A Gene Expression Signature to Select Hepatocellular Carcinoma Patients for Liver Transplantation.

OBJECTIVE: To propose a new decision algorithm combining biomarkers measured in a tumor biopsy with clinical variables, to predict recurrence after liver transplantation (LT). BACKGROUND: Liver cancer is one of the most frequent causes of cancer-related mortality. LT is the best treatment for hepatocellular carcinoma (HCC) patients but the scarcity of organs makes patient selection a critical step. In addition, clinical criteria widely applied in patient eligibility decisions miss potentially curable patients while selecting patients that relapse after transplantation. METHODS: A literature systematic review singled out candidate biomarkers whose RNA levels were assessed by quantitative PCR in tumor tissue from 138 HCC patients submitted to LT (>5 years follow up, 32% beyond Milan criteria). The resulting 4 gene signature was combined with clinical variables to develop a decision algorithm using machine learning approaches. The method was named HepatoPredict. RESULTS: HepatoPredict identifies 99% disease-free patients (>5 year) from a retrospective cohort, including many outside clinical criteria (16%-24%), thus reducing the false negative rate. This increased sensitivity is accompanied by an increased positive predictive value (88.5%-94.4%) without any loss of long-term overall survival or recurrence rates for patients deemed eligible by HepatoPredict; those deemed ineligible display marked reduction of survival and increased recurrence in the short and long term. CONCLUSIONS: HepatoPredict outperforms conventional clinical-pathologic selection criteria (Milan, UCSF), providing superior prognostic information. Accurately identifying which patients most likely benefit from LT enables an objective stratification of waiting lists and information-based allocation of optimal versus suboptimal organs.

Patient-Derived Explants of Colorectal Cancer: Histopathological and Molecular Analysis of Long-Term Cultures.

Colorectal cancer (CRC) is one of the most common cancers worldwide. Although short-term cultures of tumour sections and xenotransplants have been used to determine drug efficacy, the results frequently fail to confer clinically useful information. Biomarker discovery has changed the paradigm for advanced CRC, though the presence of a biomarker does not necessarily translate into therapeutic success. To improve clinical outcomes, translational models predictive of drug response are needed. We describe a simple method for the fast establishment of CRC patient-derived explant (CRC-PDE) cultures from different carcinogenesis pathways, employing agitation-based platforms. A total of 26 CRC-PDE were established and a subset was evaluated for viability (n = 23), morphology and genetic key alterations (n = 21). CRC-PDE retained partial tumor glandular architecture and microenvironment features were partially lost over 4 weeks of culture. Key proteins (p53 and Mismatch repair) and oncogenic driver mutations of the original tumours were sustained throughout the culture. Drug challenge (n = 5) revealed differential drug response from distinct CRC-PDE cases. These findings suggest an adequate representation of the original tumour and highlight the importance of detailed model characterisation. The preservation of key aspects of the CRC microenvironment and genetics supports CRC-PDE potential applicability in pre- and co-clinical settings, as long as temporal dynamics are considered.

Centrosome amplification arises before neoplasia and increases upon p53 loss in tumorigenesis.

Centrosome abnormalities are a typical hallmark of human cancers. However, the origin and dynamics of such abnormalities in human cancer are not known. In this study, we examined centrosomes in Barrett's esophagus tumorigenesis, a well-characterized multistep pathway of progression, from the premalignant condition to the metastatic disease. This human cancer model allows the study of sequential steps of progression within the same patient and has representative cell lines from all stages of disease. Remarkably, centrosome amplification was detected as early as the premalignant condition and was significantly expanded in dysplasia. It was then present throughout malignant transformation both in adenocarcinoma and metastasis. The early expansion of centrosome amplification correlated with and was dependent on loss of function of the tumor suppressor p53 both through loss of wild-type expression and hotspot mutations. Our work shows that centrosome amplification in human tumorigenesis can occur before transformation, being repressed by p53. These findings suggest centrosome amplification in humans can contribute to tumor initiation and progression.

Over-elongation of centrioles in cancer promotes centriole amplification and chromosome missegregation.

Centrosomes are the major microtubule organising centres of animal cells. Deregulation in their number occurs in cancer and was shown to trigger tumorigenesis in mice. However, the incidence, consequence and origins of this abnormality are poorly understood. Here, we screened the NCI-60 panel of human cancer cell lines to systematically analyse centriole number and structure. Our screen shows that centriole amplification is widespread in cancer cell lines and highly prevalent in aggressive breast carcinomas. Moreover, we identify another recurrent feature of cancer cells: centriole size deregulation. Further experiments demonstrate that severe centriole over-elongation can promote amplification through both centriole fragmentation and ectopic procentriole formation. Furthermore, we show that overly long centrioles form over-active centrosomes that nucleate more microtubules, a known cause of invasiveness, and perturb chromosome segregation. Our screen establishes centriole amplification and size deregulation as recurrent features of cancer cells and identifies novel causes and consequences of those abnormalities.

