Switching from tacrolimus to sirolimus halts the appearance of new sebaceous neoplasms in Muir-Torre syndrome

Is HLA type a possible cancer risk modifier in Lynch syndrome?

Lynch syndrome (LS) is the most common inherited cancer syndrome. It is inherited via a monoallelic germline variant in one of the DNA mismatch repair (MMR) genes. LS carriers have a broad 30% to 80% risk of developing various malignancies, and more precise, individual risk estimations would be of high clinical value, allowing tailored cancer prevention and surveillance. Due to MMR deficiency, LS cancers are characterized by the accumulation of frameshift mutations leading to highly immunogenic frameshift peptides (FSPs). Thus, immune surveillance is proposed to inhibit the outgrowth of MMR-deficient cell clones. Recent studies have shown that immunoediting during the evolution of MMR-deficient cancers leads to a counter-selection of highly immunogenic antigens. The immunogenicity of FSPs is dependent on the antigen presentation. One crucial factor determining antigen presentation is the HLA genotype. Hence, a LS carrier's HLA genotype plays an important role in the presentation of FSP antigens to the immune system, and may influence the likelihood of progression from precancerous lesions to cancer. To address the challenge of clarifying this possibility including diverse populations with different HLA types, we have established the INDICATE initiative (Individual cancer risk by HLA type, http://indicate-lynch.org/), an international network aiming at a systematic evaluation of the HLA genotype as a possible cancer risk modifier in LS. Here we summarize the current knowledge on the role of HLA type in cancer risk and outline future research directions to delineate possible association in the scenario of LS with genetically defined risk population and highly immunogenic tumors.

Vaccines for immunoprevention of DNA mismatch repair deficient cancers

The development of cancer vaccines to induce tumor-antigen specific immune responses was sparked by the identification of antigens specific to or overexpressed in cancer cells. However, weak immunogenicity and the mutational heterogeneity in many cancers have dampened cancer vaccine successes. With increasing information about mutational landscapes of cancers, mutational neoantigens can be predicted computationally to elicit strong immune responses by CD8 +cytotoxic T cells as major mediators of anticancer immune response. Neoantigens are potentially more robust immunogens and have revived interest in cancer vaccines. Cancers with deficiency in DNA mismatch repair have an exceptionally high mutational burden, including predictable neoantigens. Lynch syndrome is the most common inherited cancer syndrome and is caused by DNA mismatch repair gene mutations. Insertion and deletion mutations in coding microsatellites that occur during DNA replication include tumorigenesis drivers. The induced shift of protein reading frame generates neoantigens that are foreign to the immune system. Mismatch repair-deficient cancers and Lynch syndrome represent a paradigm population for the development of a preventive cancer vaccine, as the mutations induced by mismatch repair deficiency are predictable, resulting in a defined set of frameshift peptide neoantigens. Furthermore, Lynch syndrome mutation carriers constitute an identifiable high-risk population. We discuss the pathogenesis of DNA mismatch repair deficient cancers, in both Lynch syndrome and sporadic microsatellite-unstable cancers. We review evidence for pre-existing immune surveillance, the three mechanisms of immune evasion that occur in cancers and assess the implications of a preventive frameshift peptide neoantigen-based vaccine. We consider both preclinical and clinical experience to date. We discuss the feasibility of a cancer preventive vaccine for Lynch syndrome carriers and review current antigen selection and delivery strategies. Finally, we propose RNA vaccines as having robust potential for immunoprevention of Lynch syndrome cancers.

Kidney Transplant Recipient With Multiple Contemporaneous Malignancies Secondary to Muir-Torre Syndrome

Muir-Torre Syndrome (MTS) is a rare autosomal-dominant genetic condition linked to germline mutations in DNA mismatch repair (MMR) genes, resulting in microsatellite instability. It is considered a variant of Lynch syndrome characterized by the association of at least one sebaceous skin tumor and at least one internal malignancy. In addition, it has been shown that a latent phenotype of MTS might be unmasked in transplant organ recipients and immunosuppressed patients. The diagnosis and treatment of such cases require a multidisciplinary approach. Here, we present a case of a kidney transplant recipient who developed multiple sebaceous carcinomas 16 years after kidney transplantation and daily immunosuppressive medication. The patient then developed multiple contemporaneous internal malignancies in the esophagus and colon with metastases to the lung, thyroid, and lymph nodes, all of which were eventually linked to MTS. To our knowledge, this is the first reported case of MTS in the Arab world and the first reported case of esophageal cancer in relation to MTS in a transplant recipient. Because patients with MTS have a high tendency of developing malignancies, patients with a strong family history of malignancies, any known mutations, or an immunocompromised status should be included in an extensive screening program.

