Tumorigenic role of tacrolimus through mTORC1/C2 activation in post-transplant renal cell carcinomas.

BACKGROUND: Kidney transplant recipients (KTRs) face an increased risk of renal cell carcinoma (RCC), in which the immunosuppressive regimen plays an important role. This study aimed to identify intracellular signalling alterations associated with post-transplant (post-tx) tumour formation. METHODS: Expression of mTOR-related proteins were analysed in kidneys obtained from end-stage renal disease (ESRD) patients and RCCs developed in KTRs or non-transplant patients. The effects of tacrolimus (TAC) and rapamycin (RAPA) on mTOR activity, proliferation, and tumour growth were investigated through different in vitro and in vivo experiments. RESULTS: Elevated mTORC1/C2 activity was observed in post-tx RCCs and in kidneys of TAC-treated ESRD patients. In vitro experiments demonstrated that TAC increases mTOR activity in a normal tubular epithelial cell line and in the investigated RCC cell lines, moreover, promotes the proliferation of some RCC cell line. In vivo, TAC elevated mTORC1/C2 activity in ischaemic kidneys of mice and enhanced tumour growth in xenograft model. CONCLUSIONS: We observed significantly increased mTOR activity in ischaemic kidneys and post-tx RCCs, which highlights involvement of mTOR pathway both in the healing or fibrotic processes of kidney and in tumorigenesis. TAC-treatment further augmented the already elevated mTOR activity of injured kidney, potentially contributing to tumorigenesis during immunosuppression.

Oncological Screening of Kidney Tumors After Renal Transplantation.

BACKGROUND: Among renal transplant recipients, renal cell carcinoma in the native kidneys represents the most common solid tumor. At the Department of Surgery, Transplantation and Gastroenterology of Semmelweis University annual control abdominal ultrasound examination is recommended for transplant patients. Our goal was to evaluate the effectiveness of the ultrasound screening program at our institute and to learn about the characteristics of shrunken kidney tumors. METHODS: Retrospectively, we processed the results of abdominal and pelvic ultrasound examinations of 1687 kidney transplant patients, which were performed at our institute between January 1, 2012 and December 31, 2016. RESULTS: A total of 26 tumors were detected during the abovementioned period of time, of which 18 were renal cancers. Renal cancer was significantly (P = 0.029) more common in men. Seventeen renal cancers were classified as stage I and one as stage IV disease. The mean time of dialysis was 37.73 ± 24.37 months. The mean time between kidney transplantation and tumor recognition was 7.9 ± 6.29 years. The 5-year survival was 66%; however, it should be noted that only 1 patient lost his life due to his tumor disease. The mean time between the last 2 ultrasound examinations was 27.8 ± 23.89 months. Only 57% of tumors were detected by screening. No significant differences in tumor size, stage, and survival could be detected between screened and nonscreened renal cancer patients. CONCLUSIONS: Ultrasound examination at least every 2 years is an effective tool for the early detection of renal cell carcinoma of the shrunken kidneys.

Metabolic Adaptation as Potential Target in Papillary Renal Cell Carcinomas Based on Their In Situ Metabolic Characteristics.

