To obtain a comparative transcriptomic profile of both the tumour (i.e., epithelial neoplastic cells) and stromal tissues (i.e., “normal” fibroblasts, endothelial and muscle cells, native and adaptive immune cells) belonging to the same lesion, we performed manual microdissection (Figure S1 and Materials and Methods for details) of paraffin-embedded surgical samples of colorectal cancer patients, with all harbouring KRAS mutations and none carrying BRAF mutations (whose clinicopathological characteristics are shown in Table 1). This evidence concerns the gene KRAS and colorectal cancer.