Sirolimus and secondary skin-cancer prevention in kidney transplantation

Solid tumors following kidney transplantation in children

Kidney transplant recipients have an increased risk of cancer. Data on non-LPD malignancies (solid tumors) in pediatric renal transplant recipients are limited. We performed a cohort study using the NAPRTCS transplant registry to describe the incidence of non-LPD malignancy compared with the general pediatric population. The observed incidence rate of non-LPD malignancy in the NAPRTCS transplant registry was 72.1 per 100,000 person-years (SIR 6.7; 95% CI, 5.3, 8.5); a 6.7-fold increased risk compared with the general pediatric population (10.7 cases per 100,000 person-years). Non-LPD malignancy was diagnosed in 35 subjects at a median of 726 days post-transplant. The most common type of malignancy was renal cell carcinoma. The increased risk of non-LPD malignancy was seen in all patients regardless of age, gender, race, etiology of end-stage kidney disease, and transplant era. The specific type of immunosuppression was not identified as a risk factor. In this first large-scale study of North American pediatric renal transplant recipients, we observed a 6.7-fold increased risk of non-LPD malignancy compared with the general pediatric population. Further examination of this unique patient population may provide greater insight into the impact of transplant and immunosuppression on malignancy risk.

HPV-related cancers after solid organ transplantation in the United States

Transplant recipients have elevated cancer risk including risk of human papillomavirus (HPV)-associated cancers of the cervix, anus, penis, vagina, vulva and oropharynx. We examined the incidence of HPV-related cancers in 187 649 US recipients in the Transplant Cancer Match Study. Standardized incidence ratios (SIRs) compared incidence rates to the general population, and incidence rate ratios (IRRs) compared rates across transplant subgroups. We observed elevated incidence of HPV-related cancers (SIRs: in situ 3.3-20.3, invasive 2.2-7.3), except for invasive cervical cancer (SIR 1.0). Incidence increased with time since transplant for vulvar, anal and penile cancers (IRRs 2.1-4.6 for 5+ vs. <2 years). Immunophenotype, characterized by decreased incidence with HLA DRB1:13 and increased incidence with B:44, contributed to susceptibility at several sites. Use of specific immunosuppressive medications was variably associated with incidence; for example, tacrolimus, was associated with reduced incidence for some anogenital cancers (IRRs 0.4-0.7) but increased incidence of oropharyngeal cancer (IRR 2.1). Thus, specific features associated with recipient characteristics, transplanted organs and medications are associated with incidence of HPV-related cancers after transplant. The absence of increased incidence of invasive cervical cancer highlights the success of cervical screening in this population and suggests a need for screening for other HPV-related cancers.

Selective anti-cancer agents as anti-aging drugs

Recent groundbreaking discoveries have revealed that IGF-1, Ras, MEK, AMPK, TSC1/2, FOXO, PI3K, mTOR, S6K, and NFκB are involved in the aging process. This is remarkable because the same signaling molecules, oncoproteins and tumor suppressors, are well-known targets for cancer therapy. Furthermore, anti-cancer drugs aimed at some of these targets have been already developed. This arsenal could be potentially employed for anti-aging interventions (given that similar signaling molecules are involved in both cancer and aging). In cancer, intrinsic and acquired resistance, tumor heterogeneity, adaptation, and genetic instability of cancer cells all hinder cancer-directed therapy. But for anti-aging applications, these hurdles are irrelevant. For example, since anti-aging interventions should be aimed at normal postmitotic cells, no selection for resistance is expected. At low doses, certain agents may decelerate aging and age-related diseases. Importantly, deceleration of aging can in turn postpone cancer, which is an age-related disease.

Conversion to mTOR-inhibitor-based immunosuppression: which patients and when?

Mammalian target of rapamycin (mTOR) inhibitors are currently considered an alternative immunosuppressive treatment that can prevent the nephrotoxicity, viral infections and malignancies that are associated with calcineurin inhibitor-based immunosuppressive regimens. However, the side effects of mTOR-inhibitor-based regimens lead to frequent treatment discontinuations, and not all patients seem to have the same benefits from conversion to mTOR inhibitors. This review focuses on long-term results of trials that have assessed early and late conversion to sirolimus or everolimus. The renal benefit of late conversion (≥1 year post transplantation) is limited, except in patients with good renal function and without proteinuria. Early conversion to mTOR inhibitors in the first 6 months, in combination with mycophenolate mofetil, could be an appropriate strategy for maintenance therapy in renal transplant recipients with a low immunological risk after careful screening at the time of conversion. Good renal function (glomerular filtration rate >40 ml/ minute), weak proteinuria (<1 g/day), an absence of previous acute rejection and subclinical rejection, and appearance of donor-specific anti-human leukocyte antigen antibodies appear to be the most important criteria in identifying patients for whom conversion to an mTOR inhibitor may improve renal function at 5 years.