Lymph Node Metastases in Papillary and Medullary Thyroid Carcinoma Are Independent of Intratumoral Lymphatic Vessel Density.

BACKGROUND: Blood and lymph vessel invasion are well-recognized markers of tumor aggressiveness, as these are the routes that lead to metastases. Thyroid tumors, depending on the histological variant, tend to have distinctive biological behaviors and use different vascular routes to metastasize, yet the mechanisms underlying the metastatic process are still poorly understood. OBJECTIVES: The aim of this study was to assess how the lymph vessel density (LVD) in different histological types of thyroid tumors, and in their surrounding tissue, correlate with the presence of lymph node metastases (LNM) and tumor pathological features. METHODS: Lymph vessels of papillary thyroid carcinomas (PTC), of the classical (CVPTC, n = 50) and follicular variants (FVPTC, n = 18), and medullary thyroid carcinomas (MTC, n = 34) were immunohistochemically stained against antigen D2-40. The stained area was quantified using a computerized morphometric analysis tool and correlated with the tumor pathological characteristics. RESULTS: LVD within all analyzed thyroid tumor subtypes was significantly lower than in the surrounding thyroid tissues (p < 0.001). Despite intratumoral LVD being significantly higher in CVPTC than in FVPTC, and peritumoral LVD being significantly higher in MTC than in PTC (p < 0.05), no correlations were found between LVD (either intratumoral or peritumoral) and the presence of lymph node metastasis. CONCLUSIONS: As no LVD differences were found amongst thyroid tumors with or without LNM, dissemination is more likely to depend on the tumor ability to invade the abundant lymph vessel network of the surrounding thyroid tissue than on the ability of the tumor to promote de novo lymphangiogenesis.

Expression and function of the chemokine receptor CCR7 in thyroid carcinomas.

The chemokine receptor CCR7 plays a critical role in lymphocyte and dendritic cell trafficking into and within lymph nodes, the preferential metastatic site for papillary (PTC) and medullary (MTC) thyroid carcinomas. In order to determine a possible role for CCR7 in mediating the metastatic behaviour of thyroid carcinomas, we analysed its expression in normal and tumoral thyroid tissues of different histotypes and studied the in vitro effects of its activation by the CCR7 ligand, CCL21. Using real-time quantitative-PCR, we observed that CCR7 expression was higher in PTCs and MTCs than in follicular and poorly differentiated thyroid carcinomas. CCR7 expression was ninefold higher in classic compared with follicular variants of PTCs, and its expression in MTCs was significantly correlated with lymph node metastases. Immunohistochemical staining for CCR7 showed protein expression in neoplastic thyroid cells, with higher intensity in PTCs, MTCs and their lymph node metastases (LNMs). We further showed that CCL21 stimulation of a CCR7-expressing thyroid tumour cell line (TPC-1) promotes cell proliferation and migration, and the chemotactic effect of CCL21 in these cells involves actin polymerization, increased beta1-integrin expression and increased matrix metalloproteinase secretion. Taken together, our results demonstrate that CCR7 activation on thyroid carcinoma cells by CCL21 - a chemokine abundantly expressed in lymph nodes - favours tissue invasion and cell proliferation, and therefore may promote thyroid carcinoma growth and LNM.

CYR61 and TAZ Upregulation and Focal Epithelial to Mesenchymal Transition May Be Early Predictors of Barrett's Esophagus Malignant Progression.

Barrett's esophagus is the major risk factor for esophageal adenocarcinoma. It has a low but non-neglectable risk, high surveillance costs and no reliable risk stratification markers. We sought to identify early biomarkers, predictive of Barrett's malignant progression, using a meta-analysis approach on gene expression data. This in silico strategy was followed by experimental validation in a cohort of patients with extended follow up from the Instituto Português de Oncologia de Lisboa de Francisco Gentil EPE (Portugal). Bioinformatics and systems biology approaches singled out two candidate predictive markers for Barrett's progression, CYR61 and TAZ. Although previously implicated in other malignancies and in epithelial-to-mesenchymal transition phenotypes, our experimental validation shows for the first time that CYR61 and TAZ have the potential to be predictive biomarkers for cancer progression. Experimental validation by reverse transcriptase quantitative PCR and immunohistochemistry confirmed the up-regulation of both genes in Barrett's samples associated with high-grade dysplasia/adenocarcinoma. In our cohort CYR61 and TAZ up-regulation ranged from one to ten years prior to progression to adenocarcinoma in Barrett's esophagus index samples. Finally, we found that CYR61 and TAZ over-expression is correlated with early focal signs of epithelial to mesenchymal transition. Our results highlight both CYR61 and TAZ genes as potential predictive biomarkers for stratification of the risk for development of adenocarcinoma and suggest a potential mechanistic route for Barrett's esophagus neoplastic progression.

