Meyer SN, et al. - In this investigation, researchers identified the frequency of cytokeratin (CK)+/vimentin (VIM)+ tumor cells and described the CK+/VIM+ stroma in colorectal cancer. Using DepArray and fluorescence-activated cell sorting (FACS), three cell populations (CK+, VIM+, CK+/VIM+) were sorted. To visualize co-expressing cells on whole slides, fluorescence microscopy was used. Investigators found that a low proportion of CK+/VIM+ tumor cells (1.5%–22%). Findings suggested CK+ stroma was associated with aggressive tumor features, like distant metastasis, lymphatic invasion and tumor budding. Although in low numbers, CK+/VIM+ tumor cells may represent a subgroup of tumor buds in partial epithelial-mesenchymal transition. CK+/VIM+ stroma can be mesothelial and shows the characteristics of mesenchymal cells and fibroblasts associated with cancer. These outcomes suggest that there is a mesothelial-mesenchymal transition (MMT) of double-positive fibroblast. This atypical stroma can be a potential therapeutic target.