Progress in Dermatology

Immunity against Non-Melanoma Skin Cancer and the Effect of Immunosuppressive Medication on Non-Melanoma Skin Cancer Risk in Solid Organ Transplant Recipients

Non-melanoma skin cancers (NMSCs) occur frequently in the Caucasian population and are considered a burden for health care. Risk factors include ultraviolet (UV) radiation, ethnicity and immunosuppression. The incidence of NMSC is significantly higher in solid organ transplant recipients (SOTRs) than in immunocompetent individuals, due to immunosuppressive medication use by SOTRs. While the immunosuppressive agents, calcineurin inhibitors and purine analogues increase the incidence of NMSC in transplant recipients, mTOR inhibitors do not. This is most likely due to the different immunological pathways that are inhibited by each class of drug. This review will focus on what is currently known about the immune response against cutaneous squamous cell carcinoma (cSCC) and basal cell carcinoma (BCC), two of the main types of NMSC. Furthermore, we will describe the different classes of immunosuppressants given to SOTRs, which part of the immune system they target and how they can contribute to NMSC development. The risk of developing NMSC in SOTRs is the result of a combination of inhibiting immunological pathways involved in immunosurveillance against NMSC and the direct (pro/anti) tumor effects of immunosuppressants.

Patterns of photoprotective behavior, cumulative sun-exposure and skin cancer risk among solid organ transplant recipients: a dermatology transplant clinic experience

BACKGROUND

The risk for keratinocyte cancer is dramatically increased in solid organ transplant recipients (OTR) with a first post-transplant keratinocyte cancer conferring a high risk for subsequent keratinocyte cancer arising with accelerated dynamics. Despite cumulative ultraviolet radiation (UVR) being the primary responsible environmental carcinogen reduced compliance with photoprotective measures among OTR has been reported. Risk assessment tools could help guide clinical decision-making and targeted prevention strategies for patients at particularly high risk for post-transplant keratinocyte cancer.

OBJECTIVES

To evaluate cumulative sun exposure by means of an assigned total sun burden (TSB) score, sunscreen use and associated risk factors for keratinocyte cancer in the post-transplantation phase of OTR.

METHODS

A retrospective single-center cohort study analyzing medical records and standardized questionnaires of 290 OTR cared for at a German dermatology transplant clinic.

RESULTS

Significantly lower TSB scores were noted in OTR not developing a first keratinocyte cancer compared to OTR developing keratinocyte cancer during their follow-up period ( P  = 0.005). Regression analysis assigned a significantly higher risk for the development of first keratinocyte cancer to OTR with TSB scores >10. In total 70.7% of OTR with a history of ≥1 keratinocyte cancer reported intermittent sunscreen use, while daily sunscreen use was overall associated with female gender (21.3%) and age >30 years (17.6%).

CONCLUSIONS

The risk of OTR for developing keratinocyte cancer is reflected by their UV-exposure patterns, which may be assessed by the TSB-score, a scored risk assessment tool. Complementing clinical data, the TSB score may help clinicians to identify OTR at particularly high risk for keratinocyte cancer and to endorse intensified prevention strategies and dermato-oncologic care.

Curcumin-gold-polyethylene glycol nanoparticles as a nanosensitizer for photothermal and sonodynamic therapies: In vitro and animal model studies

Photothermal and ultrasound therapies are novel non-invasive strategies for tumor treatment which are equipped with a photosensitizer and sonosensitizer subsequent activation by laser irradiation and ultrasound exposure. In this study, curcumin-gold-polyethylene glycol nanoparticles (Cur-Au NPs-PEG) were synthesized, and the dual role in photothermal (PTT) and sonodynamic (SDT) therapies of melanoma cancer was evaluated. The toxicity effect of Cur-Au NPs-PEG against a mouse malignant melanoma cell line C540 (B16/F10) was firstly inspected in vitro. Cur-Au NPs-PEG provided a hyperthermal microenvironment and generated reactive oxygen species upon PTT and STD, respectively, with representing synergism effects. Studies in vivo in a tumor-bearing animal also demonstrate the superiority of PTT and SDT in destroying melanoma tumor.

