis Protective Antigen Shows High Specificity for a UV Induced Mouse Model of Cutaneous Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) accounts for the majority of non-melanoma skin cancer related deaths, particularly in immunosuppressed persons. Identification of biomarkers that could be used to identify or treat SCC would be of significant benefit. The anthrax toxin receptors, Tumor Endothelial Marker 8 (TEM8) and Capillary Morphogenesis Gene 2 (CMG2), are endothelial receptors involved in extracellular matrix homeostasis and angiogenesis that are selectively upregulated on numerous tumors. One method of targeting these receptors is Protective Antigen (PA), a protein produced by B. anthracis that mediates binding and translocation of anthrax toxins into cells. PA targeted toxins have been demonstrated to selectively inhibit tumor growth and angiogenesis, but tumor selectivity of PA is currently unknown. In this work fluorescently labeled PA was shown to maintain receptor dependent binding and internalization in vitro. Utilizing a human papillomavirus transgenic mouse model that develops cutaneous SCC in response to ultraviolet irradiation we identified tumor uptake of PA in vivo. The intravenously administered PA resulted in tumor specific localization, with exclusive tumor detection 24 h post injection. Ex vivo analysis identified significantly higher fluorescence in the tumor compared to adjacent healthy tissue and major clearance organs, demonstrating low non-specific uptake and rapid clearance. While both TEM8 and CMG2 were observed to be overexpressed in SCC tumor sections compared to control skin, the intravenously administered PA was primarily co-localized with TEM8. These results suggest that PA could be systemically administered for rapid identification of cutaneous SCC, with potential for further therapeutic development.

Skin Cancer-Sun Knowledge and Sun Protection Behaviors of Liver Transplant Recipients in Turkey

The aim of this study was to compare liver transplant recipients (LTRs) with the general population regarding their knowledge of skin cancer, sun health, sun protection behaviors, and affecting factors. This cross-sectional study was conducted in Turkey between March 2016 and September 2016 with 104 LTRs and 100 participants from the general population group (GPG). The mean age of the LTRs was 53.2 ± 11.8 and that of the GPG was 42.7 ± 14.5. The LTRs' skin cancer and sun knowledge were significantly lower than in the GPG, but there was no difference between the two groups in terms of their sun protection behavior scores. The most commonly used sun protection behaviors of LTRs were not being outside and not sunbathing between 10 a.m. and 4 p.m., wearing clothing that covers the skin, and avoiding the solarium. Behaviors commonly practiced by the GPG were wearing sunglasses, wearing sunscreen with a sun protection factor of 15 or higher before going outside, wearing sunscreen at the beach, while swimming or doing physical activity outside, and reapplying it every 2 h. Results of our study will contribute to the development of education and training programs for LTRs on skin cancer. The results also demonstrated the importance of practicing adequate sun protection behaviors which will certainly impact their future health.

TLR4-directed Molecular Strategies Targeting Skin Photodamage and Carcinogenesis

Background:

Exposure to solar ultraviolet (UV) radiation is a causative factor in skin photodamage and carcinogenesis, and inflammatory dysregulation is a key mechanism underlying detrimental effects of acute and chronic UV exposure. The health and economic burden of skin cancer treatment is substantial, creating an increasingly urgent need for the development of improved molecular strategies for photoprotection and photochemoprevention.

Methods:

A structured search of bibliographic databases for peer-reviewed research literature revealed 139 articles including our own that are presented and critically evaluated in this TLR4-directed review.

Objective:

To understand the molecular role of Toll-like receptor 4 (TLR4) as a key regulator of skin anti-microbial defense, wound healing, and cutaneous tumorigenic inflammation. The specific focus of this review is on recent published evidence suggesting that TLR4 represents a novel molecular target for skin photoprotection and cancer photochemoprevention.

Results:

Cumulative experimental evidence indicates that pharmacological and genetic antagonism of TLR4 suppresses UV-induced inflammatory signaling involving the attenuation of cutaneous NF-κB and AP-1 stress signaling observable in vitro and in vivo. TLR4-directed small molecule pharmacological antagonists [including eritoran, (+)-naloxone, ST2825, and resatorvid] have now been identified as a novel class of molecular therapeutics. TLR4 antagonists are in various stages of preclinical and clinical development for the modulation of dysregulated TLR4-dependent inflammatory signaling that may also contribute to skin photodamage and photocarcinogenesis in human populations.

Conclusion:

Future research should explore the skin photoprotective and photochemopreventive efficacy of topical TLR4 antagonism if employed in conjunction with other molecular strategies including sunscreens.

Human oncoviruses: Mucocutaneous manifestations, pathogenesis, therapeutics, and prevention: Papillomaviruses and Merkel cell polyomavirus

In 1964, the first human oncovirus, Epstein-Barr virus, was identified in Burkitt lymphoma cells. Since then, 6 other human oncoviruses have been identified: human papillomavirus, Merkel cell polyomavirus, hepatitis B and C viruses, human T-cell lymphotropic virus-1, and human herpesvirus-8. These viruses are causally linked to 12% of all cancers, many of which have mucocutaneous manifestations. In addition, oncoviruses are associated with multiple benign mucocutaneous diseases. Research regarding the pathogenic mechanisms of oncoviruses and virus-specific treatment and prevention is rapidly evolving. Preventative vaccines for human papillomavirus and hepatitis B virus are already available. This review discusses the mucocutaneous manifestations, pathogenesis, diagnosis, treatment, and prevention of oncovirus-related diseases. The first article in this continuing medical education series focuses on diseases associated with human papillomavirus and Merkel cell polyomavirus, while the second article in the series focuses on diseases associated with hepatitis B and C viruses, human T-cell lymphotropic virus-1, human herpesvirus-8, and Epstein-Barr virus.

MicroRNA-340 inhibits squamous cell carcinoma cell proliferation, migration and invasion by downregulating RhoA

BACKGROUND

MicroRNAs are reported to play an important role in tumor growth and metastasis, including squamous cell carcinoma (SCC). Accumulative evidence has revealed that dysregulated miR-340 expression contributed to the carcinogenesis and development of various cancers.

OBJECTIVE

The aim of the current study was to investigate the role and the underlying mechanism of miR-340 in SCC cell proliferation, migration and invasion.

METHODS

Quantitative real-time PCR was performed to examine the expression of miR-340 in SCC tissues and cell lines. The function of miR-340 in SCC was investigated through Cell Counting Kit-8, wound healing, transwell migration and invasion assays. Bioinformatics analysis, luciferase reporter assay, western blotting and immunohistochemical analysis were conducted to predict and confirm the target gene of miR-340.

RESULTS

In the present study, we first found that miR-340 was significantly decreased in both SCC tissues and cell lines. Moreover, ectopic expression of miR-340 remarkably attenuated SCC cell proliferation, migration and invasion, whereas inhibition of endogenous miR-340 promoted SCC cell proliferation, migration and invasion in vitro. Our subsequent bioinformatics analysis and luciferase reporter assay showed that RhoA was a novel direct target of miR-340 in SCC cells, and the knockdown of RhoA expression rescued the effects of miR-340 inhibition on SCC cell proliferation, migration and invasion. More importantly, the expression of RhoA and miR-340 was negatively correlated in SCC tissues.

CONCLUSION

Our findings demonstrate the tumor suppressor role of miR-340 in SCC by directly regulating RhoA. Therefore, restoration of miR-340 expression can be a potential therapeutic approach for SCC treatment.

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.

Chronic Inflammation Promotes Skin Carcinogenesis in Cancer-Prone Discoid Lupus Erythematosus

High-risk skin cancer is a rare, but severe, complication associated with discoid lupus erythematosus (DLE). Chronic scar, inflammation, UVR, and immunosuppressive medications are proposed explanations for this heightened skin cancer risk; however, the exact mechanism driving skin carcinogenesis in DLE is unknown. The distinct co-localization of multiple independent skin cancers with areas of active inflammation in two DLE patients followed over 8 years strongly suggested that lupus inflammation promotes skin carcinogenesis in DLE. To investigate this clinical observation, we subjected lupus-prone MRL/lpr and control (MRL/n) mice to a skin carcinogenesis protocol. Skin tumors developed preferentially within the cutaneous lupus inflammation without scarring in MRL/lpr mice (P < 0.01). The inflammation in MRL/lpr skin was characterized by the accumulation of regulatory T cells, mast cells, M2 macrophages, and markedly elevated transforming growth factor-β1 and IL-6 levels, which have been linked to tumor promotion. Tacrolimus treatment reduced skin inflammation and blocked cancer development in MRL/lpr mice (P = 0.0195). A similar tumor-promoting immune environment was detected in SCCs and the perilesional skin of cancer-prone DLE patients. Therefore, discoid lupus inflammation promotes skin cancer in high-risk DLE patients, and blocking the inflammation may be critical for preventing this life-threatening complication of DLE.

The impact of transplant rejection on cutaneous squamous cell carcinoma in renal transplant recipients

BACKGROUND

The incidence of cutaneous squamous cell carcinoma (cSCC) is markedly increased in renal transplant recipients compared with that of the nontransplant population.

AIM

To investigate whether there is a relationship between transplant rejection and cSCC.

METHODS

The Duke Enterprise Data Unified Content Explorer historical database was used to identify patients who had undergone a renal transplant at Duke University Hospital during a 20-year period. Data on patient demographics, transplant dates, first rejection episodes, first cSCC development, medication, laboratory results and survival were recorded.

RESULTS

In total, 1684 patients were identified, of whom 126 (7.5%) experienced an episode of rejection and 46 (4.0%) developed a cSCC after transplant. The incidence of cSCC was significantly greater in the rejection group, with 8.7% of patients developing cSCC compared with 2.2% in the no-rejection group (P < 0.001). Median lag time to cSCC was shorter in the rejection group (2.5 years; age 0.4-9.0 years) than the no-rejection group (4.2 years; range 1.3-20.4 years) (P < 0.03).

CONCLUSIONS

Transplant rejection is associated with both a higher incidence and an accelerated time course for development of cSCC following renal transplantation. Close dermatological surveillance should be considered following an episode of rejection in this patient population.