Gastric carcinoma (GC) is one of the human cancers in which promoter CpG island hypermethylation is frequently found. CpG island methylator phenotype (CIMP) refers to a subset of GCs which harbor concordant methylation of multiple promoter CpG island loci. However, little is known regarding clinicopathological features of CIMP-positive (CIMP-high) GC. Our study aimed to characterize clinicopathological features of CIMP-high GC. We analyzed 196 cases of GCs for their methylation status in 16 cancer-specific CpG island loci using MethyLight assay and arbitrarily defined CIMP-high GC as those with methylation at 13 or more CpG island loci. With exclusion of microsatellite instability-positive GC and EBV-positive GC from the analysis, CIMP-high GC (n∈=∈10, 6.7%) demonstrated tendency toward higher cancer stage, infiltrative growth type, poor differentiation, and diffuse or mixed type of Lauren classification. CIMP-high GC showed significantly shortened survival compared with that of CIMP-negative GC. When CIMP-negative GC (methylation at 12 or less) was divided into CIMP-intermediate and CIMP-low (methylation at one or none), CIMP-low exhibited better clinical outcome than CIMP-intermediate. Hypermethylation at 14 CpG island loci or more was closely associated with poor clinical outcome and found to be an independent prognostic factor. Our findings that CIMP-high GCs were featured with characteristic clinicopathological parameters, including poor prognosis are distinct from previous studies. More extensive, large-scaled study is necessary to validate the findings of the present study.
All Science Journal Classification (ASJC) codes
- Pathology and Forensic Medicine
- Molecular Biology
- Cell Biology