Optimising the use of mTOR inhibitors in renal transplantation

Renal transplantation is the treatment of choice for end-stage renal failure. Although advances in immunosuppression have led to improvements in short-term outcomes, graft survival beyond 5 to 10 years has not improved. One of the major causes of late renal allograft failure is chronic allograft nephropathy, a component of which is nephrotoxicity from the use of calcineurin inhibitors (CNIs). In addition, premature patient death is a major limitation of renal transplantation and the major causes are cancer, cardiovascular disease and infection. CNI-free immunosuppressive regimens based on mammalian target of rapamycin (mTOR) inhibitors have been trial led over the last few years and have defined the rational use of these agents. Conversion from a CNI-based to an mTOR-inhibitor-based regimen has been successful at improving renal function for a number of years after conversion, although long-term survival outcomes are still awaited. The studies suggest that the safest and most effective time to convert is between 1 and 6 months after transplant. In addition, mTOR-inhibitor-based regimens have been shown to be associated with lower rates of post-transplant malignancy and less cytomegalovirus infection, which may add further to the appeal of this approach.

Squamous cell carcinoma of the skin: Emerging need for novel biomarkers

The incidence of non-melanoma skin cancers (NMSC) is rising worldwide resulting in demand for clinically useful prognostic biomarkers for these malignant tumors, especially for invasive and metastatic cutaneous squamous cell carcinoma (cSCC). Important risk factors for the development and progression of cSCC include ultraviolet radiation, chronic skin ulcers and immunosuppression. Due to the role of cumulative long-term sun exposure, cSCC is usually a disease of the elderly, but the incidence is also growing in younger individuals due to increased recreational exposure to sunlight. Although clinical diagnosis of cSCC is usually easy and treatment with surgical excision curable, it is responsible for the majority of NMSC related deaths. Clinicians treating skin cancer patients are aware that certain cSCCs grow rapidly and metastasize, but the underlying molecular mechanisms responsible for the aggressive progression of a subpopulation of cSCCs remain incompletely understood. Recently, new molecular markers for progression of cSCC have been identified.

Immunosuppressants in cancer prevention and therapy

Rapalogs such as rapamycin (sirolimus), everolimus, temserolimus, and deforolimus are indicated for the treatment of some malignancies. Rapamycin is the most effective cancer-preventive agent currently known, at least in mice, dramatically delaying carcinogenesis in both normal and cancer-prone murine strains. In addition, rapamycin and everolimus decrease the risk of cancer in patients receiving these drugs in the context of immunosuppressive regimens. In general, the main concern about the use of immunosuppressants in humans is an increased risk of cancer. Given that rapalogs are useful in cancer prevention and therapy, should they be viewed as immunosuppressants or immunostimulators? Or should we reconsider the role of immunity in cancer altogether? In addition to its anti-viral, anti-inflammatory, anti-angiogenic and anti-proliferative effects, rapamycin operates as a gerosuppressant, meaning that it inhibits the cellular conversion to a senescent state (the so-called geroconversion), a fundamental process involved in aging and age-related pathologies including cancer.

Acute GVHD prophylaxis with standard-dose, micro-dose or no MTX after fludarabine/melphalan conditioning

MTX is a standard component of acute GVHD prophylaxis. However, its use can be limited by toxicity. On the basis of disease risk, we prospectively assigned 132 consecutive patients from January 2005 to February 2011 undergoing first allogeneic hematopoietic cell transplant after conditioning with fludarabine and melphalan to acute GVHD prophylaxis with tacrolimus/MTX (TAC/MTX, N=22), TAC/micro-dose MTX/mycophenolate mofetil (TAC/μMTX/MMF, N=78) or TAC/MMF (TAC/MMF, N=32), to optimize acute GVHD prevention and decrease mortality. The median (range) follow-up was 24 (0.8-60) months. The median patient ages (range) were 37 (23-63), 56 (20-68) and 54 (22-68) years (P<0.0001) for TAC/MTX, TAC/μMTX/MMF and TAC/MMF, respectively. The 100-day cumulative incidences of grade III-IV acute GVHD were 19, 23 and 49% (P=0.015), respectively. The cumulative incidences of severe chronic GVHD at 1 year were 38, 29 and 79% (P<0.001), respectively. Regimen-related toxicities were not significantly different among the three prophylaxis regimens. PFS and OS were equivalent between the TAC/MTX and TAC/μMTX/MMF arms despite significantly older patients in the latter arm, and both had superior PFS and OS than the TAC/MMF arm. Acute GVHD prophylaxis with TAC/μMTX/MMF is as effective as TAC/MTX and superior to TAC/MMF.