Skin cancer in organ transplant recipients: dynamics in the incidence and clinical predictors for the first and subsequent post-transplant non-melanoma skin cancer

BACKGROUND

Risk factors for primary non-melanoma skin cancer (NMSC) in organ transplant recipients (OTR) have been well described. Data for subsequent NMSC and dynamics in their occurrence in OTR are limited.

OBJECTIVE

To study long-term risks of primary and subsequent NMSC and associated risk factors in OTR.

METHODS

A retrospective single-centre cohort study analysing medical records from a dermato-oncological specialty clinic.

RESULTS

Of 464 OTR 110 (23.7%) developed at least one, 73 (15.7%) two and 51 (11%) three NMSC during a median follow-up of 9.6 years. Cumulative incidences at 5, 10 and 15 years were 14.7%, 23.5% and 34.5% for the first and 75.8%, 86.5% and 93.3% for the second. Median time-to-diagnosis declined from 22 years (95% CI 19-25) to 2 years (1-3) and about 1 year (0-2) for the first, second and third NMSC. Risk for subsequent NMSC only partially related to risk factors for the primary NMSC. Histologic type of the first NMSC predicted subtype and time-to-diagnosis of the subsequent NMSC.

CONCLUSIONS

A first post-transplant NMSC, particularly a SCC, confers a high risk for subsequent NMSC arising with accelerated dynamics. Risk-adapted dermato-oncologic surveillance is advisable for all OTR.

Interleukin-22 and Cyclosporine in Aggressive Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinomas (SCCs) account for up to 10,000 deaths annually in the United States. Most of the more than 700,000 SCCs diagnosed are cured by excision with clear margins; however, metastasis can occur despite seemingly adequate treatment in some cases. Immune-suppressed organ transplant recipients are 60 to 100 times more likely to develop SCC than immune-competent individuals. Transplant-associated SCCs occur more frequently and behave more aggressively, showing higher risk of recurrence and metastasis. This article identifies a potential role for interleukin-22 in driving SCC proliferation, particularly in solid organ transplant recipients taking cyclosporine.

Cyclosporine A immunosuppression drives catastrophic squamous cell carcinoma through IL-22

Immune-suppressed organ transplant recipients (OTRs) can develop catastrophic squamous cell carcinoma (SCC), characterized by multiple primary tumors, extensive body surface area involvement, or metastases. There are currently no curative systemic therapies available. We previously showed that IL-22 enhances SCC proliferation. Herein, we examined links between cyclosporine (CSA), IL-22, and SCC in patients, cell lines, and mice with UV light-induced SCC. Eighteen of 114 OTRs developed catastrophic SCC, which was strongly associated with CSA treatment. We found that CSA drives T cell polarization toward IL-22-producing T22 cells, and CSA treatment increased IL-22 receptor in SCC cells. SCC tissue from OTRs showed increased expression of IL-22RA1. CSA potentiated rescue by IL-22 of serum-starved SCC cells; treatment of SCC cells with IL-22 and CSA increased both their migratory and invasive capacity. In a UV-induced model of SCC in SKH-1 immunocompetent mice, treatment with anti-IL-22 antibody reduced tumor number and tumor burden. We found that catastrophic SCC in OTRs is associated with CSA use, which may be acting by favoring T22 polarization. Since anti-IL-22 antibody administration decreased tumor number and tumor burden in vivo, blockade of the IL-22 axis may be developed as a viable therapeutic option for catastrophic SCC.

Peritumoral dermis of squamous cell carcinomas in renal transplant recipients contains less CD11c+ myeloid dendritic cells and FoxP3+ T cells compared to immunocompetent controls

BACKGROUND

Renal transplant recipients (RTR) have an increased risk of developing cutaneous squamous cell carcinomas (SCC). These SCC are often more aggressive than SCC in immunocompetent individuals.

OBJECTIVES

In this comparative study, we analysed the cell composition in the tissue immediately surrounding invasive SCC in immunosuppressed RTR and immunocompetent controls in an effort to further elucidate the role of the local immune system.