Systematic review of sirolimus in dermatological conditions

Sirolimus is a mammalian target of rapamycin inhibitor (mTORI) with anti-proliferative, antiangiogenic and immunosuppressive properties. While approved in Australia as an anti-rejection medication for renal transplant patients, there is mounting evidence regarding the utility of oral and topical sirolimus in treating a plethora of dermatological conditions or conditions with cutaneous manifestations. Our aim was to present an overview of the evidence for current usage and breadth of the application of sirolimus in dermatology. We carried out a systematic review of all the literature published up to 31 August 2019 on oral and topical sirolimus with respect to dermatological conditions or conditions otherwise relevant to dermatology. While 3368 papers were initially produced in our search, 238 papers met our inclusion criteria and were examined in our review. The conditions examined were categorised into genodermatoses (9 conditions), infection (1 condition), inflammatory/autoimmune (10 conditions), neoplasm (3 conditions) and vascular (17 conditions). We extracted data on first author, publication year, journal, characteristics of the study and study patients, condition, drug modalities, drug efficacy, side effects, blood level of mTORI, co-interventions and follow-up. While there is level 1 evidence for the efficacy of sirolimus in conditions such as tuberous sclerosis complex (TSC) and GVHD prophylaxis, for many other conditions, the evidence is limited to level 4 evidence. Regarding oral systemic therapy, dosing regimens varied with the most common for children 0.8mg/m² twice daily and for adults 1 mg twice daily. Doses were often adjusted to reach a typical trough level of between 5 and 15 ng/mL, though targets often varied. In the overall majority of cases, side effects were minimal or tolerable, including mucositis, cytopenias, lipid abnormalities and nausea/vomiting, and only a few cases had to stop due to adverse effects. Regarding topical therapy, concentration of formulations varied from 0.1% to 1% and were compounded into creams, ointments or gels and administered typically once or twice per day. The most common side effect was skin irritation. There were a number of limitations to our study. In particular, many of the published studies were case reports or case series with no comparator arm, leading to susceptibility of bias in conclusions drawn, in particular a high likelihood of publication bias. Given the heterogeneity amongst studies, comparisons or aggregation of results was difficult. There continues to be growing use of oral and topical sirolimus in dermatological conditions. It provides new therapeutic options to patients where previous therapies have either failed or are limited due to toxicity. However, further studies are warranted.

Case Report: A Frameshift Mutation in MSH2 Exon 2 in a Kidney Recipient With Muir-Torre Syndrome

Muir-Torre syndrome (MTS), a rare subtype of Lynch syndrome, is mostly autosomal dominant, which is caused by germline mutations in DNA mismatch repair (MMR) genes, the resulting microsatellite instability (MSI) of which increases the risk of developing sebaceous and other visceral tumors. Several reports have showed an association between immunosuppressive agents and the progression of latent MTS. In this report, we described a 41-year-old man with a history of kidney transplantation, having a rapid growth of the nodule on the anterior chest under immunosuppressive therapy, which was histologically proved to be sebaceous carcinoma. Systemic evaluation for visceral malignancies revealed sigmoid adenocarcinoma. These findings were consistent with the clinical diagnosis of MTS. Histological findings showed an absence of MMR proteins, including MSH2 and MSH6 both in the sebaceous carcinoma and sigmoid adenocarcinoma on immunohistochemical (IHC) analysis. A frame-shift mutation of c.229_230delAG (p. Ser77fs) in the MSH2 exon 2 in the lesion was detected by next-generation sequencing (NGS) analysis. This case report not only reveals a new site of MSH2 mutation in this family of East Asian descent but also highlights the importance of adequate diagnosis for Muir-Torre syndrome, as well as further prevention of the development of latent visceral tumors in kidney transplant recipients.