Pediatric liver transplantation: 10 years of experience at a single center in Brazil.

OBJECTIVES: To evaluate the first 10 years' experience of the liver transplantation department at the Alfa Institute, Hospital das Clínicas da Universidade Federal de Minas Gerais, Brazil. METHODS: A descriptive study, based on a retrospective analysis of 84 children and adolescents enrolled on a liver transplantation waiting list, from March 1995 to January 2006, based on the following variables: age, etiology of underlying liver disease, Child-Pugh, Malatack, model for end-stage liver disease (MELD) and pediatric end-stage liver disease (PELD) scores, time on waiting list, complications and survival after the procedure. RESULTS: Forty children had 42 liver transplants. Twenty six died while on the waiting list. Biliary atresia was the most frequent indication for transplant. The median age was 6.6 years (ranging from 1.9 to 16.8 years). Post liver transplant mortality was 32.5% (13 of 40 children). The median time on the liver transplant waiting list was 291 days. Complications related to the graft occurred in 24 of 42 transplants (57.1%), including vascular complications (30.8%), with thrombosis of the hepatic artery being the most frequent (16.6%); acute rejection occurred in 16.6%. CONCLUSIONS: The overall results are similar to what can be found in the literature with relation to indications and post-transplant survival. However, there were elevated rates of complications unrelated to the graft and of complications involving the hepatic artery.

Transplante hepático pediátrico: experiência de 10 anos em um único centro no Brasil / Pediatric liver transplantation: 10 years of experience at a single center in Brazil

OBJETIVOS: Avaliar a experiência dos primeiros 10 anos de transplante hepático em crianças e adolescentes do Serviço de Transplante Hepático do Instituto Alfa de Gastroenterologia do Hospital das Clínicas da Universidade Federal de Minas Gerais. MÉTODOS: Estudo descritivo de 84 pacientes menores de 18 anos inscritos em lista para transplante, no período de março de 1995 a janeiro de 2006, quanto às seguintes variáveis: idade, indicação do transplante, escores de gravidade (Child-Pugh, Malatack, PELD/MELD), tempo de espera em lista, complicações pós-operatórias e sobrevida. RESULTADOS: De 84 pacientes inscritos, 40 foram submetidos ao transplante, ocorrendo dois retransplantes. Vinte e seis faleceram na lista de espera. A atresia biliar foi a indicação mais freqüente. A mediana da idade no momento do transplante foi de 6,6 anos (variou de 1,9 a 16,8 anos). A mortalidade no pós-transplante foi de 32,5 por cento (13 de 40 crianças). O tempo de espera em lista dos 40 pacientes transplantados apresentou mediana de 291 dias. As complicações relacionadas ao enxerto ocorreram em 24 dos 42 transplantes (57,1 por cento), sendo que as vasculares representaram 30,8 por cento, prevalecendo a trombose da artéria hepática (16,6 por cento); episódio de rejeição aguda ocorreu em 16,6 por cento dos casos. CONCLUSÃO: Os resultados encontrados são semelhantes ao que é observado na literatura em relação às indicações e sobrevida no pós-transplante. No entanto, houve elevada taxa de complicações não relacionadas ao enxerto e daquelas relacionadas à artéria hepática.

OBJECTIVES: To evaluate the first 10 years' experience of the liver transplantation department at the Alfa Institute, Hospital das Clínicas da Universidade Federal de Minas Gerais, Brazil. METHODS: A descriptive study, based on a retrospective analysis of 84 children and adolescents enrolled on a liver transplantation waiting list, from March 1995 to January 2006, based on the following variables: age, etiology of underlying liver disease, Child-Pugh, Malatack, model for end-stage liver disease (MELD) and pediatric end-stage liver disease (PELD) scores, time on waiting list, complications and survival after the procedure. RESULTS: Forty children had 42 liver transplants. Twenty six died while on the waiting list. Biliary atresia was the most frequent indication for transplant. The median age was 6.6 years (ranging from 1.9 to 16.8 years). Post liver transplant mortality was 32.5 percent (13 of 40 children). The median time on the liver transplant waiting list was 291 days. Complications related to the graft occurred in 24 of 42 transplants (57.1 percent), including vascular complications (30.8 percent), with thrombosis of the hepatic artery being the most frequent (16.6 percent); acute rejection occurred in 16.6 percent. CONCLUSIONS: The overall results are similar to what can be found in the literature with relation to indications and post-transplant survival. However, there were elevated rates of complications unrelated to the graft and of complications involving the hepatic artery.