Epidemiology of post-transplant malignancy in Asian renal transplant recipients: a population-based study

OBJECTIVE

Using Taiwan's National Health Insurance Research Database, this large population-based study was conducted to explore the incidences and risk factors of post-transplant malignancy in Asian renal transplant recipients.

PATIENTS AND METHODS

A total of 642 patients who firstly underwent renal transplant between January 1, 2000 and December 31, 2008 were identified from a 2 million cohort. The primary endpoint was a subsequent hospitalization with a primary diagnosis of malignancy (ICD-9-CM code: 140.xx-239.xx) after renal transplantation. All patients were followed until the occurrence of endpoints or the end of the study (December 31, 2010), whichever came first. Adjusted risks of post-transplant cancer were analyzed using Cox proportional hazards regression model. All models were adjusted for baseline characteristics, comorbid diseases, transplant year, and exposure to immunosuppressive agents.

RESULTS

Among 642 renal transplant patients, 54 cancers (8.4 %) were identified. The median time between transplant and cancer diagnosis was 46.2 (range 8.5-107.4) months. Cancers of kidney and other unspecified urinary organs was the most common cancer sites, accounted for 18.5 % of the malignancies diagnosed. The next most common cancer sites were trachea, bronchus, and lung (14.8 %), bladder (13.0 %), liver and intrahepatic bile ducts (11.1 %), colon (5.6 %), and prostate (5.6 %). Age at transplantation was a statistically significant risk factor of post-transplant cancer in our study. Increased risks of post-transplant cancer were observed in patients who received immunosuppression agents (cyclosporine (HR 1.26, 95 % CI 0.58-2.77, p = 0.5603), tacrolimus (HR 1.99, 95 % CI 0.66-6.00, p = 0.2197), and mycophenolate (HR 1.00, 95 % CI 0.40-2.45, p = 0.9874)) although the estimates were not statistically significant.

CONCLUSIONS

Our population-based cohort study offers additional insight into post-transplant cancers in Asian population. Further studies are warranted to assess the association between specific immunosuppression agents and post-transplant cancers.

Skin cancer in organ transplant recipients

Organ transplant recipients (OTR) are at a significantly increased risk for developing a wide variety of skin cancers, particularly epithelial skin cancer, Merkel cell carcinoma and Kaposi's sarcoma. Melanoma, skin adnexal neoplasm and cutaneous lymphomas are also more common in OTR and may differ in their clinicopathologic presentation from tumors in immunocompetent patients. The accuracy of clinical diagnosis of suspected premalignant and malignant skin lesions in OTR is modest. Therefore, histopathological diagnosis is an essential element for the diagnostic workup of skin cancers and, in addition, provides important information on prognosis. Squamous cell carcinoma and intraepithelial neoplasias (actinic keratosis, squamous cell carcinoma in situ or Bowen's disease) are the most common forms of skin cancer in OTR. The risk of Merkel cell carcinoma and Kaposi's sarcoma is dramatically increased in OTR. Merkel cell carcinoma shows a highly aggressive course. Kaposi's sarcoma tends to spread to extracutaneous sites. Primary cutaneous lymphomas developing after organ transplantation are rare. The spectrum of cutaneous B cell lymphomas in OTR, in particular, differs significantly from that of the general population, with a predominance of Epstein-Barr virus-driven posttransplant lymphoproliferative disorder. This review discusses the clinical and histopathological aspects of skin cancers in OTR, the impact of dermatopathological analysis on prognosis and the understanding of the pathogenesis of these neoplasms.

Recent progress in genetics of aging, senescence and longevity: focusing on cancer-related genes

It is widely believed that aging results from the accumulation of molecular damage, including damage of DNA and mitochondria and accumulation of molecular garbage both inside and outside of the cell. Recently, this paradigm is being replaced by the “hyperfunction theory”, which postulates that aging is caused by activation of signal transduction pathways such as TOR (Target of Rapamycin). These pathways consist of different enzymes, mostly kinases, but also phosphatases, deacetylases, GTPases, and some other molecules that cause overactivation of normal cellular functions. Overactivation of these sensory signal transduction pathways can cause cellular senescence, age-related diseases, including cancer, and shorten life span. Here we review some of the numerous very recent publications on the role of signal transduction molecules in aging and age-related diseases. As was emphasized by the author of the “hyperfunction model”, many (or actually all) of them also play roles in cancer. So these “participants” in pro-aging signaling pathways are actually very well acquainted to cancer researchers. A cancer-related journal such as Oncotarget is the perfect place for publication of such experimental studies, reviews and perspectives, as it can bridge the gap between cancer and aging researchers.

