Post-transplantation malignancies: here today, gone tomorrow? Nat Rev Clin Oncol. 2015;12:705-717. [PMID: 26483298 DOI: 10.1038/nrclinonc.2015.186]

Cancer mortality among solid organ transplant recipients: A systematic review and meta-analysis

OBJECTIVES

To evaluate the cancer mortality risk among solid organ transplant recipients through a systematic review and meta-analysis.

METHODS

Systematic searches were conducted in PubMed (starting from 1965), ISI Web of Science (starting from 1900), MEDLINE (starting from 1976), and Scopus (starting from 1968) from the inception of each database until July 15, 2024. Studies published in English reporting at least one type of cancer mortality risk among recipients of any type of solid organ transplantation were included. The main outcomes were the standardized mortality ratio (SMR) for cancer mortality in transplant recipients compared to the general population, and the hazard ratio (HR) for cancer mortality in transplant recipients versus cancer patients without prior transplantation.

RESULTS

Solid organ transplant recipients had a 2.06-fold increased cancer mortality risk (SMR, 2.06 [95 % CI, 1.56-2.71]) than the general population. Risks were higher in kidney (SMR 1.92 [95 % CI: 1.30-2.84]), liver (SMR 3.07 [95 % CI: 1.80-5.24]), and lung/heart (SMR 4.87 [95 % CI: 3.33-7.12]) transplant recipients. Cancer patients with prior transplantation had a 1.47-fold increased cancer mortality risk (HR 1.47 [95 % CI: 1.29-1.68]) than those without. East Asia female transplant recipients exhibited higher mortality risks from breast, ovarian, cervix and uterus cancers than those from other regions (SMR 3.13 [95 % CI: 1.93-5.07] vs. 1.16 [95 % CI: 0.88-1.53], P < 0.01).

CONCLUSIONS

Solid organ transplant recipients face significantly higher cancer mortality risks than the general population, highlighting the need for targeted cancer screening and interventions, especially for female solid organ transplant recipients from East Asia.

Rapamycin inhibits B16 melanoma cell viability invitro and invivo by inducing autophagy and inhibiting the mTOR/p70‑S6k pathway

Rapamycin is an immunosuppressant that has been shown to prevent tumor growth following organ transplantation. However, its exact mode of antitumor action remains unknown. The present study used the B16-F10 (B16) murine melanoma model to explore the antitumor mechanism of rapamycin, and it was revealed that rapamycin reduced B16 cell viability in vitro and in vivo. In addition, in vitro and in vivo, the results of western blotting showed that rapamycin reduced Bcl2 expression, and enhanced the protein expression levels of cleaved caspase 3 and Bax, indicating that it can induce the apoptosis of B16 melanoma cells. Furthermore, the results of cell cycle analysis and western blotting showed that rapamycin induced B16 cell cycle arrest in the G1 phase, based on the reduction in the protein expression levels of CDK1, cyclin D1 and CDK4, as well as the increase in the percentage of cells in G1 phase. Rapamycin also significantly increased the number of autophagosomes in B16 melanoma cells, as determined by transmission electron microscopy. Furthermore, the results of RT-qPCR and western blotting showed that rapamycin upregulated the protein expression levels of microtubule-associated protein light chain 3 (LC3) and Beclin-1, while downregulating the expression of p62 in vitro and in vivo, thus indicating that rapamycin could trigger cellular autophagy. The present study revealed that rapamycin in combination with chloroquine (CQ) further increased LC3 expression compared with that in the CQ group, suggesting that rapamycin induced an increase in autophagy in B16 cells. Furthermore, the results of western blotting showed that rapamycin blocked the phosphorylation of p70 ribosomal S6 kinase (p70-S6k) and mammalian target of rapamycin (mTOR) proteins in vitro and in vivo, thus suggesting that rapamycin may exert its antitumor effect by inhibiting the phosphorylation of the mTOR/p70-S6k pathway. In conclusion, rapamycin may inhibit tumor growth by inducing cellular G1 phase arrest and apoptosis. In addition, rapamycin may exert its antitumor effects by inducing the autophagy of B16 melanoma cells in vitro and in vivo, and the mTOR/p70-S6k signaling pathway may be involved in this process.

Tacrolimus Drug Exposure Level and Smoking Are Modifiable Risk Factors for Early De Novo Malignancy After Liver Transplantation for Alcohol-Related Liver Disease

De novo malignancy (DNM) is the primary cause of mortality after liver transplantation (LT) for alcohol-related liver disease (ALD). However, data on risk factors for DNM development after LT are limited, specifically in patients with ALD. Therefore, we retrospectively analyzed all patients transplanted for ALD at our center before October 2016. Patients with a post-LT follow-up of <12 months, DNM within 12 months after LT, patients not on tacrolimus in the 1st year post-LT, and unknown smoking habits were excluded. Tacrolimus drug exposure level (TDEL) was calculated by area under the curve of trough levels in the 1st year post-LT. 174 patients received tacrolimus of which 19 (10.9%) patients developed a DNM between 12 and 60 months post-LT. Multivariate cox regression analysis identified TDEL [HR: 1.710 (1.211-2.414); p = 0.002], age [1.158 (1.076-1.246); p < 0.001], number of pack years pre-LT [HR: 1.021 (1.004-1.038); p = 0.014] and active smoking at LT [HR: 3.056 (1.072-8.715); p = 0.037] as independent risk factors for DNM. Tacrolimus dose minimization in the 1st year after LT and smoking cessation before LT might lower DNM risk in patients transplanted for ALD.

