We read with interest the manuscript from Martínez-Cardús et al,1 which defines methylation heterogeneity, both interpatient and intratumoral, using multiregional sampling in colorectal cancer (CRC). The authors show that samples will cluster according to patient of origin rather than site of sampling. This observation, where only small variations in molecular profiles are found at different tumoral regions, is in agreement with our recent transcriptional-based CRC profiling using multiregional sampling of central tumor and invasive front (IF).