Muir-Torre Syndrome With a Frame-shift Mutation in the MSH2 Gene: A Rare Case Report and Literature Review

Muir-Torre syndrome is a rare subtype of Lynch syndrome characterized by coincidence of skin neoplasm and visceral malignancies. Here, we report a case of this rare disease, whose diagnosis of the syndrome was first suspected by the pathologist. This was a 60-yr-old woman who presented with an axillary skin nodule, which was diagnosed as basal cell carcinoma. Further inquiry revealed that she was hospitalized for evaluation of a recurrent vaginal stump endometrial carcinoma. Histologic workup and immunohistochemistry for mismatch repair proteins of both the skin and vaginal tumor suggested the possibility of Muir-Torre syndrome. NexGen sequencing identified a frame-shift mutation in the MSH2 gene. The patient was found to have a metachronous colorectal carcinoma, uterine endometrial carcinoma, and skin cancer from 1998 to 2016. Five family members had also suffered from colorectal cancer or glioma. This case report illustrates the importance of the multidisciplinary care approach, mismatch repair protein and gene testing, and detailed medical history taking into consideration the diagnosis of Muir-Torre syndrome.

Epidermoid cysts in kidney transplant patients receiving tacrolimus

We present a series of three kidney transplant patients developing epidermoid cysts after receiving oral tacrolimus for long-term prevention of rejection of the allograft. Cyclosporin A has been known to show this cutaneous adverse drug reaction, but this is the first series of patients with epidermoid cysts following tacrolimus to the best of our knowledge.

Muir-Torre syndrome: sebaceous carcinoma concurrent with colon cancer in a kidney transplant recipient; a case report

BACKGROUND

Sebaceous carcinoma is a rare but progressive malignant skin cancer, and the incidence is approximately five times higher in post-transplant patients than in people who have not received kidney transplants. Sebaceous carcinoma is sometimes found concurrently with visceral cancers and a genetic abnormality, Muir-Torre syndrome. We report the case of a female kidney transplant recipient with sebaceous carcinoma concurrent with colon cancer 10 years after transplantation.

CASE PRESENTATION

A 43-year-old woman was admitted due to a rapidly progressive tumor on her head. Histologically, the tumor was diagnosed as sebaceous carcinoma. We diagnosed her with Muir-Torre syndrome based on the following evidence: 1) high prevalence of microsatellite instability in gene locus assay, 2) absence of mismatch repair proteins in the sebaceous carcinoma on immunohistochemical analysis, and 3) a genetic mutation of 1226_1227delAG in the MSH2 exon 7 in the lesion detected by DNA sequencing analysis. Several reports have shown an association between immunosuppressive agents and latent Muir-Torre syndrome progression. Therefore, the progression of colon cancer in this case originated from her genetic mutation for Muir-Torre syndrome and long-term use of immunosuppressive agents.

CONCLUSION

This case report not only highlights the importance of adequate diagnosis and therapy for Muir-Torre syndrome, but also suggests the further prevention of the development of malignant tumors in kidney transplant recipients. Physicians should be mindful that sebaceous carcinoma in kidney transplant recipients is highly concurrent with Muir-Torre syndrome.

Role of microsatellite instability, immunohistochemistry and mismatch repair germline aberrations in immunosuppressed transplant patients: a phenocopy dilemma in Muir-Torre syndrome

Sebaceous tumours and keratoacanthomas are uncommon neoplasms that constitute important clinical criteria for Muir-Torre syndrome (MTS) diagnosis. In MTS patients, the increased risk of developing synchronous or metachronous visceral malignancies is characterised by autosomal dominant inheritance. However, there are further conditions, other than MTS, that increase the risk of sebaceous neoplasms, e.g. iatrogenic immunosuppression. In this latter scenario, the sebaceous tumours can present microsatellite instability (MSI) and loss of mismatch repair (MMR) proteins, characteristic of hereditary syndromes, even in the absence of MMR germline mutations. In this article, we examine transplant probands in which the immunosuppressive therapies unmask the MTS cutaneous phenotypes, showing MSI and loss of MMR protein expression, as demonstrated by immunohistochemistry (IHC). Furthermore, MMR genes sequencing analysis identified the presence of germline mutations in MTS-suspected individuals, in the absence of a visceral MTS phenotype. It is well known that immunosuppression plays a central role in the development of sebaceous tumours in both MTS and in non-syndromic settings. Sebaceous skin tumours' MSI status and IHC profiles can be influenced by epigenetic or iatrogenic factors; however, they constitute valuable tools and a cost-effective approach to screen individuals who otherways should undergo MMR genes direct sequencing in the context of immunosuppression. In this complex setting, the choice of the immunosuppressive drug becomes a critical decision for the management of both MTS and sporadic transplant patients, which may benefit from the administration of immunosuppressive drugs, resulting in a low impact on skin cancerogenesis.

