Multiregional assessment of CIMP in primary colorectal cancers: Phenotype concordance but marker variability.
Int J Cancer
; 148(7): 1652-1657, 2021 04 01.
Article
in En
| MEDLINE
| ID: mdl-33284993
ABSTRACT
Intratumor heterogeneity of colorectal cancers (CRCs) is manifested both at the genomic and epigenomic levels. Early genetic aberrations in carcinogenesis are clonal and present throughout the tumors, but less is known about the heterogeneity of the epigenetic CpG island methylator phenotype (CIMP). CIMP characterizes a subgroup of CRCs thought to originate from specific precursor lesions, and it is defined by widespread DNA methylation within promoter regions. In this work, we investigated CIMP in two to four multiregional samples from 30 primary tumors (n = 86 samples) using the consensus Weisenberger gene panel (CACNA1G, IGF2, NEUROG1, RUNX3 and SOCS1). Twenty-nine of 30 tumors (97%) showed concordant CIMP status in all samples, and percent methylated reference (PMR) values of all five markers had higher intertumor than intratumor variation (P value = 1.5e-09). However, a third of the CIMP+ tumors exhibited discrepancies in methylation status in at least one of the five gene markers. To conclude, CIMP status was consistent within primary CRCs, and it is likely a clonal phenotype. However, spatial discordances of the individual genes suggest that large-scale analysis of multiregional samples could be of interest for identifying CIMP markers that are robust to intratumor heterogeneity.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Biomarkers, Tumor
/
CpG Islands
/
DNA Methylation
Type of study:
Prognostic_studies
Limits:
Aged
/
Aged80
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Int J Cancer
Year:
2021
Type:
Article
Affiliation country:
Norway