RapaLink-1 outperforms rapamycin in alleviating allogeneic graft rejection by inhibiting the mTORC1-4E-BP1 pathway in mice

Inhibition of mammalian target of rapamycin (mTOR), which is a component of both mTORC1 and mTORC2, leads to clinical benefits for organ transplant recipients. Pathways to inhibit mTOR include strengthening the association of FKBP12-mTOR or competing with ATP at the active site of mTOR, which have been applied to the design of first- and second-generation mTOR inhibitors, respectively. However, the clinical efficacy of these mTOR inhibitors may be limited by side effects, compensatory activation of kinases and attenuation of feedback inhibition of receptor expression. A new generation of mTOR inhibitors possess a core structure similar to rapamycin and covalently link to mTOR kinase inhibitors, resulting in moderate selectivity and potent inhibition of mTORC1. Since the immunosuppressive potential of this class of compounds remains unknown, our goal is to examine the therapeutic efficacy of a third-generation mTOR inhibitor in organ transplantation. In this study, RapaLink-1 outperformed rapamycin in inhibiting T-cell proliferation and significantly prolonged graft survival time. Mechanistically, the ameliorated rejection induced by RapaLink-1 is associated with a reduction in p-4E-BP1 in T cells, resulting in an elevation in Treg cells alongside a decline in Th1 and Th17 cells. For the first time, these studies demonstrate the effectiveness of third-generation mTOR inhibitors in inhibiting allograft rejection, highlighting the potential of this novel class of mTOR inhibitors for further investigation.

Induced Coma, Death, and Organ Transplantation: A Physiologic, Genetic, and Theological Perspective

In the clinic, the death certificate is issued if brain electrical activity is no longer detectable. However, recent research has shown that in model organisms and humans, gene activity continues for at least 96 h postmortem. The discovery that many genes are still working up to 48 h after death questions our definition of death and has implications for organ transplants and forensics. If genes can be active up to 48 h after death, is the person technically still alive at that point? We discovered a very interesting parallel between genes that were upregulated in the brain after death and genes upregulated in the brains that were subjected to medically-induced coma, including transcripts involved in neurotransmission, proteasomal degradation, apoptosis, inflammation, and most interestingly, cancer. Since these genes are involved in cellular proliferation, their activation after death could represent the cellular reaction to escape mortality and raises the question of organ viability and genetics used for transplantation after death. One factor limiting the organ availability for transplantation is religious belief. However, more recently, organ donation for the benefit of humans in need has been seen as “posthumous giving of organs and tissues can be a manifestation of love spreading also to the other side of death”.

Hand transplantation: can we balance the risks and benefits?

Asking 'can we balance the risks and benefits?' implies that a quantification of both risk and benefit in hand transplantation (here the terms hand transplant and hand transplantation refer to allotransplantation of the human hand or hand and part or all of the upper limb or limbs) is possible. Despite all we have learned in recent years about hand transplantation, much remains unknown. Even if reliable methods for quantification of risk and benefit were available, fundamental issues relating to effective communication across the gulf of lived experience between the (presumably) handed surgeon and the handless patient remain. Inherent complexities mean some consider hand transplantation an unsolved problem, but we believe the medical and technical considerations fall within the ambit of a competent multidisciplinary team, and that psychosocial and ethical challenges are open to management through robust frameworks for assessment and decision making, underpinned by an extended period of assessment and dialogue, with candid acknowledgement where uncertainty remains. This respects the patient's autonomy while addressing the need for a prolonged period of informing consent.Level of evidence: V.

Skin cancer in solid organ transplant recipients: still an open problem

In the last two decades, the optimization of organ preservation and surgical techniques, and the personalized immunosuppression have reduced the rate of acute rejections and early post-transplant complications. However, long-term graft survival rates have not improved over time, and evidence suggest a role of chronic calcineurin inhibitor toxicity in this failure. Solid organ transplant recipients may develop chronic dysfunction/damage and several comorbidities, including post-transplant malignancies. Skin cancers, mostly non-melanoma skin cancers (squamous cell carcinoma and basal cell carcinoma), are the most common malignancies in Caucasian solid organ transplant recipients. Several factors, together with immunosuppression, may contribute to the susceptibility for skin cancers which, although often treatable, could be associated with a much higher mortality rate than in the general population. The rapid identification and treatment (including reduction of immunosuppression and early surgical treatments) have an important role to avoid an aggressive behavior of these malignancies. Organ transplant recipients with a history of skin cancer should be followed closely for developing new and metastatic lesions. Additionally, patient education on the daily use of sun-protective measures and the recognition of the early signs (self-diagnosis) of coetaneous malignancies are useful preventive measures. Finally, clinicians should make themselves aware of the problem and build, in every clinical follow-up center, collaborative network involving transplant clinicians, dermatologists and surgeons who should work together to easily identify and rapidly treat these complications. In this review, we discuss the current literature regarding the epidemiology, risk factors, diagnosis, preventive strategies and treatments of skin cancer in organ transplantation.

Artificial Intelligence: Present and Future Potential for Solid Organ Transplantation

Artificial intelligence (AI) refers to computer algorithms used to complete tasks that usually require human intelligence. Typical examples include complex decision-making and- image or speech analysis. AI application in healthcare is rapidly evolving and it undoubtedly holds an enormous potential for the field of solid organ transplantation. In this review, we provide an overview of AI-based approaches in solid organ transplantation. Particularly, we identified four key areas of transplantation which could be facilitated by AI: organ allocation and donor-recipient pairing, transplant oncology, real-time immunosuppression regimes, and precision transplant pathology. The potential implementations are vast—from improved allocation algorithms, smart donor-recipient matching and dynamic adaptation of immunosuppression to automated analysis of transplant pathology. We are convinced that we are at the beginning of a new digital era in transplantation, and that AI has the potential to improve graft and patient survival. This manuscript provides a glimpse into how AI innovations could shape an exciting future for the transplantation community.