[Muir-Torre syndrome associated with Waldenstrom's macroglobulinemia]

BACKGROUND

Muir-Torre syndrome (MTS), a cutaneous variant of Lynch syndrome, consists of hereditary predisposition to cutaneous tumours and gastrointestinal and gynaecological neoplasms, with autosomal dominant transmission. It is associated with mutations in genes coding for proteins in the DNA mismatch repair system.

PATIENTS AND METHODS

Herein, we report a case of a male patient presenting Waldenstrom's macroglobulinemia since the age of 50 and which, after the age of 65 years, developed into sebaceous tumours (5 sebaceous adenomas, 1 sebaceoma, 1 sebaceous carcinoma) and colonic lesions (4 adenomas). The clinical phenotype was consistent with MTS. Somatic analysis carried out on one sebaceous tumour showed instability of the microsatellites with loss of expression of MSH2 and MSH6 although constitutional genetic analysis showed no germline mutations known to be harmful.

DISCUSSION

This noteworthy case raises a number of questions, including the possibility of association between STM and Waldenstrom's macroglobulinemia, which is discussed herein.

Muir-Torre syndrome (MTS): An update and approach to diagnosis and management

Muir-Torre syndrome (MTS) is a rare genetic condition that predisposes individuals to skin tumors and visceral malignancies. Because of the potentially aggressive nature of internal malignancies and sebaceous carcinoma, and the tendency to have multiple low-grade visceral cancers, close cancer surveillance is required in individuals and their families with this usually autosomal dominant disorder. Although the majority of MTS is caused by mutations in DNA mismatch repair genes resulting in microsatellite instability, a newly described subtype of MTS does not demonstrate microsatellite instability and may be inherited in an autosomal recessive pattern. In addition, MTS may be unmasked in transplant recipients taking specific immunosuppressant drugs or other immunosuppressed patients. Neoplasms may be subject to immunohistochemistry or both immunohistochemistry and genetic testing to confirm the diagnosis of MTS. Here, we offer an update and an approach to the diagnosis and management of MTS with a particular emphasis on the role of immunohistochemistry and genetic testing.

Defective DNA mismatch repair activity is common in sebaceous neoplasms, and may be an ineffective approach to screen for Lynch syndrome

A subset of individuals with Lynch syndrome (LS) has a variant called Muir-Torre syndrome (MTS) where patients develop multiple sebaceous neoplasms. Absence of gene expression and microsatellite instability (MSI) have been welldocumented in LS neoplasms. It is unclear whether the presence of these abnormalities in isolated sebaceous neoplasms would indicate the likely presence of otherwise unsuspected LS or MTS. 164 specimens of sporadic cutaneous sebaceous neoplasms were obtained. IHC was performed for expression of the DNA mismatch repair (MMR) genes MSH2 and MLH1. A 5-marker mononucleotide repeat microsatellite panel was analyzed to detect MSI, and two or more mutated markers were required for MSI. 164 sebaceous neoplasms were obtained from 162 patients. IHC data was successfully obtained from 162 samples and MSI data was obtained from 138 samples. 50/162 (31%) had abnormal IHC with loss of staining for either MSH2 (37/162, 23%), MLH1 (9/162, 5%) or both (4/162, 2%). 37% (52/138) of the tumors had MSI. 82% (111/136) of those with both IHC and MSI results correlated as expected. 18% (25/136) showed discordance between IHC and MSI. 69/163 (42%) had either abnormal IHC or MSI, indicating deficient DNA MMR activity. Given the substantial proportion of DNA MMR deficiency in these sebaceous neoplasms, screening for DNA MMR defects in sebaceous neoplasms would not appear to be an effective way to distinguish patients with LS or MTS from those with sporadic skin lesions and an ordinary risk of cancer.

