Why do results conflict regarding the prognostic value of the methylation status in colon cancers? the role of the preservation method

<p>Abstract</p> <p>Background</p> <p>In colorectal carcinoma, extensive gene promoter hypermethylation is called the CpG island methylator phenotype (CIMP). Explaining why studies on CIMP and survival yield conflicting results is essential. Most experiments to measure DNA methylation rely on the sodium bisulfite conversion of unmethylated cytosines into uracils. No study has evaluated the performance of bisulfite conversion and methylation levels from matched cryo-preserved and Formalin-Fixed Paraffin Embedded (FFPE) samples using pyrosequencing.</p> <p>Methods</p> <p>Couples of matched cryo-preserved and FFPE samples from 40 colon adenocarcinomas were analyzed. Rates of bisulfite conversion and levels of methylation of <it>LINE-1, MLH1 </it>and <it>MGMT </it>markers were measured.</p> <p>Results</p> <p>For the reproducibility of bisulfite conversion, the mean of bisulfite-to-bisulfite standard deviation (SD) was 1.3%. The mean of run-to-run SD of PCR/pyrosequencing was 0.9%. Of the 40 DNA couples, only 67.5%, 55.0%, and 57.5% of FFPE DNA were interpretable for <it>LINE-1, MLH1</it>, and <it>MGMT </it>markers, respectively, after the first analysis. On frozen samples the proportion of well converted samples was 95.0%, 97.4% and 87.2% respectively. For DNA showing a total bisulfite conversion, 8 couples (27.6%) for <it>LINE-1</it>, 4 couples (15.4%) for <it>MLH1 </it>and 8 couples (25.8%) for <it>MGMT </it>displayed significant differences in methylation levels.</p> <p>Conclusions</p> <p>Frozen samples gave reproducible results for bisulfite conversion and reliable methylation levels. FFPE samples gave unsatisfactory and non reproducible bisulfite conversions leading to random results for methylation levels. The use of FFPE collections to assess DNA methylation by bisulfite methods must not be recommended. This can partly explain the conflicting results on the prognosis of CIMP colon cancers.</p

Identification and verification of heat shock protein 60 as a potential serum marker for colorectal cancer

Colorectal cancer (CRC) is a major public health issue worldwide, and novel tumor markers may contribute to its efficient management by helping in early detection, prognosis or surveillance of disease. The aim of our study was to identify new serum biomarkers for CRC, and we followed a phased biomarker discovery and validation process to obtain an accurate preliminary assessment of potential clinical utility. We compared colonic tumors and matched normal tissue from 15 CRC patients, using two-dimensional difference gel electrophoresis (2D-DIGE), and identified 17 proteins that had significant differential expression. These results were further confirmed by western blotting for heat shock protein (HSP) 60, glutathione-S-transferase Pi, α-enolase, T-complex protein 1 subunit β, and leukocyte elastase inhibitor, and by immunohistochemistry for HSP60. Using mAbs raised against HSP60, we developed a reliable (precision of 5–15%) and sensitive (0.3 ng·mL−1) immunoassay for the detection of HSP60 in serum. Elevated levels of HSP60 were found in serum from CRC patients in two independent cohorts; the receiver-operating characteristic curve obtained in 112 patients with CRC and 90 healthy controls had an area under the curve (AUC) of 0.70, which was identical to the AUC of carcinoembryonic antigen. Combination of serum markers improved clinical performance: the AUC of a three-marker logistic regression model combining HSP60, carcinoembryonic antigen and carbohydrate antigen 19-9 reached 0.77. Serum HSP60 appeared to be more specific for late-stage CRC; therefore, future studies should evaluate its utility for determining prognosis or monitoring therapy rather than early detection

Etude du micro-environnement du cancer colorectal chez l'homme (approche par Tissue Micro Arrays (puces tissulaires))

DIJON-BU Médecine Pharmacie (212312103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Statut mutationnel de BRAF (méthode de détection et intérêt dans la prise en charge des cancers colorectaux de type MSI-H, étude sur une série de 49 patients opérés d'un adénocarcinome colorectal dans le département de la Côte d'Or)

DIJON-BU Médecine Pharmacie (212312103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Evaluation du statut P53 (étude immunhistochimique et moléculaire d'une série de 90 patients opérés d'un cancer colorectal dans le département de la Côte d'Or)

DIJON-BU Médecine Pharmacie (212312103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Etude des mutants rares du gène KRAS (génotypage des codons 61 et 146 sur une série de 250 patients porteurs d'une adénocarcinome colique)

