Linked Life Data

17086168

Source:http://linkedlifedata.com/resource/pubmed/id/17086168

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2006-12-15
pubmed:abstractText
Downregulation of p27 (cyclin-dependent kinase inhibitor-1B, CDKN1B or KIP1) is caused by increased ubiquitin-mediated proteasomal degradation in colorectal cancer, and has been associated with poor prognosis. CpG island methylator phenotype (CIMP) is a phenotype of colorectal cancer with extensive promoter methylation, and associated with high degree of microsatellite instability (MSI-H) and BRAF mutations. We have recently shown that both CIMP and MSI-H are inversely associated with downregulation of p21 (CDKN1A or CIP1), another cyclin-dependent kinase inhibitor. However, no study to date has examined relationship between p27 and CIMP status in colorectal cancer. Using MethyLight assays, we measured DNA methylation in five CIMP-specific gene promoters {CACNA1G, CDKN2A (p16), CRABP1, MLH1 and NEUROG1} in 706 colorectal cancer samples obtained from two large prospective cohorts. Among the 706 tumors, 112 (16%) were CIMP-high tumors with >or=4/5 methylated promoters. We assessed p27 and p53 expressions by immunohistochemistry. Loss of nuclear p27 expression {observed in 231 tumors (33%)} was significantly associated with CIMP-high, MSI-H and BRAF mutations, and these associations were much more pronounced among p53-negative tumors than p53-positive tumors. When CIMP-high and non-CIMP-high tumors were stratified by MSI status (or KRAS and BRAF status), CIMP-high and MSI-H (but not BRAF mutations) were still significantly associated with nuclear p27 loss. Nuclear p27 loss did not appear to be directly related to CDKN2A (p16) methylation. We conclude that downregulation of nuclear p27 is associated with CIMP-high and MSI-H in colorectal cancer. These associations are stronger among p53 wild-type tumors, implying important interplay of p27 and p53 functions (or dysfunctions) in the development of various molecular subtypes of colorectal cancer.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0893-3952
pubmed:author
pubmed:issnType
Print
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15-22
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed-meshheading:17086168-Cell Nucleus, pubmed-meshheading:17086168-Cohort Studies, pubmed-meshheading:17086168-Colorectal Neoplasms, pubmed-meshheading:17086168-CpG Islands, pubmed-meshheading:17086168-Cyclin-Dependent Kinase Inhibitor p16, pubmed-meshheading:17086168-Cyclin-Dependent Kinase Inhibitor p27, pubmed-meshheading:17086168-DNA Methylation, pubmed-meshheading:17086168-Down-Regulation, pubmed-meshheading:17086168-Female, pubmed-meshheading:17086168-Gene Expression Regulation, Neoplastic, pubmed-meshheading:17086168-Genes, ras, pubmed-meshheading:17086168-Humans, pubmed-meshheading:17086168-Immunohistochemistry, pubmed-meshheading:17086168-Intracellular Signaling Peptides and Proteins, pubmed-meshheading:17086168-Male, pubmed-meshheading:17086168-Microsatellite Instability, pubmed-meshheading:17086168-Phenotype, pubmed-meshheading:17086168-Polymerase Chain Reaction, pubmed-meshheading:17086168-Prospective Studies, pubmed-meshheading:17086168-Proto-Oncogene Proteins B-raf, pubmed-meshheading:17086168-Registries, pubmed-meshheading:17086168-Tumor Suppressor Protein p53, pubmed-meshheading:17086168-United States
pubmed:year
2007
pubmed:articleTitle
Loss of nuclear p27 (CDKN1B/KIP1) in colorectal cancer is correlated with microsatellite instability and CIMP.
pubmed:affiliation
Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA. shuji_ogino@dfci.harvard.edu
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural