0000000000300076
AUTHOR
Caroline Chapusot
Structure of MHC class I and class II cDNAs and possible immunodeficiency linked to class II expression in the Mexican axolotl
Despite the fact that the axolotl (Ambystoma spp. a urodele amphibian) displays a large T-cell repertoire and a reasonable B-cell repertoire, its humoral immune response is slow (60 days), non-anamnestic, with a unique IgM class. The cytotoxic immune response is slow as well (21 days) with poor mixed lymphocyte reaction stimulation. Therefore, this amphibian can be considered as immunodeficient. The reason for this subdued immune response could be an altered antigenic presentation by major histocompatibility complex (MHC) molecules. This article summarizes our work on axolotl MHC genes. Class I genes have been characterized and the cDNA sequences show a good conservation of non-polymorphic …
Patients with colorectal tumors with microsatellite instability and large deletions in HSP110 T17 have improved response to 5-fluorouracil–based chemotherapy.
Background & Aims Patients with colorectal tumors with microsatellite instability (MSI) have better prognoses than patients with tumors without MSI, but have a poor response to 5-fluorouracil–based chemotherapy. A dominant-negative form of heat shock protein (HSP)110 (HSP110DE9) expressed by cancer cells with MSI, via exon skipping caused by somatic deletions in the T 17 intron repeat, sensitizes the cells to 5-fluorouracil and oxaliplatin. We investigated whether HSP110 T 17 could be used to identify patients with colorectal cancer who would benefit from adjuvant chemotherapy with 5-fluorouracil and oxaliplatin. Methods We characterized the interaction between HSP110 and HSP110DE9 using su…
HSP110 T17 simplifies and improves the microsatellite instability testing in patients with colorectal cancer
IF 5.65; International audience; Background Every colorectal cancer (CRC) patient should be tested for microsatellite instability (MSI, a marker for defective DNA mismatch repair) as a first screen for Lynch syndrome (LS). In this study, we investigated whether it may be possible to improve the detection of MSI in CRC. We examined whether the HT17 DNA repeat (critical for correct splicing of the chaperone HSP110) might constitute a superior marker for diagnosis of the MSI phenotype in patients with CRC compared with the standard panel of markers (pentaplex).Methods The HT17 polymorphism was analysed in germline DNA from 1037 multi-ethnic individuals. We assessed its sensitivity and specific…
Copy number variations inDCC/18q andERBB2/17q are associated with disease-free survival in microsatellite stable colon cancer
We conducted a prospective study to assess the prognostic impact of selected copy number variations (CNVs) in stage II-III microsatellite stable (MSS) colon cancer. A total of 401 patients were included from 01/2004 to 01/2009. The CNVs in 8 selected target genes, DCC/18q, EGFR/7p, TP53/17p, BLK/8p, MYC/8q, APC/5q, ERBB2/17q, and STK6/20q, were detected using a quantitative multiplex polymerase chain reaction of short fluorescent fragment (QMPSF) method. The primary end-point was the impact of the CNVs on the 4-year disease-free survival (DFS). The recurrence rate at 4 years was 20.9%, corresponding to 14% stage II patients vs 31% stage III patients (p<0.0001). The 4-year DFS was significan…
Additional file 1: Table S1. of Analysis of RET promoter CpG island methylation using methylation-specific PCR (MSP), pyrosequencing, and methylation-sensitive high-resolution melting (MS-HRM): impact on stage II colon cancer patient outcome
Primer sequences and conditions. Primer pairs were designed near the putative transcriptional start site. (DOCX 17 kb)
Promoter CpG island methylation of RET predicts poor prognosis in stage II colorectal cancer patients
Abstract Improved prognostic stratification of patients with TNM stage II colorectal cancer (CRC) is desired, since 20–30% of high-risk stage II patients may die within five years of diagnosis. This study was conducted to investigate REarranged during Transfection ( RET ) gene promoter CpG island methylation as a possible prognostic marker for TNM stage II CRC patients. The utility of RET promoter CpG island methylation in tumors of stage II CRC patients as a prognostic biomarker for CRC related death was studied in three independent series (including 233, 231, and 294 TNM stage II patients, respectively) by using MSP and pyrosequencing. The prognostic value of RET promoter CpG island methy…
Identification of novel, clonally stable, somatic mutations targeting transcription factors PAX5 and NKX2-3, the epigenetic regulator LRIF1, and BRAF in a case of atypical B-cell chronic lymphocytic leukemia harboring a t(14;18)(q32;q21)
Diagnosis of B-cell chronic lymphocytic leukemia (B-CLL) is usually straightforward, involving clinical, immunophenotypic (Matutes score), and (immuno)genetic analyses (to refine patient prognosis for treatment). CLL cases with atypical presentation (e.g., Matutes ≤ 3) are also encountered, and for these diseases, biology and prognostic impact are less clear. Here we report the genomic characterization of a case of atypical B-CLL in a 70-yr-old male patient; B-CLL cells showed a Matutes score of 3, chromosomal translocation t(14;18)(q32;q21) (BCL2/IGH), mutated IGHV, deletion 17p, and mutations in BCL2, NOTCH1 (subclonal), and TP53 (subclonal). Quite strikingly, a novel PAX5 mutation that w…
Development of primary early-onset colorectal cancers due to biallelic mutations of the FANCD1/BRCA2 gene
International audience; Fanconi anaemia (FA) is characterized by progressive bone marrow failure, congenital anomalies, and predisposition to malignancy. In a minority of cases, FA results from biallelic FANCD1/BRCA2 mutations that are associated with early-onset leukaemia and solid tumours. Here, we describe the clinical and molecular features of a remarkable family presenting with multiple primary colorectal cancers (CRCs) without detectable mutations in genes involved in the Mendelian predisposition to CRCs. We unexpectedly identified, despite the absence of clinical cardinal features of FA, a biallelic mutation of the FANCD1/BRCA2 corresponding to a frameshift alteration (c.1845_1846del…
Analysis of RET promoter CpG island methylation using methylation-specific PCR (MSP), pyrosequencing, and methylation-sensitive high-resolution melting (MS-HRM): impact on stage II colon cancer patient outcome.
