Abstract: Particular aspects provide methods and compositions (e.g., gene marker panels) having substantial utility for at least one of diagnosis, identification and classification of colorectal cancer (CRC) (e.g., tumors) relating to distinctive DNA methylation-based subgroups of CRC including CpG island methylator phenotype (CIMP) groups (e.g., CIMP-H and CIMP-L) and non-CIMP groups. Exemplary marker panels include: B3GAT2, FOXL2, KCNK13, RAB31 and SLIT1 (CIMP marker panel); and FAM78A, FSTL1, KCNC1, MYOCD, and SLC6A4 (CIMP-H marker panel). Further aspects relate to genetic mutations, and other epigenetic markers relating to said CRC subgroups that can be used in combination with the gene marker panels for at least one of diagnosis, identification and classification of colorectal cancer (CRC) (e.g., tumors) relating to distinctive CIMP and non-CIMP groups.