The effect of immunosuppressive therapy after liver transplantation on activities of daily living and fear of death during the COVID-19 pandemic

BACKGROUND

In our study, we aimed to investigate the effect of immunosuppressive therapy after liver transplantation on activities of daily living and fear of death during the COVID-19 pandemic.

METHODS

This study was conducted as a cross-sectional study with the participation of 213 liver transplant patients hospitalized in the liver transplant center of a university hospital. The data analysis was performed with IBM SPSS (Statistical Package for the Social Sciences) Statistics 25.

RESULTS

Katz's Activities of Daily Living (ADL) were semi-independent and the total score was 11.07 ± 1.59, and the Death Attitude Profile-Revised (DAP-R) total score was 152.23 ± 5.34. It was determined that the DAP-R score was around 150 points in the minimum and maximum score ranges of Katz ADL after liver transplantation.

CONCLUSIONS

High fear of death threatens resilience and can make patients feel lonely, helpless, sad, abandoned and stressed. Clinicians should spend more time with their patients.

The effect of immunosuppression therapy on activities of daily living and comfort level after liver transplantation

OBJECTIVES

This study was carried out to investigate the effect of immunosuppression therapy on activities of daily living and comfort level after liver transplantation.

MATERIALS AND METHODS

This study was conducted in a descriptive and correlational type with the participation of 148 liver transplant patients hospitalized in the liver transplant center of a university hospital. Personal Information Form, Katz Activities of Daily Living Scale and General Comfort Questionnaire were used in data collection. The data analysis was performed with IBM SPSS (Statistical Package for the Social Sciences) Statistics 25.

RESULTS

According to the results obtained from the study, it was determined that 31.1% of the patients were 58 years old and over, 20.9% of them were between 48- and 57 years old, and 81.8% of them were male. It was found that 61.5% of the patients were between the 11th and 21st days after transplantation and 26.4% of them were given oxygen with a non-invasive catheter. It was determined that the patients were semi-independent in activities of daily living and had a moderate comfort level.

CONCLUSIONS

It is not always possible for liver transplant patients to effectively deal with their condition. The low comfort level and quality of life of patients who have undergone liver transplantation should be noticed, and social, economic and psychological support should be provided.

Implications of cancer prior to and after heart transplantation

Cancer and cardiovascular disease share many risk factors. Due to improved survival of patients with cancer, the cohort of cancer survivors with heart failure referred for heart transplantation (HT) is growing. Specific considerations include time interval between cancer treatment and HT, risk for recurrence and risk for de novo malignancy (dnM). dnM is an important cause of post-HT morbidity and mortality, with nearly a third diagnosed with malignancy by 10 years post-HT. Compared with the age-matched general population, HT recipients have an approximately 2.5-fold to 4-fold increased risk of developing cancer. HT recipients with prior malignancy show variable cancer recurrence rates, depending on years in remission before HT: 5% recurrence if >5 years in remission, 26% recurrence if 1-5 years in remission and 63% recurrence if <1 year in remission. A myriad of mechanisms influence oncogenesis following HT, including reduced host immunosurveillance from chronic immunosuppression, influence of oncogenic viruses, and the cumulative intensity and duration of immunosuppression. Conversely, protective factors include acyclovir prophylaxis, use of proliferation signal inhibitors (PSI) and female gender. Management involves reducing immunosuppression, incorporating a PSI for immunosuppression and heightened surveillance for allograft rejection. Cancer treatment, including immunotherapy, may be cardiotoxic and lead to graft failure or rejection. Additionally, there exists a competing risk to reduce immunosuppression to improve cancer outcomes, which may increase risk for rejection. A multidisciplinary cardio-oncology team approach is recommended to optimise care and should include an oncologist, transplant cardiologist, transplant pharmacist, palliative care, transplant coordinator and cardio-oncologist.

Management of the kidney transplant patient with Cancer: Report from a Multidisciplinary Consensus Conference

INTRODUCTION

Cancer is the second most common cause of mortality and morbidity in Kidney Transplant Recipients (KTRs). Immunosuppression can influence the efficacy of cancer treatment and modification of the immunosuppressive regimen may restore anti-neoplastic immune responses improving oncologic prognosis. However, patients and transplant physicians are usually reluctant to modify immunosuppression, fearing rejection and potential graft loss. Due to the lack of extensive and recognised data supporting how to manage the immunosuppressive therapy in KTRs, in the context of immunotherapy, chemotherapy, radiotherapy and loco-regional treatments, a Consensus Conference was organised under the auspices of the European Society of Organ Transplantation and the Italian Society of Organ Transplantation. The conference involved a multidisciplinary group of transplant experts in the field across Europe.

METHODS

The overall process included a) the formulation of 12 specific questions based on the PICO methodology, b) systematic literature review and summary for experts for each question, c) a two-day conference celebration and the collection of experts' agreements. The conference was articulated in three sessions: "Immunosuppressive therapy and immunotherapy", "Systemic therapy", "Integrated Therapy", while the final experts' agreement was collected with a televoting procedure and defined according to the majority criterion.

RESULTS

Twenty-six European experts attended the conference and expressed their vote. A total of 14 statements were finally elaborated and voted. Strong agreement was found for ten statements, moderate agreement for two, moderate disagreement for one and uncertainty for the last one.