Background Already since the 1990s, promoter CpG island methylation markers have been considered promising diagnostic, prognostic, and predictive cancer biomarkers. However, so far, only a limited number of DNA methylation markers have been introduced into clinical practice. One reason why the vast majority of methylation markers do not translate into clinical applications is lack of independent validation of methylation markers, often caused by differences in methylation analysis techniques. We recently described RET promoter CpG island methylation as a potential prognostic marker in stage II colorectal cancer (CRC) patients of two independent series. Methods In the current study, we analy…
Axolotl MHC class II β chain: predominance of one allele and alternative splicing of the β1 domain
The axolotl MHC is composed of multiple polymorphic class I loci linked to class II B loci. In this report, evidence of the existence of one class II B locus (Amme-DAB) that codes for two different transcripts is given. A 2.1-kb transcript is translated to a complete β chain and a shorter transcript of 1.8 kb encodes a molecule lacking the β1 domain. For two complete class II B mRNA synthesized, up to one mRNA devoid of the β1 domain is synthesized. Alternative splicing involving a peptide binding domain at a class II B locus evidenced in axolotl (Ambystoma mexicanum) is also observed for A. trigrinum, the tiger salamander. Very little variability is found among various axolotl MHC class II…
Mutations in the RAS-MAPK, PI(3)K (phosphatidylinositol-3-OH kinase) signaling network correlate with poor survival in a population-based series of colon cancers
The RAS-MAPK, PI (3)K signaling pathways form a network that play a central role in tumorigenesis. The BRAF, KRAS and PI3KCA genes code 3 partners of this network and have been found to be activated by mutation in colorectal cancer; these mutations lead to unrestricted cell growth. We evaluated the clinicopathological features and the prognosis of patients with activated-network colon cancers in a population-based study. A total of 586 colon adenocarcinomas were evaluated using sequencing for mutations of KRAS and PI3KCA, and allelic discrimination for mutation of BRAF. Clinicopathological characteristics were correlated to the risk of bearing a mutation of the network using logistic regres…
Cancers du côlon : prise en charge moléculaire
Resume Le demembrement moleculaire des cancers et en particulier des cancers colorectaux conduit a des prises en charge de plus en plus adaptees et de plus en plus complexes. Ce demembrement a abouti a de nombreuses classifications et finalement a une classification moleculaire consensuelle en 2015. Cette classification consensuelle reste pour l’instant non utilisable au quotidien. Plusieurs facteurs moleculaires (statut MSS/MSI, statut BRAF, statut RAS) sont desormais indispensables a la prise en charge du cancer colorectal que ce soit en situation adjuvante ou metastatique. D’autres facteurs tels que le statut HER2 et l’expression de mir-31-3p sont regulierement pris en compte au cas par …
A case report of Muir-Torre syndrome in a woman with breast cancer and MSI-Low skin squamous cell carcinoma.
IF 1.590; International audience; Background: The tumor spectrum in the Lynch syndrome is well defined, comprising an increased risk of developing colonic and extracolonic malignancies. Muir-Torre syndrome is a variant with a higher risk of skin disease. Patients have been described carrying mutations in the mismatch repair genes and presenting tumors with unusual histology or affected organ not part of the Lynch syndrome spectrum. Hence, the real link between Lynch syndrome, or Muir-Torre syndrome, and these tumors remains difficult to assess.Case presentation: We present the case of a 45-year-old-woman, diagnosed with breast cancer at 39 years of age and skin squamous cell carcinoma (SCC)…
Why do results conflict regarding the prognostic value of the methylation status in colon cancers? The role of the preservation method.
Abstract Background 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. Methods Couples of matched cryo-preserved and FFPE samples from 40 colon adenocarcinomas were analyzed. Rates of bisulfite conversion and levels of methylation of …
Hypermethylator phenotype in sporadic colon cancer: study on a population-based series of 582 cases.
Abstract The CpG island methylator phenotype (CIMP) is a distinct phenotype in colorectal cancer, associated with specific clinical, pathologic, and molecular features. However, most of the studies stratified methylation according to two subgroups (CIMP-High versus No-CIMP/CIMP-Low). In our study, we defined three different subgroups of methylation (No-CIMP, CIMP-Low, and CIMP-High) and evaluated the prognostic significance of methylation status on a population-based series of sporadic colon cancers. A total of 582 colon adenocarcinomas were evaluated using methylation-specific PCR for 5 markers (hMLH1, P16, MINT1, MINT2, and MINT31). No-CIMP status was defined as no methylated locus, CIMP-…