Muir-Torre syndrome in a haemodialysis patient

Muir–Torre syndrome (MTS) is a rare inherited cancer syndrome with variable penetrance. MTS follows an autosomal-dominant pattern of inheritance, and is a subtype of Lynch syndrome [formally known as hereditary non-polyposis colorectal cancer (HNPCC)]. MTS is caused by mutations in one of several mismatch repair genes. Patients typically present with sebaceous neoplasms (sebaceous adenoma, sebaceous epithelioma, or sebaceous carcinoma) or with multiple keratoacanthomas. These patients also have an increased lifetime risk of visceral malignancies, typically affecting the colon, ovary, endometrium, genitourinary tract and small bowel. We describe a case of MTS in a haemodialysis patient and implications for transplant listing.

Immunosuppression and sebaceous tumors: a confirmed diagnosis of Muir-Torre syndrome unmasked by immunosuppressive therapy

Muir-Torre syndrome (MTS) is an autosomal dominant genodermatosis caused by mutations in the DNA mismatch repair genes MLH1 and MSH2. This case describes a patient with an extensive family history of colon cancer who experienced the onset of multiple sebaceous adenomas and carcinomas after undergoing kidney transplantation and receiving immunosuppressive therapy. The finding of deficient MSH2 expression in the immunohistochemical analysis of a sebaceous carcinoma prompted genetic testing for a systemic mutation in the mismatch repair gene. A systemic mutation of the MSH2 gene was detected and, despite the absence of a visceral malignancy, the diagnosis of MTS was made. Immunosuppression has previously been thought to play a possible role in unmasking a latent MTS phenotype in transplant recipients, but systemic mutations have not previously been analyzed. The relationship between immunosuppression and sebaceous tumors with the possibility of unmasking a MTS phenotype in transplant recipients is discussed.

[Immunosuppressive therapy after transplantation. Dermatologic relevance and pathomechanisms]

Immunosuppressive therapy keeps rejection in check following solid organ transplantation. Drug reactions, inflammatory and infectious skin conditions frequently follow. Specific side effects can be avoided by switching individual agents. In addition to UV light, immunosuppressants are the most important driver for squamous cell carcinoma of the skin (SCC). Beyond immunosuppression, cyclosporine A promotes carcinogenesis by TGF beta and VEGF, while mTOR inhibitors are antiproliferative. Azathioprine photosensitizes to UVA and enables UVA to damage DNA directly. To fight skin cancer, global reduction of immunosuppression is the most effective measure. Switching calcineurin inhibitors to mTOR inhibitors is probably to be recommended, while omitting azathioprine may potentially be advisable in recurrent SCC.

Skin cancers associated with HIV infection and solid-organ transplantation among elderly adults

Immunosuppression may be etiologic for some skin cancers. We investigated the impact of human immunodeficiency virus (HIV) infection and solid-organ transplantation on skin cancer risk. We conducted a population-based case-control study among elderly U.S. adults (non-Hispanic whites, age 67 years or older), using Surveillance, Epidemiology and End Results Medicare linked data. The study comprised 29,926 skin cancer cases (excluding basal cell and squamous cell carcinomas) and 119,704 controls, frequency-matched by gender, age and calendar year (1987-2002). Medicare claims identified solid-organ transplantation or HIV infection before cancer diagnosis/control selection. As negative controls, we evaluated other medical conditions (e.g., hypertension and depression) and cancers (breast, colon and prostate) not linked to immunosuppression. Odds ratios (ORs) compared prevalence in cases and controls, adjusted for matching factors and number of prior physician claims. Risks of Kaposi sarcoma (N = 602) and cutaneous non-Hodgkin lymphoma (N = 1,836) were increased with solid-organ transplantation (OR [95%CI]: 11.06 [5.27-23.23] and 2.27 [1.00-5.15], respectively) and HIV infection (21.58 [11.94-38.99] and 2.41 [1.05-5.52], respectively). Solid-organ transplantation was also associated with increased risks of Merkel cell carcinoma (N = 1,286; OR [95%CI] 4.95 [2.62-9.34]) and other cutaneous sarcomas (N = 972; 4.19 [1.83-9.56]). Solid-organ transplantation was nonsignificantly associated with melanoma (N = 23,974; (OR 1.36 [95%CI 0.98-1.88]). Null or weak associations were observed for negative control medical conditions and cancers. Solid-organ transplantation and HIV infection were followed by increased risk for some skin cancer subtypes among elderly adults. These results highlight the potential role of immunity in development of skin cancers.