Metabolic characteristics of kidney cancers have mainly been obtained from the most frequent clear cell renal cell carcinoma (CCRCC) studies. Moreover, the bioenergetic perturbances that affect metabolic adaptation possibilities of papillary renal cell carcinoma (PRCC) have not yet been detailed. Therefore, our study aimed to analyze the in situ metabolic features of PRCC vs. CCRCC tissues and compared the metabolic characteristics of PRCC, CCRCC, and normal tubular epithelial cell lines. The protein and mRNA expressions of the molecular elements in mammalian target of rapamycin (mTOR) and additional metabolic pathways were analyzed in human PRCC cases compared to CCRCC. The metabolic protein expression pattern, metabolite content, mTOR, and metabolic inhibitor sensitivity of renal carcinoma cell lines were also studied and compared with tubular epithelial cells, as "normal" control. We observed higher protein expressions of the "alternative bioenergetic pathway" elements, in correlation with the possible higher glutamine and acetate consumption in PRCC cells instead of higher glycolytic and mTOR activity in CCRCCs. Increased expression of certain metabolic pathway markers correlates with the detected differences in metabolite ratios, as well. The lower lactate/pyruvate, lactate/malate, and higher pyruvate/citrate intracellular metabolite ratios in PRCC compared to CCRCC cell lines suggest that ACHN (PRCC) have lower Warburg glycolytic capacity, less pronounced pyruvate to lactate producing activity and shifted OXPHOS phenotype. However, both studied renal carcinoma cell lines showed higher mTOR activity than tubular epithelial cells cultured in vitro, the metabolite ratio, the enzyme expression profiles, and the higher mitochondrial content also suggest increased importance of mitochondrial functions, including mitochondrial OXPHOS in PRCCs. Additionally, PRCC cells showed significant mTOR inhibitor sensitivity and the used metabolic inhibitors increased the effect of rapamycin in combined treatments. Our study revealed in situ metabolic differences in mTOR and metabolic protein expression patterns of human PRCC and CCRCC tissues as well as in cell lines. These underline the importance in the development of specific new treatment strategies, new mTOR inhibitors, and other anti-metabolic drug combinations in PRCC therapy.

Oncological Screening of Kidney Transplant Patients: The Role of Ultrasound Examination.

INTRODUCTION: Immunosuppressive therapy used after organ transplantation represents a considerable oncological risk. Abdominal ultrasound examinations play an essential role in the oncological screening of organ transplant patients. Our aim was to study the effectiveness of the ultrasound screening protocol currently used in our clinic. METHODS: Reports of screening abdominal ultrasound examinations of kidney transplant recipients were processed at the Department of Transplantation and Surgery of Semmelweis University from January 2012 to December 2015. RESULTS: In 1478 studies, 14 patients were diagnosed with a malignant tumor, 11 of which were formed in the native shrunken kidney. The mean age for tumor diagnosis was 55.6 ± 12.6 years, and 80% of the patients diagnosed with tumor were male. On average, 7.5 ± 4.6 years passed between the transplantation and recognition of the tumor. All of the kidney tumors were diagnosed at an early stage: histologic examination of removed kidneys showed 73% pT1a- and 17% pT1b-stage tumors. CONCLUSION: In our study, early stage shrunken kidney cancers were outstandingly the most common post-transplant malignancies found by ultrasound screening. Annual ultrasound examinations as part of our current screening protocol allowed the detection of tumors at an early stage in kidney transplant recipients.

Diagnosis and Management of a De Novo Urothelial Carcinoma in a Kidney Allograft: A Case Report.

INTRODUCTION: Following renal transplantation, the incidence of malignancies is 3-5 times higher than that of healthy individuals. Among other type of cancers, the risk of urological tumors is also elevated. However, only a few cases of de novo transitional cell carcinomas occurring in renal allografts have been reported. CASE REPORT: A 63-year-old tertiary transplanted male patient was urgently hospitalized for a painless macroscopic hematuria. Ultrasonography revealed pyelectasis and a hematoma in the renal pelvis. A percutaneous nephrostomy tube was inserted. An anterograde pyelography was performed later, where a filling defect was still observable in the location of the previously reported hypoechoic mass. Contrast-enhanced ultrasonography showed enhancement of the lesion. An ultrasound-guided percutaneous biopsy was performed. The histologic evaluation revealed a high-grade transitional cell carcinoma. A whole-body staging computed tomography scan did not show signs of metastatic disease. The renal allograft was surgically removed. No disease progression was observed during the 21-month follow-up period. CONCLUSIONS: Painless hematuria and asymptomatic hydronephrosis occurring after kidney transplantation should raise the possibility of urothelial carcinoma in the kidney graft. Contrast-enhanced ultrasound should be considered as a first-line diagnostic modality because it is easily accessible and does not raise concerns about nephrotoxicity or radiation burden.