METHODS

Morphology and quantity of various dendritic cell (DC) subsets, macrophages and FoxP3+ T cells were analysed by immunohistochemical staining.

RESULTS

The number of CD11c+ myeloid DC and FoxP3+ T cells was significantly reduced in RTR, whereas the number of plasmacytoid DC, Langerhans cells and macrophages was similar in RTR and controls.

CONCLUSIONS

A reduction in CD11c+ mDC in peritumoral dermis in RTR might contribute to impaired immunosurveillance thus giving rise to an increased risk to develop aggressive SCC in these patients.

Pharmacologically antagonizing the CXCR4-CXCL12 chemokine pathway with AMD3100 inhibits sunlight-induced skin cancer

One way sunlight causes skin cancer is by suppressing anti-tumor immunity. A major mechanism involves altering mast cell migration via the C-X-C motif chemokine receptor 4-C-X-C motif chemokine ligand 12 (CXCR4-CXCL12) chemokine pathway. We have discovered that pharmacologically blocking this pathway with the CXCR4 antagonist AMD3100 prevents both UV radiation-induced immune suppression and skin cancer. The majority of control mice receiving UV-only developed histopathologically confirmed squamous cell carcinomas. In contrast, skin tumor incidence and burden was significantly lower in AMD3100-treated mice. Perhaps most striking was that AMD3100 completely prevented the outgrowth of latent tumors that occurred once UV irradiation ceased. AMD3100 protection from UV immunosuppression and skin cancer was associated with reduced mast cell infiltration into the skin, draining lymph nodes, and the tumor itself. Thus a major target of CXCR4 antagonism was the mast cell. Our results indicate that interfering with UV-induced CXCL12 by antagonizing CXCR4 significantly inhibits skin tumor development by blocking UV-induced effects on mast cells. Hence, the CXCR4-CXCL12 chemokine pathway is a novel therapeutic target in the prevention of UV-induced skin cancer.

Characterization of monocyte-derived dendritic cells from immunosuppressed renal transplant recipients with and without squamous cell carcinomas

Renal transplant recipients (RTR) have a high risk of tumour development, especially cutaneous squamous cell carcinomas (SCC), due to long-term immunosuppressive therapy. RTR may develop multiple lesions over short time periods, and these are often more aggressive with a higher risk of local recurrence and metastasis resulting in increased morbidity and mortality in these patients. Therefore, we took the first step towards evaluating the possibility of generating a therapeutic vaccine based on monocyte-derived dendritic cells (moDC) for these patients. We analysed the phenotype and cytokine/chemokine profile of moDC from long-term immunosuppressed RTR with and without previous SCC. The number of peripheral blood mononuclear cells (PBMC) isolated per ml blood as well as the efficiency of generating moDC from peripheral blood mononuclear cells (PBMC) was similar in patients and immunocompetent controls. Phenotype and cytokine/chemokine profile of the moDC from immunosuppressed patients were similar to those from immunocompetent controls, making moDC-based immunotherapy a potential future treatment option for RTR with multiple SCC.

Increased Tc22 and Treg/CD8 ratio contribute to aggressive growth of transplant associated squamous cell carcinoma

Immune suppressed organ transplant recipients suffer increased morbidity and mortality from primary cutaneous SCC. We studied tumor microenvironment in transplant-associated SCC (TSCC), immune-competent SCC and normal skin by IHC, IF and RT-PCR on surgical discard. We determined T cell polarization in TSCC and SCC by intracellular cytokine staining of T cell crawl outs from human skin explants. We studied the effects of IL-22, an inducer of keratinocyte proliferation, on SCC proliferation in vitro. SCC and TSCC are both associated with significantly higher numbers of CD3(+) and CD8(+) T cells compared to normal skin. TSCC showed a higher proportion of Foxp3(+) T regs to CD8(+) T cells compared to SCC and a lower percentage of IFN-γ producing CD4(+) T cells. TSCC, however, had a higher percentage of IL-22 producing CD8(+) T cells compared to SCC. TSCC showed more diffuse Ki67 and IL-22 receptor (IL-22R) expression by IHC. IL-22 induced SCC proliferation in vitro despite serum starvation. Diminished cytotoxic T cell function in TSCC due to decreased CD8/T-reg ratio may permit tumor progression. Increased IL-22 and IL-22R expression could accelerate tumor growth in transplant patients. IL-22 may be an attractive candidate for targeted therapy of SCC without endangering allograft survival.

Increased incidence and mortality associated with skin cancers after cardiac transplant

Skin cancer incidence has been shown to be increased in the context of transplant-associated immunosuppression. There is, however, limited information specifically about the incidence of skin cancer after cardiac transplantation in the United States. A 10-year retrospective cohort study of 6271 heart transplants at 32 US transplant centers revealed increased postprocedure incidence of nonmelanoma and melanoma skin cancers, especially cutaneous squamous cell carcinoma, for which the incidence increased from 4- to 30-fold compared to the age and gender equivalent general population. Incidence of skin cancer in this study was consistent with prior single-center data regarding cardiac transplant patients. Comparison of all-cause mortality statistics for patients with basal cell carcinoma, squamous cell carcinoma and melanoma, respectively, demonstrated increased mortality associated with melanoma. Skin cancer screening and prophylaxis may be of some utility in reducing morbidity and mortality in cardiac transplant patients.

Tumor-associated macrophages in the cutaneous SCC microenvironment are heterogeneously activated

Tumor-associated macrophages (TAMs) may have an important role in tumor immunity. We studied the activation state of TAMs in cutaneous SCC, the second most common human cancer. CD163 was identified as a more abundant, sensitive, and accurate marker of TAMs when compared with CD68. CD163(+) TAMs produced protumoral factors, matrix metalloproteinases 9 and 11 (MMP9 and MMP11), at the gene and protein levels. Gene set enrichment analysis (GSEA) was used to evaluate M1 and M2 macrophage gene sets in the SCC genes and to identify candidate genes in order to phenotypically characterize TAMs. There was coexpression of CD163 and alternatively activated "M2" markers, CD209 and CCL18 (chemokine (C-C motif) ligand 18). There was enrichment for classically activated "M1" genes in SCC, which was confirmed in situ by colocalization of CD163 and phosphorylated STAT1 (signal transducer and activator of transcription 1), IL-23p19, IL-12/IL-23p40, and CD127. Also, a subset of TAMs in SCC was bi-activated as CD163(+) cells expressed markers for both M1 and M2, shown by triple-label immunofluorescence. These data support heterogeneous activation states of TAMs in SCC, and suggest that a dynamic model of macrophage activation would be more useful to characterize TAMs.

Immunosuppression and squamous cell carcinoma: a focus on solid organ transplant recipients

As transplant medicine advances, new immunosuppressive regimens are increasing the long-term survival of solid organ transplant recipients (SOTRs). This growing population is at significantly increased risk for developing cutaneous malignancies, particularly squamous cell carcinoma (SCC), as a result of chronic immunosuppression. Conventional risk factors for the development of skin cancer, including fair skin type, advanced age, sun exposure, and genetic predisposition, also play a crucial role in the initiation and progression of SCC in SOTRs. Immunosuppressed patients develop more aggressive and more numerous SCCs than immunocompetent individuals, however. It is important to understand the mechanisms underlying immunosuppression-mediated SCC development to identify prognostic markers and to develop effective prevention and treatment strategies. This article addresses the fundamental differences between SCC in SOTRs and those in the general population, focusing on the role that immunosuppression plays in the pathogenesis of this malignancy.

Skin Cancer After Transplantation: A Guide for the General Surgeon

The success of organ transplantation has been accompanied by serious concerns regarding the incidence and management of potentially catastrophic cutaneous carcinogenesis in transplant recipients. Delivery of the highest quality of care requires a concerted effort toward collaboration between multiple surgical and medical specialties. The purpose of this review is to provide the general surgeon with a practical, user-friendly guide to the important components of comprehensive dermatologic care for organ transplant recipients (OTRs) with references to more detailed sources of information.