Gene expression patterns in mismatch repair-deficient colorectal cancers highlight the potential therapeutic role of inhibitors of the phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin pathway

PURPOSE

High-frequency microsatellite-instable (MSI-H) tumors account for approximately 15% of colorectal cancers. Therapeutic decisions for colorectal cancer are empirically based and currently do not emphasize molecular subclassification despite an increasing collection of gene expression information. Our objective was to identify low molecular weight compounds with preferential activity against MSI colorectal cancers using combined gene expression data sets.

EXPERIMENTAL DESIGN

Three expression/query signatures (discovery data set) characterizing MSI-H colorectal cancer were matched with information derived from changes induced in cell lines by 164 compounds using the systems biology tool "Connectivity Map." A series of sequential filtering and ranking algorithms were used to select the candidate compounds. Compounds were validated using two additional expression/query signatures (validation data set). Cytotoxic, cell cycle, and apoptosis effects of validated compounds were evaluated in a panel of cell lines.

RESULTS

Fourteen of the 164 compounds were validated as targeting MSI-H cell lines using the bioinformatics approach; rapamycin, LY-294002, 17-(allylamino)-17-demethoxygeldanamycin, and trichostatin A were the most robust candidate compounds. In vitro results showed that MSI-H cell lines due to hypermethylation of MLH1 are preferentially targeted by rapamycin (18.3 versus 4.4 mumol/L; P = 0.0824) and LY-294002 (15.02 versus 10.37 mumol/L; P = 0.0385) when compared with microsatellite-stable cells. Preferential activity was also observed in MSH2 and MSH6 mutant cells.

CONCLUSION

Our study shows that the phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin pathway is of special relevance in mismatch repair-deficient colorectal cancer. In addition, we show that amalgamation of gene expression information across studies provides a robust approach for selection of potential therapies corresponding to specific groups of patients.

The role of mTOR inhibitors in the management of posttransplant malignancy

Organ transplant recipients given mammalian target of rapamycin inhibitor (mTORi) have reduced incidence of de novo posttransplant malignancies (dNPTMs). Posttransplant Kaposi's sarcoma and nonmelanotic skin malignancies (NMSC) frequently undergo remission/regression after conversion to mTORi immunosuppression (IS), especially early, small, and low-grade lesions, whereas larger, aggressive, and metastatic skin tumors are less likely to respond. mTORi-based IS is effective and well tolerated in orthotopic liver transplant patients with hepatocellular carcinoma (HCC) achieving excellent survival and disease-free intervals, particularly with extended criteria tumors, although the evidence that mTORi prevents HCC recurrence after orthotopic liver transplantation is only suggestive. Regression of metastatic HCC and other tumors and various forms of posttransplant lymphoproliferative disease have occurred after mTOR conversion. Documentation of regression/remission of other solid-organ dNPTM (colon, stomach, breast, etc.) after mTORi conversion is essentially absent with only anecdotal reports lacking follow-up data. Unfortunately, there is not a single reported prospective clinical trial powered for looking at the effect of mTORi IS in transplant recipients. Nevertheless, reduced incidence of all of dNPTMs and remission/regression of the commonest posttransplant tumors with mTOR therapy are strong reasons to expand the use of mTORi.

Epidemiology of nonkeratinocytic skin cancers among persons with AIDS in the United States

OBJECTIVE

Immunosuppression may increase risk for some skin cancers. We evaluated skin cancer epidemiology among persons with AIDS.

DESIGN

We linked data from population-based US AIDS and cancer registries to evaluate risk of nonkeratinocytic skin cancers (melanoma, Merkel cell carcinoma, and appendageal carcinomas, including sebaceous carcinoma) in 497 142 persons with AIDS.

METHODS

Standardized incidence ratios (SIRs) were calculated to relate skin cancer risk to that in the general population. We used logistic regression to compare risk according to demographic factors, CD4 cell count, and a geographic index of ultraviolet radiation exposure.