The Effects of Different mTOR Inhibitors in EGFR Inhibitor Resistant Colon Carcinoma Cells.

Several monoclonal antibodies and inhibitors targeting signalling pathways are being used in personalised medicine. Anti-EGFR antibodies seem to be effective, however, therapy resistance often occurs in colon carcinoma cases. mTOR inhibitors (mTORIs) could have a potential role in the breakthrough of therapy resistance. The mTOR activity related protein expression patterns and the in vitro effects of EGFR inhibitors (EGFRIs), mTORIs and their combinations were studied in different colon carcinoma cell lines (with different genetic backgrounds). Alamar Blue test and flow cytometry were used to analyse the in vitro proliferation and apoptotic effects of cetuximab, gefitinib, cisplatin, rapamycin, PP242 and NVP-BEZ235. The expressions of mTOR activity related proteins (p-70S6K, p-S6, Rictor, p-mTOR, Raptor) were studied by Western blot, immunocytochemistry and Duolink staining. The EGFRI resistance of the studied colon carcinoma cell lines related to their known mutations were confirmed, neither gefitinib nor cetuximab inhibited the proliferation or induced apoptosis in vitro. Individual differences in Rictor and Raptor expressions were detected by Western blot and immunocytochemistry beside elevated mTOR activity of these different colon carcinoma cell lines. These expression patterns correlated to the mTORIs sensitivity differences, moreover, mTORIs could enhance the effects of EGFRIs and other in vitro treatments. Our results suggest that mTORI combinations could be helpful in both EGFRI and platinum-based therapy of colon carcinomas. Moreover, we suggest determining both mTOR complex activity and mutations in Akt/mTOR signalling pathways for selecting the appropriate mTORIs and patients in potential future combination treatments.

[Liver transplantation in the treatment of hepatic tumors]. / A májátültetés szerepe a májdaganatok kezelésében.

The indications for liver transplantation have become generally accepted over the last decades. However, in the last ten years, this indication area changes, it seems to be enlarged. Increasingly, previously classified as contraindications have become indications like cholangiocarcinoma or colorectal cancer liver metastases in selected cases. We have reviewed the old and new oncologic indications, whose survival rates do not differ from liver transplants due to other indications.

[Surgical treatment of secondary liver malignancies]. / A máj másodlagos rosszindulatú daganatainak sebészi kezelése.

Surgical treatment of liver metastases, under certain conditions, can be a step of a multidisciplinary treatment strategy for advanced malignant disease. Nevertheless, it is not the same if metachronous or synchronous metastases are planned to be treated. Indications for surgery are the most clearly defined and accepted in cases of colorectal and neuroendocrine liver metastases. At the same time, the steps of the traditional oncotherapy has changed in the management of synchronous colorectal metastases: the novel concept of the treatment strategy is removing the liver metastases before the colorectal primary. The role of surgery is less clear and defined in the management of metastases from other, non-colorectal and non-neuroendocrine primaries. The main purpose is to evaluate which kind of criteria should be fulfilled to indicate the resection of liver metastases, which are the conditions that, when present, may provide a benefit to a patient from surgery, improving survival. These criteria have not been clarified precisely yet; randomized prospective trials are needed. Consensus recommendations in such cases could be determined based on the results of the mentioned trials.

mTOR activity and its prognostic significance in human colorectal carcinoma depending on C1 and C2 complex-related protein expression.