CONCLUSIONS

The consensus statements provide guidance to transplant physicians caring for kidney transplant recipients with cancer and indicate key aspects that need to be addressed by future clinical research.

Predictive Factors of De Novo Malignancies After Living-Donor Liver Transplantation: A Single-Center Experience

BACKGROUND

De novo malignancies are a major reason of long-term mortalities after liver transplantation. However, they usually receive minimal attention from most health care specialists. The current study aims to evaluate our experience of de novo malignancies after living-donor liver transplantation (LDLT).

METHODS

We reviewed the data of patients who underwent LDLT at our center during the period between May 2004 and December 2018.

RESULTS

During the study period, 640 patients underwent LDLT. After a mean follow-up period of 41.2 ± 25.8 months, 15 patients (2.3%) with de novo malignancies were diagnosed. The most common de novo malignancies were cutaneous cancers (40%), post-transplantation lymphoproliferative disorders (13.3%), colon cancers (13.3%), and breast cancers (13.3%). Acute cellular rejection (ACR) episodes occurred in 10 patients (66.7%). Mild ACR occurred in 8 patients (53.3%), and moderate ACR occurred in 2 patients (13.3%). All patients were managed with aggressive cancer treatment. The mean survival after therapy was 40.8 ± 26.4 months. The mean overall survival after LDLT was 83.9 ± 52.9 months. Twelve patients (80%) were still alive, and 3 mortalities (20%) occurred. The 1-, 5-, and 10-year overall survival rates after LDLT were 91.7%, 91.7%, and 61.1%, respectively. On multivariate regression analysis, smoking history, operation time, and development of ACR episodes were significant predictors of de novo malignancy development.

CONCLUSIONS

Liver transplant recipients are at high risk for the development of de novo malignancies. Early detection and aggressive management strategies are essential to improving the recipients' survival.

Regression of Lung Squamous Cell Carcinoma after the Withdrawal of Cyclosporin A Combined with Pirfenidone Treatment in a Patient with Idiopathic Pulmonary Fibrosis

A 72-year-old man was treated with prednisolone and cyclosporine A for idiopathic pulmonary fibrosis. A nodule with a diameter of 19 mm was found in the right lung and diagnosed as lung squamous cell carcinoma. Anti-cancer treatments were not performed because of the presence of advanced interstitial pneumonia and chronic respiratory failure. Cyclosporine A was tapered to avoid suppression of anti-tumor immunity, and pirfenidone was initiated. Within 2 months, the tumor had shrunk to 10 mm in diameter and remained regressed for 9 months. This is the first report of a non-hematologic solid organ tumor responding to the discontinuation of immunosuppressants.

Evidence of BK Polyomavirus Infection in Urothelial but not Renal Tumors from a Single Center Cohort of Kidney Transplant Recipients

Emerging evidence indicates that reactivation of BK polyomavirus (BKPyV) in the kidney and urothelial tract of kidney transplant recipients (KTRs) may be associated with cancer in these sites. In this retrospective study of a single center cohort of KTRs (n = 1307), 10 clear cell renal cell carcinomas and 5 urinary bladder carcinomas were analyzed from 15 KTRs for the presence of BKPyV infection through immunohistochemistry and fluorescent in situ hybridization (FISH). Three of these patients had already exhibited biopsy-proven polyomavirus-associated nephropathies (PyVAN). Although the presence of BKPyV large-T antigen was evident in the urothelium from a kidney removed soon after PyVAN diagnosis, it was undetectable in all the formalin-fixed and paraffin-embedded (FFPE) blocks obtained from the 10 kidney tumors. By contrast, large-T antigen (LT) labeling of tumor cells was detected in two out of five bladder carcinomas. Lastly, the proportion of BKPyV DNA-FISH-positive bladder carcinoma nuclei was much lower than that of LT-positive cells. Taken together, our findings further strengthen the association between BKPyV reactivation and cancer development in KTRs, especially bladder carcinoma.

Mortality from cancer is not increased in elderly kidney transplant recipients compared to the general population: a competing risk analysis

BACKGROUND

The impact of cancer on death of elderly kidney transplant recipients has been extensively investigated, but with conflicting results. Unlike their younger counterparts, in elderly kidney transplant recipients cardiovascular and infectious disease may outweigh cancer in causing the patient's death.

METHODS

Using competing risk analysis on a large retrospective cohort of kidney transplant recipients, we estimated the cause-specific cumulative incidence and hazard of death in different age categories and calculated standardized mortality ratios (SMRs) to compare mortality rates with the general population.

RESULTS

Six thousand seven hundred eighty-nine kidney transplant recipients were followed-up for a median of 9 years. Ten years after transplantation, in transplant recipients aged 20-39, 40-59, and 60+, the cumulative incidence of cancer-related death was 0.6 (95% confidence interval [CI]: 0.3-1.0), 2.9 (2.3-3.6) and 5.3% (3.5-7.5), whereas the SMR was 9.1 (5.5-15.0), 2.0 (1.6-2.5), and 0.8 (0.6-1.0), respectively. At variance with young recipients, the hazard and the cumulative incidence of cardiovascular-related death in elderly recipients was well above that of cancer-related death.

CONCLUSIONS

Relative to the general population, cancer-related death is increased in young but not in elderly kidney transplant recipients because of the more marked increased incidence of competing cause of death in the latter category.