Primary cutaneous posttransplant lymphoproliferative disorders in solid organ transplant recipients: a multicenter European case series

Primary cutaneous posttransplant lymphoproliferative disorders (PTLD) are rare. This retrospective, multicenter study of 35 cases aimed to better describe this entity. Cases were (re)-classified according to the WHO-EORTC or the WHO 2008 classifications of lymphomas. Median interval between first transplantation and diagnosis was 85 months. Fifty-seven percent of patients had a kidney transplant. Twenty-four cases (68.6%) were classified as primary cutaneous T cell lymphoma (CTCL) and 11 (31.4%) as primary cutaneous B cell PTLD. Mycosis fungoides (MF) was the most common (50%) CTCL subtype. Ten (90.9%) cutaneous B cell PTLD cases were classified as EBV-associated B cell lymphoproliferations (including one plasmablastic lymphoma and one lymphomatoid granulomatosis) and one as diffuse large B cell lymphoma, other, that was EBV-negative. Sixteen (45.7%) patients died after a median follow-up of 19.5 months (11 [68.8%] with CTCL [6 of whom had CD30(+) lymphoproliferative disorders (LPD)] and 5 [31.2%] with cutaneous B cell PTLD. Median survival times for all patients, CTCL and cutaneous B cell PTLD subgroups were 93, 93, and 112 months, respectively. Survival rates for MF were higher than those for CD30(+) LPD. The spectrum of primary CTCL in organ transplant recipients (OTR) is similar to that in the general population. The prognosis of posttransplant primary cutaneous CD30(+) LPD is worse than posttransplant MF and than its counterpart in the immunocompetent population. EBV-associated cutaneous B cell LPD predominates in OTR.

[Tumor and transplantation]

Tumor treatment and transplantation-associated with unavoidable mandatory immunosuppression-appear to be unreconcilable opposites. The clinical reality shows, however, that transplantation in many early stage primary tumors is the most effective treatment. The essential immunosuppression after transplantation can however promote tumor recurrence. Immunosuppression also leads to a significant increased rate of de novo tumors-in all organ transplant recipients. However, not all immunosuppressant drugs have the same effect on tumors. In experimental and clinical settings, the class of mTOR inhibitors has a clear antitumoral effect and is recommended as the immunosuppression treatment of choice in patients with increased tumor risk. The purpose of this review is to provide the reader with the scientific background regarding the clinical problem of tumors and transplantation.

Corticosteroid and calcineurin inhibitor sparing regimens in kidney transplantation

Chronic kidney disease is a major public health problem that is associated with increased risks of kidney disease progression, cardiovascular disease and death. Kidney transplantation remains the renal replacement therapy of choice for patients with end-stage kidney disease. Despite impressive strides in short-term allograft survival, there has been little improvement in long-term kidney graft survival, and rates of death with a functioning allograft remain high. Long-term safety profiles of existing immunosuppressive regimens point to a need for continued search for alternative agents. This overview discusses emerging evidence on a few promising therapeutic approaches, juxtaposes conflicting findings and highlights remaining knowledge gaps.

Cancer in the transplant recipient

Malignancy has become one of the three major causes of death after transplantation in the past decade and is thus increasingly important in all organ transplant programs. Death from cardiovascular disease and infection are both decreasing in frequency from a combination of screening, prophylaxis, aggressive risk factor management, and interventional therapies. Cancer, on the other hand, is poorly and expensively screened for; risk factors are mostly elusive and/or hard to impact on except for the use of immunosuppression itself; and finally therapeutic approaches to the transplant recipient with cancer are often nihilistic. This article provides a review of each of the issues as they come to affect transplantation: cancer before wait-listing, cancer transmission from the donor, cancer after transplantation, outcomes of transplant recipients after a diagnosis of cancer, and the role of screening and therapy in reducing the impact of cancer in transplant recipients.

mTOR signaling pathway in penile squamous cell carcinoma: pmTOR and peIF4E over expression correlate with aggressive tumor behavior

PURPOSE

Penile squamous cell carcinoma is a rare neoplasm associated with a high risk of metastasis and morbidity. There are limited data on the role of the mTOR signaling pathway in penile squamous cell carcinoma carcinogenesis and tumor maintenance. We assessed a possible role for mTOR signaling pathway activation as a potential predictive biomarker of outcome and a therapeutic target for penile cancer.

MATERIAL AND METHODS

A cohort of 67 patients diagnosed with invasive penile squamous cell carcinoma from 1987 to 2010 who had known HPV status were selected for study. Tissue microarrays were constructed with 67 primary penile squamous cell carcinomas, matched normal tissues and 8 lymph node metastases. Immunohistochemical staining was performed for p53, pmTOR, pERK, p4E-BP1, eIF4E and peIF4E. Expression was evaluated using a semiquantitative H-score on a scale of 0 to 300.