AIMS: Tumour heterogeneity and altered activation of signalling pathways play important roles in therapy resistance. The PI3K/Akt/mTOR signalling network is a well-known regulator of several functions that contribute to tumour growth. mTOR exists in two functionally different multiprotein complexes. We aimed to determine mTOR activity-related proteins in clinically followed, conventionally treated colon carcinomas and to analyse the correlation between clinical data and mTORC1 and mTORC2 activity. METHODS: Immunohistochemistry was performed with different antibodies on tissue microarray blocks from 103 patients with human colorectal adenocarcinoma. mTORC1- and mTORC2-related activity were scored on different stainings including analysis of the expression of Raptor and Rictor-specific elements of mTORC1 and C2 complexes. The staining scores and clinical/survival data were compared and analysed. RESULTS: Detailed characterisation showed stage and grade independent high mTOR activity in 74% of cases. High mTOR activity was present in mTORC1 and/or mTORC2 complexes; >60% of cases had mTORC2-related high mTOR activity. Based on our analysis, high mTOR activity and Rictor overexpression could be markers of a bad prognosis. Combined phosphoprotein and Rictor/Raptor expression evaluation revealed even stronger statistical correlation with prognosis. CONCLUSIONS: The presented staining panel could be appropriate and highly recommended for the accurate specification of mTORC1 and C2 activity of tumour tissues. This could help in the selection of mTOR inhibitors and can provide information about prognosis, which may guide decisions about the intensity of therapy.

Rapamycin can restore the negative regulatory function of transforming growth factor beta 1 in high grade lymphomas.

TGF-ß1 (transforming growth factor beta 1) is a negative regulator of lymphocytes, inhibiting proliferation and switching on the apoptotic program in normal lymphoid cells. Lymphoma cells often lose their sensitivity to proapoptotic/anti-proliferative regulators such as TGF-ß1. Rapamycin can influence both mTOR (mammalian target of rapamycin) and TGF-ß signaling, and through these pathways it is able to enhance TGF-ß induced anti-proliferative and apoptotic responses. In the present work we investigated the effect of rapamycin and TGF-ß1 combination on cell growth and on TGF-ß and mTOR signalling events in lymphoma cells. Rapamycin, an inhibitor of mTORC1 (mTOR complex 1) did not elicit apoptosis in lymphoma cells; however, the combination of rapamycin with exogenous TGF-ß1 induced apoptosis and restored TGF-ß1 dependent apoptotic machinery in several lymphoma cell lines with reduced TGF-ß sensitivity in vitro. In parallel, the phosphorylation of p70 ribosomal S6 kinase (p70S6K) and ribosomal S6 protein, targets of mTORC1, was completely eliminated. Knockdown of Smad signalling by Smad4 siRNA had no influence on apoptosis induced by the rapamycin+TGF-ß1, suggesting that this effect is independent of Smad signalling. However, apoptosis induction was dependent on early protein phosphatase 2A (PP2A) activity, and in part on caspases. Rapamycin+TGF-ß1 induced apoptosis was not completely eliminated by a caspase inhibitor. These results suggest that high mTOR activity contributes to TGF-ß resistance and lowering mTORC1 kinase activity may provide a tool in high grade B-cell lymphoma therapy by restoring the sensitivity to normally available regulators such as TGF-ß1.

MARS therapy, the bridging to liver retransplantation - Three cases from the Hungarian liver transplant program.

Besides orthotopic liver transplantation (OLT) there is no long-term and effective replacement therapy for severe liver failure. Artificial extracorporeal liver supply devices are able to reduce blood toxin levels, but do not replace any synthetic function of the liver. Molecular adsorbent recirculating system (MARS) is one of the methods that can be used to treat fulminant acute liver failure (ALF) or acute on chronic liver failure (AoCLF). The primary non-function (PNF) of the newly transplanted liver manifests in the clinical settings exactly like acute liver failure. MARS treatment can reduce the severity of complications by eliminating blood toxins, so that it can help hepatic encephalopathy (HE), hepatorenal syndrome (HRS), and the high rate mortality of cerebral herniation. This might serve as a bridging therapy before orthotopic liver retransplantation (reOLT). Three patients after a first liver transplantation became candidate for urgent MARS treatment as a bridging solution prior to reOLT in our center. Authors report these three cases, fo-cusing on indications, MARS sessions, clinical courses, and final outcomes.

Detection and management of renal cell carcinoma in the renal allograft.