Treatment options for localised renal cell carcinoma of the transplanted kidney

Currently, there is no consensus among the transplant community about the treatment of renal cell carcinoma (RCC) of the transplanted kidney. Until recently, graftectomy was universally considered the golden standard, regardless of the characteristics of the neoplasm. Due to the encouraging results observed in native kidneys, conservative options such as nephron-sparing surgery (NSS) (enucleation and partial nephrectomy) and ablative therapy (radiofrequency ablation, cryoablation, microwave ablation, high-intensity focused ultrasound, and irreversible electroporation) have been progressively used in carefully selected recipients with early-stage allograft RCC. Available reports show excellent patient survival, optimal oncological outcome, and preserved renal function with acceptable complication rates. Nevertheless, the rarity and the heterogeneity of the disease, the number of options available, and the lack of long-term follow-up data do not allow to adequately define treatment-specific advantages and limitations. The role of active surveillance and immunosuppression management remain also debated. In order to offer a better insight into this difficult topic and to help clinicians choose the best therapy for their patients, we performed and extensive review of the literature. We focused on epidemiology, clinical presentation, diagnostic work up, staging strategies, tumour characteristics, treatment modalities, and follow-up protocols. Our research confirms that both NSS and focal ablation represent a valuable alternative to graftectomy for kidney transplant recipients with American Joint Committee on Cancer stage T1aN0M0 RCC. Data on T1bN0M0 lesions are scarce but suggest extra caution. Properly designed multi-centre prospective clinical trials are warranted.

Immunosuppression following organ transplantation. Part 2: complications and their management

Advances in the care of patients who have had a solid organ transplant has led to a growing population of post-transplant patients, who are also living for longer. As a result of their longer life expectancy, transplant recipients often face a multitude of challenges, including optimising their immunosuppressive regimens and managing potential complications. Life-threatening infections, malignancies, and organ-specific toxicities are the complications post-transplant patients commonly encounter and these complications are often associated with increased morbidity and mortality, adverse graft functioning and survival, profound impairment in the patient's quality of life, and significant healthcare burden. This article, the second of two parts, gives an overview of the issues involved in the care of patients who are receiving immunosuppressants. The common complications encountered by post-transplant patients are discussed and their assessment, management, prevention and treatment explored.

How safe are organs from deceased donors with neoplasia? The results of the Italian Transplantation Network

Guidelines for donor selection have changed to expand the donor pool, considering potential donors affected by a neoplasm. Aim of this retrospective study is to look at the use of organs from donors with a current or history of neoplasm within the Italian Transplant Network. Data, collected and validated by Italian National Health Institute for the time interval 2006-2015, have been reviewed retrospectively by mean of multivariable pivot tables. Donors with neoplasia represented about 5% of all donors, resulting in about 4% of all transplants. Donors presented a benign neoplasm in 29.08% of cases, a malignancy with variable risk of transmission in 69.75% while in 1.34% the nature of neoplasm could not be assessed. Considering all procedures, rate of transmission of a malignancy was 0.03% (10 cases) of all 29858 transplants of the time interval. Notably, cases of transmission were not from donors of this pool, but from donors that, according to our protocols, had no elements of suspect at time of donation. As recipient safety is always the priority and as guidelines have set exclusion criteria for donors with some specific types of malignancy, these results show that use of this type of donors is safe and improve organ pool. Furthermore represent basis for improvement and standardization of donor assessment protocols suggesting that efforts in data collection systems, to produce complete and homogeneous data, are mandatory.

Mastomys Species as Model Systems for Infectious Diseases

Replacements of animal models by advanced in vitro systems in biomedical research, despite exceptions, are currently still not satisfactory in reproducing the whole complexity of pathophysiological mechanisms that finally lead to disease. Therefore, preclinical models are additionally required to reflect analogous in vivo situations as found in humans. Despite proven limitations of both approaches, only a combined experimental arrangement guarantees generalizability of results and their transfer to the clinics. Although the laboratory mouse still stands as a paradigm for many scientific discoveries and breakthroughs, it is mandatory to broaden our view by also using nontraditional animal models. The present review will first reflect the value of experimental systems in life science and subsequently describes the preclinical rodent model Mastomys coucha that-although still not well known in the scientific community-has a long history in research of parasites, bacteria, papillomaviruses and cancer. Using Mastomys, we could recently show for the first time that cutaneous papillomaviruses-in conjunction with UV as an environmental risk factor-induce squamous cell carcinomas of the skin via a "hit-and-run" mechanism. Moreover, Mastomys coucha was also used as a proof-of-principle model for the successful vaccination against non-melanoma skin cancer even under immunosuppressive conditions.

Etiology of increased cancer incidence after solid organ transplantation

Over the past decades, there has been an encouraging increase in survival after solid organ transplantation. However, with longer life spans, more transplant recipients are at risk of dying with functioning grafts from illnesses such as cancer and cardiovascular conditions. Malignancy has emerged as an important cause of death in transplant recipients and is expected to become the leading cause of death in transplanted patients within the next decade. While it is known that solid organ transplant recipients have a three to five-fold increased risk of developing cancer compared with the general population, the mechanisms that lead to the observed excess risk in transplant recipients are less clear. This review explores the etiology of the increased cancer incidence in solid organ transplant including the effect of immunosuppressants on immunosurveillance and activation of oncogenic viruses, and carcinogenic effects of these medications; the role of chronic stimulation of the immune system on the development of cancer; and the impact of pre-existing cancer risk factors and factors related to end-stage organ disease on the cancer excess incidence in solid organ transplant recipients.