DIJON-BU Médecine Pharmacie (212312103) / SudocSudocFranceF

Altérations génétiques et épigénétiques dans le cancer colique sporadique

Les cancers sont le plus souvent la conséquence d un défaut des voies de régulations impliquées dans la survie ou la mort cellulaire. Nous avons pu démontrer sur une base de population de 586 adénocarcinomes coliques, suivis par le registre bourguignon des cancers digestifs que la mutation activatrice d au moins un des trois gènes de la voie des MAP Kinases (KRAS, BRAF, PI3KCA) était associée a une moins bonne survie chez les patients porteurs d une tumeur sans instabilité des microsatellites. Nous avons également analysé sur cette base de population la méthylation de l ADN (caractérisation du phénotype CpG Island Methylator Phenotype CIMP). Trois groupes de méthylation ont été définis (No-CIMP, CIMP-Low, CIMP-High). Les cancers MSS/No-CIMP et MSS/CIMP-Low montraient des caractéristiques cliniques et génétiques similaires mais influençaient la survie de façon différente. Plus le niveau de méthylation était élevé, moins bonne était la survie des patients. Cette étude souligne l effet pronostique péjoratif de la méthylation chez les patients MSS et la nécessité d identifier les 3 groupes de méthylation. Ces travaux tirent leur importance de l utilisation récente, dans le traitement du cancer, de thérapeutiques dites ciblées dirigées des protéines impliquées dans la transduction du signal du milieu extracellulaire vers le milieu intracellulaire. L identification des mécanismes d activation des voies de signalisation et la caractérisation des altérations épigénétiques impliquées dans le cancer colique représentent donc des étapes fondamentales dans la connaissance des facteurs moléculaires pouvant moduler la prise en charge thérapeutique des patients.Cancer cells are often the result of alterations in signalling pathways implicated in cell survival or apoptosis. We successfully demonstrated in a population base of 586 colon adenocarcinomas, followed by the cancer registry of Burgundy, that activating mutation of at least one of the three genes from the MAPK signalling pathway (KRAS, BRAF, PI3KCA) was associated with a lower survival in patients bearing a tumour without microsatellite instability. In a second study, DNA Methylation, an epigenetic alteration, was evaluated in the population base (characterization of the CpG Island Methylator Phenotype). Three subgroups of methylation phenotype were identified (No-CIMP, CIMP-Low, and CIMP-High). The clinico-pathological features of cancers with MSS/No-CIMP and MSS/CIMP-Low were quite similar, but they affected survival to different degrees. The higher the level of methylation, the poorer the survival. Our work clearly showed the prognostic effect of methylation in MSS patients and the need to distinguish between the 3 groups of CIMP. These studies are all the more important since the recent use of targeted therapies against proteins from the signal transduction system have recently been used in cancer treatment. The identification of activating mechanisms of signalling pathways and the characterisation of epigenetic alterations involved in colon cancer are fundamental to the understanding of the molecular factors involved in colorectal cancer. Knowledge of these will have an impact on patient response and follow-up.DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF

Using a heating cable within the abdomen to make hyperthermic intraperitoneal chemotherapy easier: Feasibility and safety study in a pig model.

International audienceBACKGROUND: Hyperthermic intraperitoneal chemotherapy (HIPEC) is a complex, expensive and time-consuming procedure. Despite its good results in the treatment of peritoneal carcinomatosis, these factors have precluded the wider use of this procedure around the world. We hypothesized that HIPEC could be performed by heating the liquid within the abdomen and thus avoiding the need for an external heating circuit and a pump. The aim of this study was to assess the feasibility and safety of an internal heating device for hyperthermic intraperitoneal chemotherapy in an experimental model. METHODS: Four large-white pigs underwent one-hour open intraperitoneal hyperthermia with closed abdomen using this new device. Constant stirring of the liquid around the viscera was performed in the first three animals, but not in the fourth one. At the end of the procedure, all of the viscera were carefully examined to look for thermal injury. Any lesion or doubtful area was removed and sent to pathologic examination. RESULTS: No adverse events occurred during surgery in any of the animals. A temperature of 42 degrees C was reached in an average time of 14min and maintained homogeneously between 42 degrees C and 43 degrees C for one hour. No visceral injury was detected in the first three animals. Three foci of thermal injury to the mucosa were detected in the absence of stirring (fourth animal). CONCLUSION: Heating the solution within the abdomen during hyperthermic intraperitoneal chemotherapy is feasible, safe and achieves perfect thermal homogeneity. This device provides a time-saving inexpensive way to perform intraperitoneal hyperthermic chemotherapy

Cancers : pronostics à long terme

L’estimation du « sur-risque » de décès auquel est exposé une personne ayanteu un cancer est une problématique qui intéresse à la fois les patients et lesprofessionnels de l’assurance quand il s’agit de contracter un prêt et de calculerla prime de ce contrat. Le niveau de « sur-risque » peut être évalué enfonction de l’âge, du sexe du patient, et parfois des caractéristiques de latumeur. Les données européennes récentes sur l’espérance de vie de patientsatteints de cancer permettent d’estimer ce « sur-risque » ou « surmortalité »associés aux différentes localisations cancéreuses