In CRC, Roulis M et al. described rare pericryptal Ptgs2-expressing fibroblasts exerting paracrine control over tumor-initiating stem cells via the druggable PGE2-Ptger4-Yap signaling axis and considered that the initiation of CRC correlates with the mesenchymal niche (Roulis et al., 2020). This evidence concerns the gene PTGER4 and colorectal carcinoma.