PURPOSE: Tumours of the transplanted kidney represent a rare form of post-transplantation malignancies. An important aspect of the treatment option is whether the transplanted kidney can be saved or not. Aim of our study was the analysis of our allograft tumours. METHODS: In the Budapest Centre, 3,530 kidney transplantations were performed between 1973 and 2012. Retrospective analysis of 9 patients who developed renal cell carcinoma (RCC) in the transplanted kidney was done. RESULTS: Mean age of recipients was 45.3 ± 13.4 years at the time of transplantation and 57.0 ± 11.6 years at the time of tumour detection. Mean age of their donors was 43.5 ± 11.5 years. Mean time from transplantation to tumour diagnosis was 134.6 ± 40.8 months. Seven RCC were stage pT1a, 1 was stage pT1b and 1 was pT3a. Eight patients had stage I. (pT1a-b, N0, M0) and 1 patient had stage IV. (pT3a, N1, M1) disease. Histological types were clear cell (n = 6), papillary (n = 2) and sarcomatoid (n = 1) carcinomas. The tumour growth rate of RCC was 16.7 ± 13.5 mm/year. In 4 cases, transplant nephrectomy was performed; 5 cases had percutaneous radiofrequency ablation (RFA). Ablative therapy had no influence on renal graft function. Six patients (including 5 patients who were treated with RFA) are still alive and tumour-free; 3 patients died. CONCLUSIONS: According to our observation, we can state that RCC of the kidney allograft diagnosed at an early stage can be successfully treated with RFA instead of graft removal. A longer follow-up is needed to assess the effectivity of the RFA treatment in these cases.

Role of organ transplantation in the treatment of malignancies: hepatocellular carcinoma as the most common tumour treated with transplantation.

There are only few malignant tumours where organ transplantation is the treatment of choice. Transplantation can be considered individually in certain lung carcinomas, unresectable heart tumours, cholangiocellular carcinoma and Klatskin tumour. It is acceptable in unresectable chemosensitive hepatoblastoma, epitheloid haemangioendothelioma, liver metastasis of neuroendocrine tumours and as the most common indication, the early hepatocellular carcinoma (HCC) in cirrhotic liver. Results of liver transplantation (LT) for HCC according to Milan criteria as a "gold standard" are excellent. Time of LT has a great influence on the results. While patients are on waiting list, locoregional therapies may help prevent tumour progress. Living donor LT is an acceptable treatment of HCC. The greatest experience with this procedure is in Asia. Despite the favourable results, LT as the treatment of HCC is debated and raises several questions: regarding indication and expectable outcome. Milan criteria seem to answer this questions although they are too strict. The number and size of HCC foci per se is not sufficient predictor of eligibility to transplantation and for prognosis. Majority of the prognostic factors can be evaluated only after transplantation with pathological examination of HCC. Aim of the present research is to find prognostic factors that are characteristic of biological behaviour of HCC, which can be detected before LT in order to select patients who have the greatest benefit from LT. Re-definition of eligibility criteria is an actual question; an international consensus based on additional prospective studies is required for the "new" recommendation.

Molecular profiling of parathyroid hyperplasia, adenoma and carcinoma.

The objective of the study was to examine proliferation and apoptosis associated gene expression in the whole sequence parathyroid lesions to reveal specific features of carcinoma. This study was based on surgically removed parathyroid tissues, gene expression analysis was performed both at gene and protein level. First, mRNA isolation was performed from deep-frozen tissue samples, and further apoptosis pathway-specific cDNA macroarray analysis was carried out. The results were validated with real-time PCR. Subsequently, protein expression was analyzed with immunhistochemistry on Tissue Micro Array multi-blocks derived from several paraffin-embedded samples. cDNA macroarrays revealed elevated expression of both pro-apoptotic (FAS receptor, TRAIL ligand, CASPASE8, and -4) and anti-apoptotic (cIAP1, APOLLON) genes in benign proliferative lesions compared to that in normal gland. TMA studies showed overexpression of KI67, P53, SURVIVIN and APOLLON protein and failure of expression of P27, BCL2, BAX, CHROMOGRANIN-A, SYNAPTOPHYSIN, CYCLIND1, FLIP, TRAIL, CK8, CK18, CK19 in parathyroid carcinoma was detected. These alterations in gene expression of the investigated products could be used in differentiation between beningn and malignant proliferative processes of the parathyroid gland. Authors conclude that a series of alterations in gene expression such as overexpression of APOLLON, P53, KI67 and suppression of P27, BCL2, BAX lead to uncontrolled cell proliferation, but still not leading to increased apoptotic activity in parathyroid carcinoma.

