0000000000787718
AUTHOR
Pratyaksha Wirapati
Integrative Genome-Scale DNA Methylation Analysis of a Large and Unselected Cohort Reveals 5 Distinct Subtypes of Colorectal Adenocarcinomas
BACKGROUND & AIMS: Colorectal cancer is an epigenetically heterogeneous disease, however, the extent and spectrum of the CpG island methylator phenotype (CIMP) is not clear. METHODS: Genome-scale methylation and transcript expression were measured by DNA Methylation and RNA expression microarray in 216 unselected colorectal cancers, and findings were validated using The Cancer Genome Atlas 450K and RNA sequencing data. Mutations in epigenetic regulators were assessed using CIMP-subtyped Cancer Genome Atlas exomes. RESULTS: CIMP-high cancers dichotomized into CIMP-H1 and CIMP-H2 based on methylation profile. KRAS mutation was associated significantly with CIMP-H2 cancers, but not CIMP-H1 can…
Association of MAPK signaling subtypes with prognostic benefit for bevacizumab in left-sided metastatic colorectal cancer (mCRC) patients treated with FOLFIRI + cetuximab / bevacizumab (FIRE-3 trial).
3584 Background: We investigated the role of the MAPK pathway by mRNA expression profiles in microarrays of the FIRE-3 trial as it was formerly associated with prognosis. Methods: 451 patients provided eligible mRNA material for subsequent analyses of the MAPK pathway (295 genes). Non-negative matrix factorized (NMF) clustering for normalized mRNA microarray data (Almac Inc, Xcel Array) was performed for 2 to 6 ranks against randomized controls. Linear models with adjustment for multiple testing showed differential gene expression between groups. Single sample gene set enrichment analysis (ssGSEA) was used to compare differentially enriched hallmarks of cancer gene sets. Kaplan Meier metho…