RESULTS

Expression of pmTOR, p4E-BP1, eIF4E and peIF4E was increased in penile tumors compared with matched adjacent normal tissues, indicating activation of the mTOR signaling pathway in penile tumorigenesis. Over expression of pmTOR, peIF4E and p53 was significantly associated with lymph node disease. peIF4E and p53 also correlated with a poor outcome, including recurrence, metastasis or disease specific death. In contrast, pERK and p4E-BP1 were associated with lower pT stages. pmTOR and intense p53 expression was associated with HPV negative tumors.

CONCLUSIONS

Activation of mTOR signaling may contribute to penile squamous cell carcinoma progression and aggressive behavior. Targeting mTOR or its downstream signaling targets, such as peIF4E, may be a valid therapeutic strategy.

Sirolimus and non-melanoma skin cancer prevention after kidney transplantation: a meta-analysis

BACKGROUND

Whether sirolimus is useful in the prevention of non-melanoma skin cancer (NMSC) remains unclear and we therefore performed this meta-analysis of randomized controlled trials to test the hypothesis that Sirolimus-based immunosuppression is associated with a decrease in NMSC.

METHODS

The main outcomes were NMSC, squamous-cell carcinoma and basal-cell carcinoma. The pooled risk ratio (RR) with its 95% confidence interval (95%CI) were used to assess the effects.

RESULTS

5 randomized trials involving a total of 1499 patients receiving kidney transplantation were included. Patients undergoing Sirolimus-based immunosuppression had much lower risk of NMSC (RR = 0.49, 95%CI 0.32-0.76, P = 0.001). Subgroup analyses by tumor type showed that Sirolimus-based immunosuppression significantly decreased risk of both squamous-cell carcinoma (RR = 0.58, 95%CI 0.43-0.78, P < 0.001) and basal-cell carcinoma (RR = 0.56, 95%CI 0.37-0.85, P = 0.006). The quality of evidence was high for NMSC, and moderate for squamous-cell carcinoma and basal-cell carcinoma. No evidence of publication bias was observed.

CONCLUSION

High quality evidence suggests that Sirolimus-based immunosuppression decreases risk of non-melanoma skin cancer, and Sirolimus has an antitumoral effect among kidney-transplant recipients.

Exploring new frontiers: sirolimus as a pharmacokinetic modulator in advanced cancer patients

The mTOR pathway mediates many biologic functions such as transcriptional and translational control, and is a target for anticancer drug development. mTOR inhibitors, such as sirolimus (SRL), display immunosuppressive and antiproliferative properties, and the use of SRL in kidney transplant recipients reduces the risk of post-transplant cancer. However, its use in advanced cancer patients has not been fully evaluated. The authors review the study by Cohen et al., evaluating the dose for oral, weekly SRL alone or in combination with grapefruit juice or ketoconazole to achieve the desired whole-blood concentration with antitumoral activity. This study demonstrates that SRL can be feasibly administered orally once weekly and displays a similar pharmacokinetic profile compared with other mTOR inhibitors. This study encouraged the use of SRL in advanced cancer patients and can stimulate clinical trials with a larger number of patients, evaluating the role of SRL as a new targeted therapy in cancer patients.

Maintenance immunosuppression in renal transplantation

The need to maintain allograft recipients on immunosuppression is nearly universal. Immunosuppressive agents used in organ transplantation target one or more steps of the host alloimmune response, specifically processes related to CD4-positive T lymphocytes. Calcineurin-inhibitor based steroid-containing regimens have been the mainstay of maintenance immunosuppression over the last two decades. Newer agents have shown efficacy in this role in recent trials with comparable allograft and patient outcomes. These agents have permitted calcineurin-inhibitor minimization and steroid-sparing strategies in selected groups of patients.

Are patients with inflammatory eye disease treated with systemic immunosuppressive therapy at increased risk of malignancy?

The purpose of this study is to review the literature on the risk of malignancy in patients with inflammatory eye disease (IED) treated with systemic immunosuppressive (IS) therapy. Relevant databases in transplant medicine, autoimmune diseases and literature regarding uveitis and scleritis were reviewed. Literature with regards systemic IS therapy in transplant recipients and patients with autoimmune diseases revealed a significant increase in malignancies, especially non-melanocytic skin cancers and lymphomas. Studies of patients with IED were limited in number and scope, with no studies adequately evaluating the incidence of malignancy in these patients. Difficulties associated with the evaluation of the risk of malignancy associated with IS therapy in patients with IED include the heterogeneity of the disease and treatment regimens as well as the low frequency of IED, its variable severity and the lack of adequate long-term follow-up studies. Systemic IS therapy is an important therapeutic option in the treatment of patients with severe IED. A well-designed, comprehensive, multi-centre long-term follow-up study is required to evaluate the risk of malignancy in patients with specific IED diseases treated with defined systemic IS therapy. Until such evidence is available, we recommend the adoption of preventative strategies to help minimise the risk of malignancy in such patients.

