Gyula Végső

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.

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.

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.

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

TGF-β1 (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-β1. Rapamycin can influence both mTOR (mammalian target of rapamycin) and TGF-β signaling, and through these pathways it is able to enhance TGF-β induced anti-proliferative and apoptotic responses. In the present work we investigated the effect of rapamycin and TGF-β1 combination on cell growth and on TGF-β 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-β1 induced apoptosis and restored TGF-β1 dependent apoptotic machinery in several lymphoma cell lines with reduced TGF-β 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-β1, 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-β1 induced apoptosis was not completely eliminated by a caspase inhibitor. These results suggest that high mTOR activity contributes to TGF-β 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-β1.

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.

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.

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.

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.