β-HPV Infection Correlates with Early Stages of Carcinogenesis in Skin Tumors and Patient-Derived Xenografts from a Kidney Transplant Recipient Cohort

Many malignancies that occur in high excess in kidney transplant recipients (KTRs) are due to viruses that thrive in the setting of immunosuppression. Keratinocyte carcinoma (KC), the most frequently occurring cancer type in KTR, has been associated with skin infection by human papillomavirus (HPV) from the beta genus. In this report, we extend our previous investigation aimed at identifying the presence of active β-HPV infection in skin tumors from KTRs through detection of viral protein expression. Using a combination of antibodies raised against the E4 and L1 proteins of the β-genotypes, we were able to visualize infection in five tumors [one keratoacanthoma (KA), three actinic keratoses (AKs), and one seborrheic keratoses (SKs)] that were all removed from two patients who had been both transplanted twice, had developed multiple KCs, and presented with a long history of immunosuppression (>30 years). These infected tissues displayed intraepidermal hyperplasia and increased expression of the ΔNp63 protein, which extended into the upper epithelial layers. In addition, using a xenograft model system in nude mice displaying a humanized stromal bed in the site of grafting, we successfully engrafted three AKs, two of which were derived from the aforementioned KTRs and displayed β-HPV infection in the original tumor. Of note, one AK-derived xenograft, along with its ensuing lymph node metastasis, was diagnosed as squamous cell carcinoma (SCC). In the latter, both β-HPV infection and ΔNp63 expression were no longer detectable. Although the overall success rate of engrafting was very low, the results of this study show for the first time that β-HPV⁺ and ΔNp63⁺ intraepidermal hyperplasia can indeed progress to an aggressive SCC able to metastasize. Consistent with a series of reports attributing a causative role of β-HPV at early stages of skin carcinogenesis through ΔNp63 induction and increased keratinocytes stemness, here we provide in vivo evidence that these events are also occurring in the affected skin of KTRs. Due to these β-HPV-driven molecular pathways, the nascent tumor cell is able to acquire a high enough number of carcinogenic insults that its proliferation and survival will eventually become independent of viral gene expression.

Tunneled Indwelling Pleural Catheters for Refractory Pleural Effusions after Solid Organ Transplant. A Case-Control Study

RATIONALE

The use of tunneled indwelling pleural catheters for management of refractory pleural effusions continues to increase. Pleural space infections are among the most common and serious complication of the procedure. The risk may be higher in patients receiving immunosuppressive medications.

OBJECTIVES

The aim of this study was to assess the risk of infections complicating placement of a tunneled indwelling pleural catheter in patients who have received a solid organ transplant.

METHODS

Electronic medical records were retrospectively reviewed to identify patients with prior solid organ transplant who subsequently underwent placement of a tunneled intrapleural catheter. We selected a matched sample of comparison patients without solid organ transplant who underwent the same procedure during the study period. Detailed chart abstraction was performed to compare baseline clinical information with procedure outcomes in both groups.

MEASUREMENTS AND MAIN RESULTS

Nineteen study patients underwent kidney, liver, lung, or heart transplant. Another 55 patients were included in the nontransplant comparison group. Transplant patients were taking a mean of 2.4 (range, 1-4) immunosuppressive medications. In transplant patients, the intrapleural catheter remained in place for a median of 95 days (interquartile range, 58-256 d). Two of the 19 transplant patients (16.9% 90-day Kaplan-Meier estimate) and 4 of the 55 control patients (11.0% weighted 90-day Kaplan-Meier estimate) developed a major infectious complication (not significant). There were no deaths attributed to intrapleural catheter placement in either group.

CONCLUSIONS

In a series of 19 patients with solid organ transplantation taking daily immunosuppressive medications who underwent placement of a tunneled intrapleural catheter, we report an 11% rate of major infectious complications over the lifetime of the catheter in the transplant group with no significant difference in 90-day estimated risk of complication between transplant and nontransplant comparison group.

Gene expression in the twilight of death: The increase of thousands of transcripts has implications to transplantation, cancer, and forensic research

After a vertebrate dies, many of its organ systems, tissues, and cells remain functional while its body no longer works as a whole. We define this state as the "twilight of death" - the transition from a living body to a decomposed corpse. We claim that the study of the twilight of death is important to ethical, legal and medical science. We examined gene expression at the twilight of death in the zebrafish and mouse reaching the conclusion that apparently thousands of transcripts significantly increase in abundance from life to several hours/days postmortem relative to live controls. Transcript dynamics of different genes provided "proof-of-principle" that models accurately predict an individual's elapsed-time-of-death (i.e. postmortem interval). While many transcripts were associated with survival and stress compensation, others were associated with epigenetic factors, developmental control, and cancer. Future studies are needed to determine whether the high incidence of cancer in transplant recipients is due to the postmortem processes in donor organs.

Chemotherapy and Transplantation: The Role of Immunosuppression in Malignancy and a Review of Antineoplastic Agents in Solid Organ Transplant Recipients

It is estimated that solid organ transplant recipients have a two- to fourfold greater overall risk of malignancy than the general population. Some of the most common malignancies after transplant include skin cancers and posttransplant lymphoproliferative disorder. In addition to known risk factors such as environmental exposures, genetics, and infection with oncogenic viruses, immunosuppression plays a large role in the development of cancer through the loss of the immunosurveillance process. The purpose of this article is to explain the role of immunosuppression in cancer and to review the classes of chemotherapeutics. The field of anticancer drugs is continually expanding and developing, with limited data on use in transplant recipients. This article aims to provide information on class review, adverse effects, dose adjustments, and drug interactions that are pertinent to the care of transplant recipients.