The efficacy of tacrolimus and sirolimus in heavily pre-treated unresectable thymic malignancies

BACKGROUND

Thymomas and thymic carcinomas, although uncommon, constitute a significant proportion of anterior mediastinal tumours. Systemic chemotherapy is the mainstay of treatment for inoperable or recurrent disease, but immunosuppressive therapy may provide an alternative treatment strategy.

PATIENTS AND METHODS

We present a series of 18 patients diagnosed with unresectable thymic tumours, of which eight received immunosuppressive therapy following relapse after chemotherapy.

RESULTS

Eight individuals were treated with primary immunotherapy after a median of 3.5 lines of chemotherapy (range 2-6 lines), of which 3 had confirmed myasthenia gravis (MG). After 3 months, 2 patients achieved a radiological partial response and 4 had stable disease. The median time to progression measured 6.8 months (CI 1.4-19.3 months). Two of the 4 patients who progressed on tacrolimus and prednisolone received sirolimus. One of these patients has stable disease (SD) at 21 months, and the other has SD at 3 months.

CONCLUSIONS

Although previous case reports have related tacrolimus therapy with tumour shrinkage in patients with MG-associated invasive thymomas, these data are the first to demonstrate the efficacy of such immunosuppressive agents in a larger cohort of heavily pre-treated patients with thymic tumours. Our experience adds to the limited anecdotal evidence in the literature, and suggests that immunosuppressive agents represent a valuable additional treatment for thymic tumours.

Mechanistic target of rapamycin inhibitors in solid organ transplantation: from benchside to clinical use

PURPOSE OF REVIEW

Here, we review recent advances and new insights in mechanistic target of rapamycin (mTOR) biology (signalling pathway, kidney biology and immune system), and recent clinical data on mTOR inhibitors related to solid organ transplantation.

RECENT FINDINGS

The mTOR pathway is a major integrator of signals governing protein and lipid biosynthesis and growth factor-driven cell cycle progression. Recent findings have emphasized a critical role of mTOR in cellular homeostasis with a crucial role in podocyte function. Beyond CD8(+) and regulatory T-cell control, mTOR protein is involved in critical biological functions of T helper cells or dendritic cells. New specific inhibitors of mTORC1/C2 are available and shed new light on mTOR functions. Finally, clinical trials have better defined the use of mTOR inhibitors and emphasized their role in cancer prevention.

SUMMARY

The mTOR pathway is considered as a key integrator of multiple inputs that drives numerous biological processes in cell biology. mTOR inhibitors are potent immunosuppressive drugs for solid organ transplantation. Newly designed specific inhibitors of mTOR complex 1 and 2 offer promising therapeutic effects and a better understanding of the pathway. Many conditions may benefit from mTOR inhibition for a short period, but tolerance of treatment in a chronic setting remains a major concern.

[What's new in oncology?]

In cutaneous oncology, the year 2012 was marked by the consolidation of earlier results as well as the emergence of new therapeutic perspectives. The consolidated results most notably concern the use of MAP-kinase inhibitors (anti-MEK, anti-BRAF) in the treatment of patients with metastatic melanoma. Vismodegib (an SMO inhibitor), used in the treatment of multiple basocellular carcinomas that are inoperable or that have developed in patients suffering from Gorlin syndrome, has been the subject of publication of large-scale studies. Of the new therapeutic advances, let us mention the use of inhibitors or monoclonal antibodies directed against the PD1 receptor and its ligand PD-L1, the combination of MEK and BRAF inhibitors in the treatment of metastatic melanoma, and treatment in adjuvant situations with these same inhibitors. Beyond these significant advances that must be credited to cutaneous oncology, new questions are emerging relative to the side effects observed with these targeted therapies. The onset of multiple epidermoid carcinomas or primary melanomas treated with BRAF inhibitors is a striking illustration of the paradoxes arising from the clinical transfer of scientific progress. The intellectual perspectives are therefore numerous. It is hoped that this work will succeed in making these innovative drugs available to the patients who will have contributed to their development through their participation in clinical trials.

