GCIMP

GCIMP, often written as G-CIMP, refers to the Glioma CpG Island Methylator Phenotype, a molecular classification within gliomas identified through genome-wide DNA methylation analysis. The G-CIMP phenotype is defined by widespread hypermethylation of CpG islands in promoter regions and is closely linked to mutations in the IDH1 or IDH2 genes. This methylation signature helps distinguish a subset of gliomas from tumors without this pattern and has been incorporated into discussions of molecular glioma taxonomy.

Molecular features of GCIMP tumors include extensive promoter methylation affecting numerous genes, which is thought to contribute to altered gene expression and a characteristic biology. Within the GCIMP group, subcategories such as GCIMP-high and GCIMP-low have been described, reflecting differences in the density of methylation. Generally, GCIMP-high tumors tend to have a more favorable prognosis than GCIMP-low tumors, and both tend to have better outcomes than non-GCIMP gliomas with IDH mutations, though exact prognostic implications can vary with additional factors.

Clinical significance of GCIMP lies in its association with younger patient age at diagnosis and improved overall survival relative to non-GCIMP gliomas, making methylation status a useful prognostic and potentially predictive biomarker. As DNA methylation profiling becomes more integrated into routine diagnostics, GCIMP status contributes to refining glioma classification and guiding clinical decision-making.

Detection methods include DNA methylation arrays (such as Infinium platforms) and bisulfite sequencing, which identify the CpG island methylation pattern characteristic of GCIMP. See also glioma, IDH mutation, CpG island methylator phenotype, DNA methylation profiling.