A potential role of the unfolded protein response in post-transplant cancer

Cancer is one of the major causes of mortality in organ transplant patients receiving immunosuppressive regimen based on Cyclosporin A (CsA). Organ transplantation and chronic immunosuppression are typically associated with skin cancers (both squamous cell carcinoma and melanoma) and renal cell carcinoma (RCC). Recent studies have shown that in addition to its immunosuppressive effects, accounted for by the inhibition of calcineurin and the modulation of the transcriptional programme of lymphocytes, CsA also directly stimulates the growth and aggressive behaviour of various cancer cells. Using renal carcinogenesis as an example, we discuss the current evidence for a role of cellular proteostasis, i.e. the regulation of the production, maturation and turnover of proteins in eukaryotic cells, in tumorigenesis arising under conditions of chronic immunosuppression. We present the recent studies showing that CsA induces the unfolded protein response (UPR) in normal and transformed kidney cells. We examine how the UPR might be important, considering in particular the genomic analyses showing the existence of a correlation between the levels of expression of the actors of the UPR, the chaperones of the endoplasmic reticulum (ER) and the aggressiveness of renal carcinoma. The UPR may offer a possible explanation for how immunosuppressive regimens based on CsA promote renal carcinogenesis. We discuss the opportunities offered by this biological knowledge in terms of screening, diagnosis and treatment of post-transplant cancers, and propose possible future translational studies examining the role of tumour proteostasis and the UPR in this context.

Metabolic Hallmarks of Tumor and Immune Cells in the Tumor Microenvironment

Cytotoxic T lymphocytes and NK cells play an important role in eliminating malignant tumor cells and the number and activity of tumor-infiltrating T cells represent a good marker for tumor prognosis. Based on these findings, immunotherapy, e.g., checkpoint blockade, has received considerable attention during the last couple of years. However, for the majority of patients, immune control of their tumors is gray theory as malignant cells use effective mechanisms to outsmart the immune system. Increasing evidence suggests that changes in tumor metabolism not only ensure an effective energy supply and generation of building blocks for tumor growth but also contribute to inhibition of the antitumor response. Immunosuppression in the tumor microenvironment is often based on the mutual metabolic requirements of immune cells and tumor cells. Cytotoxic T and NK cell activation leads to an increased demand for glucose and amino acids, a well-known feature shown by tumor cells. These close metabolic interdependencies result in metabolic competition, limiting the proliferation, and effector functions of tumor-specific immune cells. Moreover, not only nutrient restriction but also tumor-driven shifts in metabolite abundance and accumulation of metabolic waste products (e.g., lactate) lead to local immunosuppression, thereby facilitating tumor progression and metastasis. In this review, we describe the metabolic interplay between immune cells and tumor cells and discuss tumor cell metabolism as a target structure for cancer therapy. Metabolic (re)education of tumor cells is not only an approach to kill tumor cells directly but could overcome metabolic immunosuppression in the tumor microenvironment and thereby facilitate immunotherapy.

Imaging spectrum of central nervous system complications of hematopoietic stem cell and solid organ transplantation

Neurologic complications are common after hematopoietic stem cell transplantation (HSCT) and solid organ transplantation (SOT) and affect 30-60% of transplant recipients. The aim of this article is to provide a practical imaging approach based on the timeline and etiology of CNS abnormalities, and neurologic complications related to transplantation of specific organs. The lesions will be classified based upon the interval from HSCT procedure: pre-engraftment period <30 days, early post-engraftment period 30-100 days, late post-engraftment period >100 days, and the interval from SOT procedure: postoperative phase 1-4 weeks, early posttransplant syndromes 1-6 months, late posttransplant syndromes >6 months. Further differentiation will be based on etiology: infections, drug toxicity, metabolic derangements, cerebrovascular complications, and posttransplantation malignancies. In addition, differentiation will be based on complications specific to the type of transplantation: allogeneic and autologous hematopoietic stem cells (HSC), heart, lung, kidney, pancreas, and liver. Thus, in this article we emphasize the strategic role of neuroradiology in the diagnosis and response to treatment by utilizing a methodical approach in the work up of patients with neurologic complications after transplantation.

Prostate Cancer Metastatic to the Renal Allograft: A Case Report

Malignancy is a leading cause of morbidity and mortality in organ transplant recipients who receive immunosuppression. Cancers associated with viruses such as nonmelanotic skin cancer and Kaposi sarcoma occur in allograft recipients at rates that far exceed that in the general population. The increased risk and tumor type may depend not only on degree of immune system modulation but also on the type of organ transplanted. In kidney transplant recipients, the risk of cancers such as prostate and breast does not seem to be increased. However, these cancers tend to be advanced and aggressive. The management of these cancers is similar to the general population with the additional consideration for reduction in immunosuppression and conversion to sirolimus. Given the increased survival of both transplanted organs as well as organ recipients along with the increased number of older recipients, the diagnosis of prostate cancer in the older male organ recipient is increasing. The long-term outcomes using current treatment guidelines for prostate cancer in these individuals are not clear. We report a case of known localized prostate cancer in a renal transplant recipient presenting with metastasis diagnosed as tumor infiltration of the allograft. Our patient, upon initial diagnosis of cancer, opted for radiation with eventual androgen-deprivation therapy. This unusual site of prostate cancer spread heightens the need for awareness among providers as well as the need for further studies of the outcomes in these patients undergoing treatments designed using guidelines developed for those with normally functioning immunity.

Evaluating the mTOR Pathway in Physiological and Pharmacological Settings

Mammalian/mechanistic target of rapamycin (mTOR) is an evolutionarily conserved genuine protein kinase, which phosphorylates serine/threonine in response to growth factors and nutrients. It functions as a catalytic core in two distinct multiprotein complexes: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). mTORC1 promotes cell growth and proliferation by positively regulating translation, transcription, and lipid biosynthesis in response to growth factors and amino acids, whereas it inhibits autophagy, an essential degradation and recycling pathway. mTORC2 regulates cell survival and cytoskeleton organization. Mechanistic insights into the function and regulation of mTOR complexes have been provided in various experimental settings and monitoring mTOR activity has been a most valuable way to judge whether levels of environmental cues such nutrients and growth factors can satisfy cellular needs for cell growth, proliferation, and autophagic response. Here, we describe useful methods to access mTOR activity in different experimental settings.

Dietary interventions that reduce mTOR activity rescue autistic-like behavioral deficits in mice

Enhanced mammalian target of rapamycin (mTOR) signaling in the brain has been implicated in the pathogenesis of autism spectrum disorder (ASD). Inhibition of the mTOR pathway improves behavior and neuropathology in mouse models of ASD containing mTOR-associated single gene mutations. The current study demonstrated that the amino acids histidine, lysine, threonine inhibited mTOR signaling and IgE-mediated mast cell activation, while the amino acids leucine, isoleucine, valine had no effect on mTOR signaling in BMMCs. Based on these results, we designed an mTOR-targeting amino acid diet (Active 1 diet) and assessed the effects of dietary interventions with the amino acid diet or a multi-nutrient supplementation diet (Active 2 diet) on autistic-like behavior and mTOR signaling in food allergic mice and in inbred BTBR T+Itpr3tf/J mice. Cow's milk allergic (CMA) or BTBR male mice were fed a Control, Active 1, or Active 2 diet for 7 consecutive weeks. CMA mice showed reduced social interaction and increased self-grooming behavior. Both diets reversed behavioral impairments and inhibited the mTOR activity in the prefrontal cortex and amygdala of CMA mice. In BTBR mice, only Active 1 diet reduced repetitive self-grooming behavior and attenuated the mTOR activity in the prefrontal and somatosensory cortices. The current results suggest that activated mTOR signaling pathway in the brain may be a convergent pathway in the pathogenesis of ASD bridging genetic background and environmental triggers (food allergy) and that mTOR over-activation could serve as a potential therapeutic target for the treatment of ASD.

Antitumor activity of nivolumab on hemodialysis after renal allograft rejection

BACKGROUND

Nivolumab (Opdivo™) is a novel IgG4 subclass programmed death-1 (PD-1) inhibiting antibody that has demonstrated breakthrough-designation anti-tumor activity. To date, clinical trials of nivolumab and other checkpoint inhibitors have generally excluded patients with solid organ transplantation and patients with concurrent immunosuppression. However, organ transplant recipients are at high-risk of development of malignancy as a result of suppressed immune surveillance of cancer.

CASE PRESENTATION

We illustrate the outcomes of a 63 year-old type I diabetic female patient who developed pulmonary metastatic, BRAF wild-type cutaneous melanoma 10 years after renal transplantation. After downward titration of the patient's immunosuppressive medications and extensive multidisciplinary review, she was treated with nivolumab in the first-line setting. Within 1 week of administration, the patient experienced acute renal allograft rejection, renal failure and concurrent diabetic ketoacidosis due to steroid therapy. Allograft function did not return, but patient made a full clinical recovery after being placed on hemodialysis. Subsequently, the patient had clinical disease progression off therapy and required re-challenge with nivolumab on hemodialysis, resulting in ongoing clinical and radiographic response.

CONCLUSIONS

This case illustrates multiple practical challenges and dangers of administering anti-PD1 immune checkpoint inhibitors to patients with solid-organ transplantation including need for titration of immunosuppressive medications, risks of allograft rejection, and treatment during hemodialysis.

Roles of mTOR complexes in the kidney: implications for renal disease and transplantation

The mTOR pathway has a central role in the regulation of cell metabolism, growth and proliferation. Studies involving selective gene targeting of mTOR complexes (mTORC1 and mTORC2) in renal cell populations and/or pharmacologic mTOR inhibition have revealed important roles of mTOR in podocyte homeostasis and tubular transport. Important advances have also been made in understanding the role of mTOR in renal injury, polycystic kidney disease and glomerular diseases, including diabetic nephropathy. Novel insights into the roles of mTORC1 and mTORC2 in the regulation of immune cell homeostasis and function are helping to improve understanding of the complex effects of mTOR targeting on immune responses, including those that impact both de novo renal disease and renal allograft outcomes. Extensive experience in clinical renal transplantation has resulted in successful conversion of patients from calcineurin inhibitors to mTOR inhibitors at various times post-transplantation, with excellent long-term graft function. Widespread use of this practice has, however, been limited owing to mTOR-inhibitor- related toxicities. Unique attributes of mTOR inhibitors include reduced rates of squamous cell carcinoma and cytomegalovirus infection compared to other regimens. As understanding of the mechanisms by which mTORC1 and mTORC2 drive the pathogenesis of renal disease progresses, clinical studies of mTOR pathway targeting will enable testing of evolving hypotheses.

Tumor-Infiltrating Lymphocytes: A Promising Biomarker in Breast Cancer

There is clear evidence that the immune system plays an essential role in tumor defense. By determining tumor-infiltrating lymphocytes (TILs), the individual immunological response becomes more apparent and measurable. In breast cancer, high levels of TILs are associated with a more favorable clinical course. In this review, we describe how TILs are determined with emphasis on daily routine diagnostics. We further discuss their impact as a prognostic and predictive biomarker in the neoadjuvant and adjuvant therapy setting as well as in residual disease. We also discuss their potential future implications on further stratifying prognostic subgroups of breast cancer, thereby possibly influencing future therapy considerations.