American Society of Nephrology Quiz and Questionnaire 2012: Transplantation

Presentation of the Nephrology Quiz and Questionnaire has become an annual tradition at the meetings of the American Society of Nephrology. It is a very popular session, as judged by consistently large attendance. Members of the audience test their knowledge and judgment on a series of case-oriented questions prepared and discussed by experts. They can also compare their answers in real time, using audience response devices, to those of program directors of nephrology training programs in the United States, acquired through an Internet-based questionnaire. Topics presented here include fluid and electrolyte disorders, transplantation, and ESRD and dialysis. Cases representing each of these categories, along with single-best-answer questions, were prepared by a panel of experts (Drs. Palmer, Fervenza, Brennan, and Mehrotra, respectively). The correct and incorrect answers were briefly discussed after the audience responses, and the results of the questionnaire were displayed. This article recapitulates the session and reproduces its educational value for a larger audience--that of the readers of the Clinical Journal of the American Society of Nephrology. Have fun.

Two-year randomized controlled prospective trial converting treatment of stable renal transplant recipients with cutaneous invasive squamous cell carcinomas to sirolimus

PURPOSE

In light of the significant morbidity and mortality of cutaneous invasive squamous cell carcinomas (SCCs) in renal transplant recipients, we investigated whether conversion to sirolimus-based immunosuppression from standard immunosuppression could diminish the recurrence rate of these skin cancers.

PATIENTS AND METHODS

In a 2-year randomized controlled trial, 155 renal transplant recipients with at least one biopsy-confirmed SCC were stratified according to age (< 55 v ≥ 55 years) and number of previous SCCs (one to nine v ≥ 10) and randomly assigned to conversion to sirolimus (n = 74) or continuation of their original immunosuppression (n = 81). Development of a new SCC within 2 years after random assignment was the primary end point.

RESULTS

After 2 years of follow-up, the risk reduction of new SCCs in the multivariable analysis was not significant, with a hazard ratio (HR) of 0.76 (95% CI, 0.48 to 1.2; P = .255), compared with a non-sirolimus-based regimen. After the first year, there was a significant 50% risk reduction, with an HR of 0.50 (95% CI, 0.28 to 0.90; P = .021) for all patients together and an HR of 0.11 (95% CI, 0.01 to 0.94; P = .044) for patients with only one previous SCC. The tumor burden of SCC was reduced during the 2-year follow-up period in those receiving sirolimus (0.82 v 1.38 per year; HR, 0.51; 95% CI, 0.32 to 0.82; P = .006) if adjusted for the number of previous SCCs and age. Twenty-nine patients stopped taking sirolimus because of various adverse events.

CONCLUSION

Conversion to sirolimus-based immunosuppression failed to show a benefit in terms of SCC-free survival at 2 years.

Malignant epithelial tumors: Part II. Therapy and prevention

A multitude of surgical and non-surgical therapies are available to treat malignant epithelial tumors of the skin. The article summarizes the current treatment options for basal cell carcinoma, squamous cell carcinoma and keratoacanthoma. Moreover, the possibilities of primary and secondary prevention for high-risk patients are reviewed. The decision about the best therapeutic option depends on location, age, and general health of the patient as well as the risk of tumor recurrence.

Inhibitors of mTOR and risks of allograft failure and mortality in kidney transplantation

Data on long-term outcomes of users of inhibitors of the mammalian target of rapamycin (mTORI) are lacking in kidney transplantation. In an analysis of 139 370 US kidney transplant recipients between 1999 through 2010, we compared clinical outcomes among users of mTORIs versus calcineurin inhibitors (CNI) in their primary immunosuppresive regimen. During the first 2 years posttransplantation, primary use of mTORIs without CNIs (N = 3237) was associated with greater risks of allograft failure and death compared with a CNI-based regimen (N = 125 623); the hazard ratio (HR) of the composite outcome ranged from 3.67 (95% confidence interval [CI], 3.12-4.32) after discharge to 1.40 (95% CI 1.26-1.57) by year 2. During years 2-8, primary use of mTORIs without CNIs was independently associated with greater risks of death (HR 1.25; 95% CI, 1.11-1.41) and the composite (HR 1.17; 95%CI, 1.08-1.27) in fully adjusted analyses. The results were qualitatively unchanged in subgroups defined by medical history, immunological risk and clinical course during the index transplant hospitalization. In a propensity-score matched cohort, use of mTORIs was associated with significantly worse outcomes during the first 2 years and greater risks of death (HR 1.21; 95% CI, 1.05-1.39) and the composite (HR 1.18; 95% CI, 1.08-1.30) in years 2-8. Compared with CNI-based regimens, use of an mTORI-based regimen for primary immunosuppression in kidney transplantation was associated with inferior recipient survival.

Update on the long-term complications of renal transplantation

INTRODUCTION

Powerful immunosuppressive regimens have reduced rejection risk, leading to an expanding cohort of long-term kidney transplant recipients who are likely to encounter practitioners in other specialties.

SOURCES OF DATA

Key review papers and primary literature identified through searches of PubMed, Google Scholar and Medline.