Lymphoproliferative disorders after solid organ transplantation-classification, incidence, risk factors, early detection and treatment options.

Posttransplant lymphoproliferative disorder (PTLD) is a heterogeneous disease group of benign and malignant entities. The new World Health Organisation classification introduced in 2008 distinguishes early lesions, polymorphic, monomorphic and classical Hodgkin lymphoma-type PTLD. Based on the time of appearance, early and late forms can be identified.PTLDs are the second most frequent posttransplantation tumors in adulthood, and the most frequent ones in childhood. The incidence varies with the transplanted organ-from 1%-2% following kidney transplantation to as high as 10% following thoracic organ transplantation-due to different intensities in immunosuppression. Immunocompromised state and Epstein-Barr virus (EBV) infection are the two major risk factors.In Europe and the US approximately 85% of PTLDs are of B-cell origin, and the majority are EBV-associated. Symptoms are often unspecific; extranodal, organ manifestations and central nervous system involvement is common. Early lesions respond well to a decrease in immunosuppression. Malignant entities are treated with rituximab, chemotherapy, radiotherapy and surgical therapy. Adoptive T-cell transfer represents a promising therapeutic approach. The prognosis is favorable in early PTLD, and poor in late PTLD. Five-year survival is 30% for high-grade lymphomas. The prognosis of EBV-negative lymphomas is worse.Lowering the risk of PTLD may be achieved by low dose maintenance immunosuppression, immunosuppressive drugs inhibiting cell proliferation, and special immunotherapy (e.g. interleukin-2 inhibitors). Early detection is especially important for high risk-e.g. EBV-negative-patients, where the appearance of EBV-DNA and the increase in its titer may help.

[Post-transplantation malignant tumors and the challenges of immunosuppressive therapy in transplanted patients developing lymphoma. Mycophenolic acid as a possibility]. / A szervátültetést követô rosszindulatú daganatok problémája, különös tekintettel a lymphomában szenvedô, transzplantált betegeknél választandó immunszuppresszív kezelésre. A mycophenolsav, mint lehetôség.

The increasing frequency of malignant tumors developing during chronic immunosuppression is an important determinant of the long-term survival of organ transplanted patients. This problem can be solved only if we are aware of the special characteristics concerning our patients. The incidence and frequency of tumors occurring in kidney transplant recipients differ from those of the Hungarian population. The increased tumor risk resulting from chronic renal failure, increasing age of prospective kidney recipients and, in addition, the increasing frequency of tumors diagnosed in the early post-transplantation period emphasize the importance of regular oncological screening of patients on the waiting list. Early diagnosis and treatment of tumors and precancerous conditions are equally important in transplanted patients as well, and the tumor risk could be decreased by applying low dose immunosuppression and the preferential usage of immunosuppressive drugs with an oncologically favorable effect. The prognosis of post-transplantation tumors is poor, as they respond poorly to therapy. Lymphomas are of great importance because of their frequency. Different immunosuppressive regimens represent varying degrees of risk in lymphoma development. This risk is lower in the case of mycophenolic acid. The composition of immunosuppression is a major factor in treatment; an oncologically ideal compound would prevent organ rejection and, at the same time, would not counteract oncological therapy. We have shown that mycophenolic acid inhibits the proliferation of human B-cell non-Hodgkin lymphomas and induces apoptosis by activating the intrinsic pathway, both in vitro and in vivo. The favorable properties of mycophenolic acid suggest that it can provide the necessary immunoprotection for the transplanted organ and, given its anti-lymphoma effects, it may also prove useful in the therapy of lymphoma patients. It may also be helpful in the treatment of "traditional" lymphomas of the non-transplanted population, where the major cause of therapeutical failure is the development of apoptosis resistance. Mycophenolic acid, combined with other chemotherapeutical drugs, may enhance apoptosis in lymphoma cells. Our promising experimental results provide a basis for further, clinical studies.