RESULTS

From 60 months before to 60 months after AIDS onset, persons with AIDS had elevated risks of melanoma (SIR = 1.3, 95% confidence interval 1.1-1.4, n = 292 cases) and, more strongly, of Merkel cell carcinoma (SIR = 11, 95% confidence interval 6.3-17, n = 17) and sebaceous carcinoma (SIR = 8.1, 95% confidence interval 3.2-17, n = 7). Risk for appendageal carcinomas increased with progressive time relative to AIDS onset (P trend = 0.03). Risk of these skin cancers was higher in non-Hispanic whites than other racial/ethnic groups, and melanoma risk was highest among men who have sex with men. Melanoma risk was unrelated to CD4 cell count at AIDS onset (P = 0.32). Risks for melanoma and appendageal carcinomas rose with increasing ultraviolet radiation exposure (P trend <10 and P trend = 10, respectively).

CONCLUSION

Among persons with AIDS, there is a modest excess risk of melanoma, which is not strongly related to immunosuppression and may relate to ultraviolet radiation exposure. In contrast, the greatly increased risks for Merkel cell and sebaceous carcinoma suggest an etiologic role for immunosuppression.

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.

Skin cancer in organ transplant recipients--where do we stand today?

Skin cancers are the most frequent malignancies in organ transplant recipients (OTR), with 95% being nonmelanoma skin cancers (NMSC), especially squamous (SCC) and basal cell carcinomas. Most OTR with a first SCC subsequently develop multiple NMSC within 5 years, highlighting the concept of 'field cancerization', and are also at high risk for noncutaneous cancers. In order to reduce the tumor burden in these patients, their management requires an interdisciplinary approach including revision of immunosuppression, new dermatological treatments and adequate education about photoprotection in specialized dermatology clinics for OTR. Whereas surgery remains the gold-standard therapy for NMSC, noninvasive methods have shown promising results to treat superficial keratoses and subclinical lesions on large body areas. Although the threshold of skin cancer necessitating revision of immunosuppression is debated, this measure should be envisaged at the occurrence of the first SCC, or in case of multiple non-SCC NMSC. While the role of immunosuppressants in the occurrence of NMSC is widely recognized, the best immunosuppressive strategies remain to be defined. Presently, randomized prospective studies assess the burden of new skin tumors, as well as graft and patient survival, in patients with one or several NMSC after the introduction of mTOR (mammalian target of rapamycin) inhibitors.

Tuberous sclerosis complex: advances in diagnosis, genetics, and management

Tuberous sclerosis complex (TSC) is an autosomal dominant multisystem neurocutaneous syndrome characterized by the development of multiple hamartomas distributed throughout the body, skin, brain, heart, kidneys, liver, and lungs. Two-thirds of patients represent sporadic mutations. The classic triad is seizures, mental retardation, and cutaneous angiofibromas. However, the full triad occurs in only 29% of patients; 6% of them lack all three of them. Two tumor suppressor genes responsible for TSC have been identified: TSC1 gene on chromosome 9 and TSC2 on chromosome 16. This article highlights the most recent significant advances in the diagnosis and genetics of TSC, along with a discussion on the limitations and the usefulness of the revised 1998 clinical criteria for the tuberous sclerosis complex. The "ash leaf" macule often comes in other shapes, such as round; most are polygonal, usually 0.5 cm to 2.0 cm in diameter, resembling a thumbprint. Since the death of its describer, Thomas Fitzpatrick, we call each a "Fitzpatrick patch." Special attention is paid in this work to TSC treatment options, including therapeutic trials with rapamycin, also known as sirolimus.

LEARNING OBJECTIVE

After completing this learning activity, participants should familiar with tuberous sclerosis complex, its cutaneous signs and systemic findings stratified by patient age, its genetics, and the potential for meaningful therapeutic intervention.

Sirolimus (rapamycin): from the soil of Easter Island to a bright future

Discovered in fungi in the remote Easter Island, sirolimus (rapamycin) shows potential beyond its obvious antiproliferative and immunosuppressant activity. Studies have demonstrated that sirolimus acts as a vascular endothelial growth factor inhibitor, providing prospective therapeutic benefits and possible prevention of tuberous sclerosis and Kaposi's sarcoma. Its ability to decrease keratinocyte proliferation may help patients with psoriasis. In those with tuberous sclerosis complex, it may prevent the development of hamartomas and reduce or eliminate them once grown by blocking the mammalian target of rapamycin, a critical regulatory kinase. A great advantage for this drug is in the decreased risk of malignancies, including Kaposi's sarcoma, associated with its use compared with other immunosuppressants, namely calcineurin inhibitors. This review will focus on the pharmacology and potential uses of sirolimus.