AREAS OF AGREEMENT

Death from cardiovascular disease and malignancy remain the chief causes of transplant loss. Risk factors and phenotypes for these differ from the general population.

AREAS OF CONTROVERSY

Many guidelines for renal transplant recipients are based on extrapolation from studies on non-transplant cohorts and may not be appropriate. Emerging studies demonstrate that established interventions in the general population are less efficacious in transplant recipients.

GROWING POINTS

The influence of immunosuppression on the development of complications.

AREAS TIMELY FOR DEVELOPING RESEARCH

Markers to guide individualized optimal immunosuppression and predict the development of complications would allow for targeted early intervention.

Dietary immunosuppressants do not enhance UV-induced skin carcinogenesis, and reveal discordance between p53-mutant early clones and carcinomas

Immunosuppressive drugs are thought to cause the dramatically increased risk of carcinomas in sun-exposed skin of organ transplant recipients. These drugs differ in local effects on skin. We investigated whether this local impact is predictive of skin cancer risk and may thus provide guidance on minimizing the risk. Immunosuppressants (azathioprine, cyclosporine, tacrolimus, mycophenolate mofetil, and rapamycin) were assessed on altering the UV induction of apoptosis in human skin models and of p53 mutant cell clones (putative tumor precursors) and ensuing skin carcinomas (with mutant p53) in the skin of hairless mice. Rapamycin was found to increase apoptosis (three-fold), whereas cyclosporine decreased apoptosis (three-fold). Correspondingly, a 1.5- to five-fold reduction (P = 0.07) or a two- to three-fold increase (P < 0.001) was found in cell clusters overexpressing mutant p53 in chronically UV-exposed skin of mice that had been fed rapamycin or cyclosporine, respectively. Deep sequencing showed, however, that the allelic frequency (∼5%) of the hotspot mutations in p53 (codons 270 and 275) remained unaffected. The majority of cells with mutated p53 seemed not to overexpress the mutated protein. Unexpectedly, none of the immunosuppressants admixed in high dosages to the diet accelerated tumor development, and cyclosporine even delayed tumor onset by approximately 15% (P < 0.01). Thus, in contrast to earlier findings, the frequency of p53-mutant cells was not predictive of the incidence of skin carcinoma. Moreover, the lack of any accelerative effect on tumor development suggests that immunosuppressive medication is not the sole cause of the dramatic increase in skin cancer risk in organ transplant recipients.

Melanoma in organ transplant recipients: incidence, outcomes and management considerations

The incidence of melanoma continues to increase year on year. With better surgical techniques and medical management, greater numbers of organ transplants are being performed annually with much longer graft survival. The authors review our current understanding of the incidence of melanoma amongst organ transplant recipients, outcomes compared to the immunocompetent population, and management strategies in this burgeoning group.

[Non oncologic applications of molecular targeted therapies]

Significant improvements in the knowledge of cancer biology have permitted the development of new molecular targeted therapies. Meanwhile, a better understanding of the physiology of various non-cancerous diseases has allowed developing these agents in other areas. This review intends to illustrate these perspectives through examples corresponding to different strategies of molecular-targeted therapies : use of a monoclonal antibody binding a receptor (rituximab and rheumatoid arthritis) or a ligand (bevacizumab and age-related macular degeneration), tyrosine kinase inhibitor (imatinib and systemic sclerosis) or inhibitor of cytoplasmic signal transduction pathways (immunosuppressive and antiproliferative effects of mammalian target of rapamycin [mTOR] inhibitors). Clinical results can draw today what could become molecular medicine of tomorrow.

An evaluation of sirolimus in renal transplantation

INTRODUCTION

Sirolimus is a powerful antiproliferative immunosuppressive drug approved for the prevention of kidney allograft rejection. By its unique mechanism of action, sirolimus provides a multitude of clinical potential and has been used effectively in different drug combinations. Extensive experience has been gained regarding the best timing of its application, side effect profile and potential benefits and limitations compared with other immunosuppressive drugs.

AREAS COVERED

The authors evaluate the recent experience with sirolimus in kidney transplantation. Pivotal randomized controlled trials were used to provide an overview with special attention to pharmacokinetic and dynamic aspects of sirolimus, its current clinical use as well as perspectives for its future role.

EXPERT OPINION

Sirolimus enriches the possibilities of immunosuppressive therapies after renal transplantation. Beneficial effects toward kidney function by allowing CNI sparing, lower incidence of malignancies and less viral infections have been suggested. Sirolimus should be used cautiously in de novo patients for reasons of wound healing. An early conversion to a sirolimus-based CNI-free regimen has shown promising results, whereas late conversion is more challenging. Finally, sirolimus-associated side effects are causing tolerability concerns and frequent discontinuations. Future research should aim to better define the therapeutic window and those patients most likely to benefit.