[Malignant tumors following renal transplantation]. / A veseátültetést követoen kialakuló rosszindulatú daganatok.

Patient survival time following renal and other solid organ transplantation has been increasing recently, in part due to modern immunosuppressive regimens. However, the probability of malignant tumor formation is also increasing proportionally to survival time, as a side effect of long-term immunosuppression. The primary factor of increased tumor risk is the deficient antitumoral and antiviral function of the immune system. The frequency of posttransplantation tumors is 2 to 4-fold compared to the non-transplanted population, and the distribution of tumor types is also different. The most frequent tumor types--skin cancer, lymphoma, Kaposi's sarcoma, oral cancer, anogenital tumors, etc.--are often associated with oncogenic viruses. Treatment options and the prognosis of posttransplant tumors are worse than in the normal population. The increasing frequency of posttransplantation tumors is an important factor determining the long-term fate of transplant patients. The reduction of carcinogenic agents, the early diagnosis and treatment of tumors and precancerous conditions, low dose immunosuppression and the usage of immunosuppressive agents with an oncologically favorable, anti-proliferative effect will help reduce the risk of posttransplant tumor formation.

Malignancies after renal transplantation during 33 years at a single center.

This study provides an analysis of incidence and characteristics of malignant tumors of 2535 patients who underwent renal transplantation between 1973 and 2007 at the Transplantation Center in Budapest. One hundred ninety-three malignant diseases were found in 188 patients (7.6%). The incidence of thyroid-, renal- hepatic-, skin- and gastric cancers as well as of Kaposi sarcoma and lymphomas increased in our transplant patient cohort compared to the figures of the general population based on the data of our Cancer Registry. On the other hand, colorectal-, oralprostate and lung cancers were underrepresented in our patient cohort. The mean time of diagnosis of malignancies following kidney transplantation was 58.5+/-44.8 months. One fifth of the tumors were detected within the first year. Patients with malignancies were distributed into four groups based on the immunosuppressive regimen: group I (8.5%), azathioprine + prednisone; group II (59.0%), cyclosporine + prednisone; group III (26.6%), cyclosporine + mycophenolate mofetil + prednisone; group IV (5.9%), tacrolimus + mycophenolate mofetil + prednisone. The mean age of patients was 47.3, 53.5, 55.5 and 58.1 years in group I, II, III and IV, respectively. Oncologic and immunosuppressive therapy was decided individually. Immunosuppression was switched to rapamycin-containing regimens in 63 cases. We lost 92 patients (48.9%) with a mean survival time of 25.8+/-39.4 months. Cumulative 1- and 5-year survivals were 69.5% and 52%, respectively. The increasing number of cancers seen early after transplantation and the increased risk of developing a cancer due to the older age of recipients draw attention to the importance of regular oncologic screening in patients on the waiting list and after transplantation.

Antiproliferative and apoptotic effects of mycophenolic acid in human B-cell non-Hodgkin lymphomas.

Mycophenolic acid (MPA)/mycophenolate mofetil (MMF), a powerful immunosuppressive agent was tested on human B-lymphoma cells (Epstein-Barr virus +/-) in vitro and in SCID mouse xenograft model. Proliferation, apoptotic activity and tumor volume were evaluated. MPA inhibited lymphoma cell proliferation and induced apoptosis (50-60% at 72 h). In vivo, oral administration significantly inhibited subcutaneous tumor growth. Immunohistochemistry showed significantly decreased proliferation rate and higher apoptotic activity in tumors treated with MMF. Xenografted lymphoma cells remained sensitive to MPA. Our results suggest that MPA may be recommended as an additional component of lymphoma chemotherapeutical regimens, with special considerations to post-transplant lymphomas.