Expression of MAGL is often increased in cancer and promotes cancer pathogenesis, and the high level of 1-MAG observed in our luminal B tumors suggests a selective hydrolysis in the 2-position of the glycerol backbone with concomitant release of specific acyl chains (e.g., arachidonic acid), able to regulate a complex fatty acid network such as prostaglandine, lysophospholipid, and ether lipids, known to be involved in inflammation and tumor progression. This evidence concerns the gene MGLL and cancer.