A panel of DNA methylation markers for the classification of consensus molecular subtypes 2 and 3 in patients with colorectal cancer

ABSTRACT: INTRODUCTION. Consensus molecular subtypes (CMSs) can guide precision treatment of colorectal cancer (CRC). Currently available dedicated assays can identify CMS1 and CMS4 cases very well while a dedicated test to distinguish CMS2 and 3 is lacking. This study aimed to identify a panel of methylation markers to distinguish between CMS2 and 3 in patients with CRC. METHODS. Fresh-frozen tumor tissue of 239 patients with stage I-III CRC who underwent surgery between 2007 and 2014 was included. CMS classification was performed on RNA-seq data using the single-sample prediction parameter from the “CMSclassifier” package. Methylation profiles were gathered/obtained using the Infinium HumanMethylation450 BeadChip for 146 samples (124 CMS2 and 22 CMS3) . We performed adaptive group-regularised logistic ridge regression with post-hoc group-weighted elastic net marker selection to build prediction models for classification of CMS2 and CMS3 based on 15, 10 or 5 methylation markers. Data from the Cancer Genome Atlas project was used for independent validation of our obtained models. RESULTS. Overall methylation profiles differed between CMS2 and CMS3 tumors. Group-regularisation of the methylation probes was done based on their location either relative to a CpG island or relative to a gene present in the CMS classifier. This resulted in two different prediction models and subsequently different marker panels. For both panels, even when using only 5 markers, the sensitivity, specificity, and accuracy were >90%. Independent validation of the fixed models in TCGA data showed comparable performances. CONCLUSION. Our highly sensitive and specific methylation marker panel can be used to distinguish CMS2 and 3. This enables future development of a qPCR DNA methylation assay in patients with CRC to provide a specific and non-invasive classification tool.

ORGANISM(S): Homo sapiens

PROVIDER: GSE164811 | GEO | 2021/12/08

REPOSITORIES: GEO