Colorectal cancer is one of the most common cancers in the world. Histological staging is efficient but combination with molecular markers may improve tumors classification. Gene expression profiles have been defined as prognosis predictors among stage II and III tumors but their implementation in medical practice remains controversial. Stage-II tumors have been recognized as a heterogeneous group and high-risk morphologic features have been retained as justifying adjuvant chemotherapy. We propose here the investigation of clinical features and expression profiles from stage II and stage III colon carcinomas without DNA mismatch repair defect. A series of 130 colon cancer samples was retained. Expression profiles were established on oligonucleotide microarrays and processed in the R/Bioconductor environment. Hierarchical then supervised analyses were successively performed applying the data-sampling approach. A molecular signature of seven genes was found to cluster stage III tumors with an adjusted p-values lower than 10^-10. A subgroup of stage-II tumors aggregated this cluster in both series. No correlation was found between with the disease severity but the function of the discriminating genes suggests that tumors have been classified according to their putative response to adjuvant targeted or classic therapies. Further pharmacogenetic studies might document this observation.
A seven-gene signature aggregates a subgroup of stage II colon cancers with stage III.
Sex, Age, Specimen partView Samples
Differentially expressed genes between 171 human soft tissue sarcomas with complex genomics
From PTEN loss of expression to RICTOR role in smooth muscle differentiation: complex involvement of the mTOR pathway in leiomyosarcomas and pleomorphic sarcomas.
Sex, Specimen part, Cell lineView Samples
Analysis of primary bovine aortic endothelial cells treated for 24 hours with TGF-beta 1 5 ng/ml. TGF-beta 1 has been shown to induce endothelial-to-mesenchymal transition (EndoMT) and to be implicated in differentiation of endothelial cells into smooth muscle-like cells as occurred in vascular neointimal formation.
LOXL4 is induced by transforming growth factor β1 through Smad and JunB/Fra2 and contributes to vascular matrix remodeling.
Specimen partView Samples
For this study, we selected, from the French Sarcoma Group (FSG) database, soft tissue sarcomas with no recurrent chromosomal translocations and for which a frozen tissue of the untreated primary tumor was available. Three hundred and ten sarcomas have been studied. They are split in two cohorts.
Validated prediction of clinical outcome in sarcomas and multiple types of cancer on the basis of a gene expression signature related to genome complexity.
Specimen part, Disease, TimeView Samples
Dominant gain-of-function alleles of Arabidopsis phytochrome B were recently shown to confer light-independent, constitutive photomorphogenic (cop) phenotypes to transgenic plants (Su & Lagarias 2007 Plant Cell 19, 2124-2139). In the present study, comparative transcript profiling experiments were performed to assess whether the pattern of gene expression regulated by these alleles accurately reflects the process of photomorphogenesis in wild-type Arabidopsis. Whole genome transcriptional profiles of dark-grown phyAphyB seedlings expressing the Y276H mutant of phyB (YHB) revealed that YHB reprograms about 13% of the Arabidopsis transcriptome in a light-independent manner. The YHB-regulated transcriptome proved qualitatively similar to, but quantitatively greater than those of wild-type seedlings grown under 15 or 50 umol m-2 m-1 continuous red light (Rc). Among the 2977 genes statistically significant two-fold (SSTF) regulated by YHB in the absence of light include those encoding components of the photosynthetic apparatus, tetrapyrrole/pigment biosynthetic pathways and early light-responsive signaling factors. Approximately 80% of genes SSTF regulated by Rc were also YHB-modulated. Expression of a notable subset of 346 YHB-regulated genes proved to be strongly attenuated by Rc, indicating compensating regulation by phyC-E and/or other Rc-dependent processes. Since the majority of these 346 genes are regulated by the circadian clock, these results suggest that phyA- and phyB-independent light signaling pathway(s) strongly influence clock output. Together with the unique plastid morphology of dark-grown YHB seedlings, these analyses indicate that the YHB mutant induces constitutive photomorphogenesis via faithful reconstruction of phyB signaling pathways in a light-independent fashion.
A light-independent allele of phytochrome B faithfully recapitulates photomorphogenic transcriptional networks.
No sample metadata fieldsView Samples
From a clinical and molecular perspective, colon cancer (CC) is a heterogeneous disease but to date no classification based on high-density transcriptome data has been established. The aim of this study was to build up a robust molecular classification ofmRNA expression profiles (Affymetrix U133Plus2) ofa large series of 443 CC and 19 non-tumoral colorectal mucosas, and to validate it on an independent serie of 123 CC and 906 public dataset.We identified and validated six molecular subtypes in this large cohort as a combination of multiple molecular processes that complement current disease stratification based on clinicopathological variables and molecular markers. The biological relevance of these subtypes was consolidated by significant differences in survival. These insights open new perspectives for improving prognostic models and targeted therapies.
Gene expression classification of colon cancer into molecular subtypes: characterization, validation, and prognostic value.